@misc{LauxBierHoelzel2018, author = {Laux, Eva-Maria and Bier, Frank Fabian and H{\"o}lzel, Ralph}, title = {Electrode-based AC electrokinetics of proteins}, series = {Bioelectrochemistry : official journal of the Bioelectrochemical Society ; an international journal devoted to electrochemical aspects of biology and biological aspects of electrochemistry}, volume = {120}, journal = {Bioelectrochemistry : official journal of the Bioelectrochemical Society ; an international journal devoted to electrochemical aspects of biology and biological aspects of electrochemistry}, publisher = {Elsevier B.V.}, address = {Amsterdam}, issn = {1567-5394}, doi = {10.1016/j.bioelechem.2017.11.010}, pages = {76 -- 82}, year = {2018}, abstract = {Employing electric phenomena for the spatial manipulation of bioparticles from whole cells down to dissolved molecules has become a useful tool in biotechnology and analytics. AC electrokinetic effects like dielectrophoresis and AC electroosmosis are increasingly used to concentrate, separate and immobilize DNA and proteins. With the advance of photolithographical micro- and nanofabrication methods, novel or improved bioanalytical applications benefit from concentrating analytes, signal enhancement and locally controlled immobilization by AC electrokinetic effects. In this review of AC electrokinetics of proteins, the respective studies are classified according to their different electrode geometries: individual electrode pairs, interdigitated electrodes, quadrupole electrodes, and 3D configurations of electrode arrays. Known advantages and disadvantages of each layout are discussed.}, language = {en} } @article{KerstingRauschBieretal.2018, author = {Kersting, Sebastian and Rausch, Valentina and Bier, Frank Fabian and von Nickisch-Rosenegk, Markus}, title = {A recombinase polymerase amplification assay for the diagnosis of atypical pneumonia}, series = {Analytical biochemistry : methods in the biological sciences}, volume = {550}, journal = {Analytical biochemistry : methods in the biological sciences}, publisher = {Elsevier}, address = {San Diego}, issn = {0003-2697}, doi = {10.1016/j.ab.2018.04.014}, pages = {54 -- 60}, year = {2018}, abstract = {Pneumonia is one of the most common and potentially lethal infectious conditions worldwide. Streptococcus pneumoniae is the pathogen most frequently associated with bacterial community-acquired pneumonia, while Legionella pneumophila is the major cause for local outbreaks of legionellosis. Both pathogens can be difficult to diagnose since signs and symptoms are nonspecific and do not differ from other causes of pneumonia. Therefore, a rapid diagnosis within a clinically relevant time is essential for a fast onset of the proper treatment. Although methods based on polymerase chain reaction significantly improved the identification of pathogens, they are difficult to conduct and need specialized equipment. We describe a rapid and sensitive test using isothermal recombinase polymerase amplification and detection on a disposable test strip. This method does not require any special instrumentation and can be performed in less than 20 min. The analytical sensitivity in the multiplex assay amplifying specific regions of S. pneumoniae and L. pneumophila simultaneously was 10 CFUs of genomic DNA per reaction. In cross detection studies with closely related strains and other bacterial agents the specificity of the RPA was confirmed. The presented method is applicable for near patient and field testing with a rather simple routine and the possibility for a read out with the naked eye.}, language = {en} } @misc{BreitensteinNielsenHoelzeletal.2011, author = {Breitenstein, Michael and Nielsen, Peter E. and H{\"o}lzel, Ralph and Bier, Frank Fabian}, title = {DNA-nanostructure-assembly by sequential spotting}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1027}, issn = {1866-8372}, doi = {10.25932/publishup-43110}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-431108}, pages = {12}, year = {2011}, abstract = {Background: The ability to create nanostructures with biomolecules is one of the key elements in nanobiotechnology. One of the problems is the expensive and mostly custom made equipment which is needed for their development. We intended to reduce material costs and aimed at miniaturization of the necessary tools that are essential for nanofabrication. Thus we combined the capabilities of molecular ink lithography with DNA-self-assembling capabilities to arrange DNA in an independent array which allows addressing molecules in nanoscale dimensions. Results: For the construction of DNA based nanostructures a method is presented that allows an arrangement of DNA strands in such a way that they can form a grid that only depends on the spotted pattern of the anchor molecules. An atomic force microscope (AFM) has been used for molecular ink lithography to generate small spots. The sequential spotting process allows the immobilization of several different functional biomolecules with a single AFM-tip. This grid which delivers specific addresses for the prepared DNA-strand serves as a two-dimensional anchor to arrange the sequence according to the pattern. Once the DNA-nanoarray has been formed, it can be functionalized by PNA (peptide nucleic acid) to incorporate advanced structures. Conclusions: The production of DNA-nanoarrays is a promising task for nanobiotechnology. The described method allows convenient and low cost preparation of nanoarrays. PNA can be used for complex functionalization purposes as well as a structural element.}, language = {en} } @article{KagelBierFrohmeetal.2019, author = {Kagel, Heike and Bier, Frank Fabian and Frohme, Marcus and Gl{\"o}kler, J{\"o}rn F.}, title = {A Novel Optical Method To Reversibly Control Enzymatic Activity Based On Photoacids}, series = {Scientific reports}, volume = {9}, journal = {Scientific reports}, publisher = {Nature Publishing Group}, address = {London}, issn = {2045-2322}, doi = {10.1038/s41598-019-50867-w}, pages = {6}, year = {2019}, abstract = {Most biochemical reactions depend on the pH value of the aqueous environment and some are strongly favoured to occur in an acidic environment. A non-invasive control of pH to tightly regulate such reactions with defined start and end points is a highly desirable feature in certain applications, but has proven difficult to achieve so far. We report a novel optical approach to reversibly control a typical biochemical reaction by changing the pH and using acid phosphatase as a model enzyme. The reversible photoacid G-acid functions as a proton donor, changing the pH rapidly and reversibly by using high power UV LEDs as an illumination source in our experimental setup. The reaction can be tightly controlled by simply switching the light on and off and should be applicable to a wide range of other enzymatic reactions, thus enabling miniaturization and parallelization through non-invasive optical means.}, language = {en} } @misc{StankeWengerBieretal.2017, author = {Stanke, S. and Wenger, C. and Bier, Frank Fabian and H{\"o}lzel, Ralph}, title = {Dielectrophoretic functionalization of nanoelectrode arrays for the detection of influenza viruses}, series = {European biophysics journal : with biophysics letters ; an international journal of biophysics}, volume = {46}, journal = {European biophysics journal : with biophysics letters ; an international journal of biophysics}, publisher = {Springer}, address = {New York}, issn = {0175-7571}, pages = {S337 -- S337}, year = {2017}, language = {en} } @misc{LauxGibbonsErmilovaetal.2017, author = {Laux, Eva-Maria and Gibbons, J. and Ermilova, Elena and Bier, Frank Fabian and H{\"o}lzel, Ralph}, title = {Broadband dielectric spectroscopy of bovine serum albumin in the GHz range}, series = {European biophysics journal : with biophysics letters ; an international journal of biophysics}, volume = {46}, journal = {European biophysics journal : with biophysics letters ; an international journal of biophysics}, publisher = {Springer}, address = {New York}, issn = {0175-7571}, pages = {S347 -- S347}, year = {2017}, language = {en} } @misc{LauxKniggeWengeretal.2017, author = {Laux, Eva-Maria and Knigge, Xenia and Wenger, C. and Bier, Frank Fabian and H{\"o}lzel, Ralph}, title = {AC electrokinetic manipulation of nanoparticles and molecules}, series = {European biophysics journal : with biophysics letters ; an international journal of biophysics}, volume = {46}, journal = {European biophysics journal : with biophysics letters ; an international journal of biophysics}, publisher = {Springer}, address = {New York}, issn = {0175-7571}, pages = {S189 -- S189}, year = {2017}, language = {en} } @misc{KniggeWengerBieretal.2017, author = {Knigge, Xenia and Wenger, C. and Bier, Frank Fabian and H{\"o}lzel, Ralph}, title = {AC electrokinetic immobilisation of nanoobjects as individual singles in regular arrays}, series = {European biophysics journal : with biophysics letters ; an international journal of biophysics}, volume = {46}, journal = {European biophysics journal : with biophysics letters ; an international journal of biophysics}, publisher = {Springer}, address = {New York}, issn = {0175-7571}, pages = {S187 -- S187}, year = {2017}, language = {en} } @article{ConnorDanckertHoppeetal.2017, author = {Connor, Daniel Oliver and Danckert, Lena and Hoppe, Sebastian and Bier, Frank Fabian and von Nickisch-Rosenegk, Markus}, title = {Epitope determination of immunogenic proteins of Neisseria gonorrhoeae}, series = {PLoS one}, volume = {12}, journal = {PLoS one}, publisher = {PLoS}, address = {San Fransisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0180962}, pages = {18}, year = {2017}, abstract = {Neisseria gonorrhoeae is the causative organism of gonorrhoea, a sexually transmitted disease that globally accounts for an estimated 80 to 100 million new infections per year. Increasing resistances to all common antibiotics used for N. gonorrhoeae treatment pose the risk of an untreatable disease. Further knowledge of ways of infection and host immune response are needed to understand the pathogen-host interaction and to discover new treatment alternatives against this disease. Therefore, detailed information about immunogenic proteins and their properties like epitope sites could advance further research in this area. In this work, we investigated immunogenic proteins of N. gonorrhoeae for linear epitopes by microarrays. Dominant linear epitopes were identified for eleven of the nineteen investigated proteins with three polyclonal rabbit antibodies from different immunisations. Identified linear epitopes were further examined for non-specific binding with antibodies to Escherichia coli and the closely related pathogen Neisseria meningitidis. On top of that, amino acids crucial for the antibody epitope binding were detected by microarray based alanine scans.}, language = {en} } @article{BaderKlierHettrichetal.2016, author = {Bader, Denise and Klier, Dennis Tobias and Hettrich, C. and Bier, Frank Fabian and Wessig, Pablo}, title = {Detecting carbohydrate-lectin interactions using a fluorescent probe based on DBD dyes}, series = {Analytical methods : advancing methods and applications}, volume = {8}, journal = {Analytical methods : advancing methods and applications}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1759-9660}, doi = {10.1039/c5ay02991k}, pages = {1235 -- 1238}, year = {2016}, abstract = {Herein we present an efficient synthesis of a biomimetic probe with modular construction that can be specifically bound by the mannose binding FimH protein - a surface adhesion protein of E. coli bacteria. The synthesis combines the new and interesting DBD dye with the carbohydrate ligand mannose via a Click reaction. We demonstrate the binding to E. coli bacteria over a large concentration range and also present some special characteristics of those molecules that are of particular interest for the application as a biosensor. In particular, the mix-and-measure ability and the very good photo-stability should be highlighted here.}, language = {en} } @article{ConnorZantowHustetal.2016, author = {Connor, Daniel Oliver and Zantow, Jonas and Hust, Michael and Bier, Frank Fabian and von Nickisch-Rosenegk, Markus}, title = {Identification of Novel Immunogenic Proteins of Neisseria gonorrhoeae by Phage Display}, series = {PLoS one}, volume = {11}, journal = {PLoS one}, publisher = {PLoS}, address = {San Fransisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0148986}, pages = {24}, year = {2016}, abstract = {Neisseria gonorrhoeae is one of the most prevalent sexually transmitted diseases worldwide with more than 100 million new infections per year. A lack of intense research over the last decades and increasing resistances to the recommended antibiotics call for a better understanding of gonococcal infection, fast diagnostics and therapeutic measures against N. gonorrhoeae. Therefore, the aim of this work was to identify novel immunogenic proteins as a first step to advance those unresolved problems. For the identification of immunogenic proteins, pHORF oligopeptide phage display libraries of the entire N. gonorrhoeae genome were constructed. Several immunogenic oligopeptides were identified using polyclonal rabbit antibodies against N. gonorrhoeae. Corresponding full-length proteins of the identified oligopeptides were expressed and their immunogenic character was verified by ELISA. The immunogenic character of six proteins was identified for the first time. Additional 13 proteins were verified as immunogenic proteins in N. gonorrhoeae.}, language = {en} } @article{MemczakLausterKaretal.2016, author = {Memczak, Henry and Lauster, Daniel and Kar, Parimal and Di Lella, Santiago and Volkmer, Rudolf and Knecht, Volker and Herrmann, Andreas and Ehrentreich-Foerster, Eva and Bier, Frank Fabian and Stoecklein, Walter F. M.}, title = {Anti-Hemagglutinin Antibody Derived Lead Peptides for Inhibitors of Influenza Virus Binding}, series = {PLoS one}, volume = {11}, journal = {PLoS one}, publisher = {PLoS}, address = {San Fransisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0159074}, pages = {82 -- 90}, year = {2016}, abstract = {Antibodies against spike proteins of influenza are used as a tool for characterization of viruses and therapeutic approaches. However, development, production and quality control of antibodies is expensive and time consuming. To circumvent these difficulties, three peptides were derived from complementarity determining regions of an antibody heavy chain against influenza A spike glycoprotein. Their binding properties were studied experimentally, and by molecular dynamics simulations. Two peptide candidates showed binding to influenza A/Aichi/2/68 H3N2. One of them, termed PeB, with the highest affinity prevented binding to and infection of target cells in the micromolar region without any cytotoxic effect. PeB matches best the conserved receptor binding site of hemagglutinin. PeB bound also to other medical relevant influenza strains, such as human-pathogenic A/California/7/2009 H1N1, and avian-pathogenic A/MuteSwan/Rostock/R901/2006 H7N1. Strategies to improve the affinity and to adapt specificity are discussed and exemplified by a double amino acid substituted peptide, obtained by substitutional analysis. The peptides and their derivatives are of great potential for drug development as well as biosensing.}, language = {en} } @misc{WessigBaderKlieretal.2016, author = {Wessig, Pablo and Bader, Denise and Klier, Dennis Tobias and Hettrich, Cornelia and Bier, Frank Fabian}, title = {Detecting carbohydrate-lectin interactions using a fluorescent probe based on DBD dyes}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-394382}, pages = {1235 -- 1238}, year = {2016}, abstract = {Herein we present an efficient synthesis of a biomimetic probe with modular construction that can be specifically bound by the mannose binding FimH protein - a surface adhesion protein of E. coli bacteria. The synthesis combines the new and interesting DBD dye with the carbohydrate ligand mannose via a Click reaction. We demonstrate the binding to E. coli bacteria over a large concentration range and also present some special characteristics of those molecules that are of particular interest for the application as a biosensor. In particular, the mix-and-measure ability and the very good photo-stability should be highlighted here.}, language = {en} } @article{HuettlHettrichRiedeletal.2015, author = {H{\"u}ttl, Christine and Hettrich, Cornelia and Riedel, Melanie and Henklein, Petra and Rawel, Harshadrai Manilal and Bier, Frank Fabian}, title = {Development of Peptidyl Lysine Dendrons: 1,3-Dipolar Cycloaddition for Peptide Coupling and Antibody Recognition}, series = {Chemical biology \& drug design}, volume = {85}, journal = {Chemical biology \& drug design}, number = {5}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {1747-0277}, doi = {10.1111/cbdd.12444}, pages = {565 -- 573}, year = {2015}, abstract = {A straightforward synthesis strategy to multimerize a peptide mimotopes for antibody B13-DE1 recognition is described based on lysine dendrons as multivalent scaffolds. Lysine dendrons that possess N-terminal alkyne residues at the periphery were quantitative functionalized with azido peptides using click chemistry. The solid-phase peptide synthesis (SPPS) allows preparing the peptide dendron in high purity and establishing the possibility of automation. The presented peptide dendron is a promising candidate as multivalent ligand and was used for antibody B13-DE1 recognition. The binding affinity increases with higher dendron generation without loss of specificity. The analysis of biospecific interaction between the synthesized peptide dendron and the antibody was done via surface plasmon resonance (SPR) technique. The presented results show a promising tool for investigations of antigen-antibody reactions.}, language = {en} } @article{TanneJeoungPengetal.2015, author = {Tanne, Johannes and Jeoung, Jae-Hun and Peng, Lei and Yarman, Aysu and Dietzel, Birgit and Schulz, Burkhard and Schad, Daniel and Dobbek, Holger and Wollenberger, Ursula and Bier, Frank Fabian and Scheller, Frieder W.}, title = {Direct Electron Transfer and Bioelectrocatalysis by a Hexameric, Heme Protein at Nanostructured Electrodes}, series = {Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis}, volume = {27}, journal = {Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis}, number = {10}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1040-0397}, doi = {10.1002/elan.201500231}, pages = {2262 -- 2267}, year = {2015}, abstract = {A nanohybrid consisting of poly(3-aminobenzenesulfonic acid-co-aniline) and multiwalled carbon nanotubes [MWCNT-P(ABS-A)]) on a gold electrode was used to immobilize the hexameric tyrosine-coordinated heme protein (HTHP). The enzyme showed direct electron transfer between the heme group of the protein and the nanostructured surface. Desorption of the noncovalently bound heme from the protein could be excluded by control measurements with adsorbed hemin on aminohexanthiol-modified electrodes. The nanostructuring and the optimised charge characteristics resulted in a higher protein coverage as compared with MUA/MU modified electrodes. The adsorbed enzyme shows catalytic activity for the cathodic H2O2 reduction and oxidation of NADH.}, language = {en} } @article{SchmitzHertzbergLieseTerjungetal.2014, author = {Schmitz-Hertzberg, Sebastian-Tim and Liese, Rick and Terjung, Carsten and Bier, Frank Fabian}, title = {Towards a smart encapsulation system for small-sized electronic devices: a new approach}, series = {International journal of polymer science}, journal = {International journal of polymer science}, publisher = {Hindawi Publishing Corp.}, address = {New York}, issn = {1687-9422}, doi = {10.1155/2014/713603}, pages = {12}, year = {2014}, abstract = {Miniaturized analytical chip devices like biosensors nowadays provide assistance in highly diverse fields of application such as point-of-care diagnostics and industrial bioprocess engineering. However, upon contact with fluids, the sensor requires a protective shell for its electrical components that simultaneously offers controlled access for the target analytes to the measuring units. We therefore developed a capsule that comprises a permeable and a sealed compartment consisting of variable polymers such as biocompatible and biodegradable polylactic acid (PLA) for medical applications or more economical polyvinyl chloride (PVC) and polystyrene (PS) polymers for bioengineering applications. Production of the sealed capsule compartments was performed by heat pressing of polymer pellets placed in individually designable molds. Controlled permeability of the opposite compartments was achieved by inclusion of NaCl inside the polymer matrix during heat pressing, followed by its subsequent release in aqueous solution. Correlating diffusion rates through the so made permeable capsule compartments were quantified for preselected model analytes: glucose, peroxidase, and polystyrene beads of three different diameters (1.4 mu m, 4.2 mu m, and 20.0 mu m). In summary, the presented capsule system turned out to provide sufficient shelter for small-sized electronic devices and gives insight into its potential permeability for defined substances of analytical interest.}, language = {en} } @article{SchellerYarmanBachmannetal.2014, author = {Scheller, Frieder W. and Yarman, Aysu and Bachmann, Till and Hirsch, Thomas and Kubick, Stefan and Renneberg, Reinhard and Schumacher, Soeren and Wollenberger, Ursula and Teller, Carsten and Bier, Frank Fabian}, title = {Future of biosensors: a personal view}, series = {Advances in biochemical engineering, biotechnology}, volume = {140}, journal = {Advances in biochemical engineering, biotechnology}, editor = {Gu, MB and Kim, HS}, publisher = {Springer}, address = {Berlin}, isbn = {978-3-642-54143-8; 978-3-642-54142-1}, issn = {0724-6145}, doi = {10.1007/10_2013_251}, pages = {1 -- 28}, year = {2014}, abstract = {Biosensors representing the technological counterpart of living senses have found routine application in amperometric enzyme electrodes for decentralized blood glucose measurement, interaction analysis by surface plasmon resonance in drug development, and to some extent DNA chips for expression analysis and enzyme polymorphisms. These technologies have already reached a highly advanced level and need minor improvement at most. The dream of the "100-dollar' personal genome may come true in the next few years provided that the technological hurdles of nanopore technology or of polymerase-based single molecule sequencing can be overcome. Tailor-made recognition elements for biosensors including membrane-bound enzymes and receptors will be prepared by cell-free protein synthesis. As alternatives for biological recognition elements, molecularly imprinted polymers (MIPs) have been created. They have the potential to substitute antibodies in biosensors and biochips for the measurement of low-molecular-weight substances, proteins, viruses, and living cells. They are more stable than proteins and can be produced in large amounts by chemical synthesis. Integration of nanomaterials, especially of graphene, could lead to new miniaturized biosensors with high sensitivity and ultrafast response. In the future individual therapy will include genetic profiling of isoenzymes and polymorphic forms of drug-metabolizing enzymes especially of the cytochrome P450 family. For defining the pharmacokinetics including the clearance of a given genotype enzyme electrodes will be a useful tool. For decentralized online patient control or the integration into everyday "consumables' such as drinking water, foods, hygienic articles, clothing, or for control of air conditioners in buildings and cars and swimming pools, a new generation of "autonomous' biosensors will emerge.}, language = {en} } @article{KerstingRauschBieretal.2014, author = {Kersting, Sebastian and Rausch, Valentina and Bier, Frank Fabian and von Nickisch-Rosenegk, Markus}, title = {Rapid detection of Plasmodium falciparum with isothermal recombinase polymerase amplification and lateral flow analysis}, series = {Malaria journal}, volume = {13}, journal = {Malaria journal}, publisher = {BioMed Central}, address = {London}, issn = {1475-2875}, doi = {10.1186/1475-2875-13-99}, pages = {9}, year = {2014}, abstract = {Background: Nucleic acid amplification is the most sensitive and specific method to detect Plasmodium falciparum. However the polymerase chain reaction remains laboratory-based and has to be conducted by trained personnel. Furthermore, the power dependency for the thermocycling process and the costly equipment necessary for the read-out are difficult to cover in resource-limited settings. This study aims to develop and evaluate a combination of isothermal nucleic acid amplification and simple lateral flow dipstick detection of the malaria parasite for point-of-care testing. Methods: A specific fragment of the 18S rRNA gene of P. falciparum was amplified in 10 min at a constant 38 C using the isothermal recombinase polymerase amplification (RPA) method. With a unique probe system added to the reaction solution, the amplification product can be visualized on a simple lateral flow strip without further labelling. The combination of these methods was tested for sensitivity and specificity with various Plasmodium and other protozoa/bacterial strains, as well as with human DNA. Additional investigations were conducted to analyse the temperature optimum, reaction speed and robustness of this assay. Results: The lateral flow RPA (LF-RPA) assay exhibited a high sensitivity and specificity. Experiments confirmed a detection limit as low as 100 fg of genomic P. falciparum DNA, corresponding to a sensitivity of approximately four parasites per reaction. All investigated P. falciparum strains (n = 77) were positively tested while all of the total 11 non-Plasmodium samples, showed a negative test result. The enzymatic reaction can be conducted under a broad range of conditions from 30-45 degrees C with high inhibitory concentration of known PCR inhibitors. A time to result of 15 min from start of the reaction to read-out was determined. Conclusions: Combining the isothermal RPA and the lateral flow detection is an approach to improve molecular diagnostic for P. falciparum in resource-limited settings. The system requires none or only little instrumentation for the nucleic acid amplification reaction and the read-out is possible with the naked eye. Showing the same sensitivity and specificity as comparable diagnostic methods but simultaneously increasing reaction speed and dramatically reducing assay requirements, the method has potential to become a true point-of-care test for the malaria parasite.}, language = {en} } @article{DechtriratGajovicEichelmannWojciketal.2014, author = {Dechtrirat, Decha and Gajovic-Eichelmann, Nenad and Wojcik, Felix and Hartmann, Laura and Bier, Frank Fabian and Scheller, Frieder W.}, title = {Electrochemical displacement sensor based on ferrocene boronic acid tracer and immobilized glycan for saccharide binding proteins and E. coli}, series = {Biosensors and bioelectronics : the principal international journal devoted to research, design development and application of biosensors and bioelectronics}, volume = {58}, journal = {Biosensors and bioelectronics : the principal international journal devoted to research, design development and application of biosensors and bioelectronics}, publisher = {Elsevier}, address = {Oxford}, issn = {0956-5663}, doi = {10.1016/j.bios.2014.02.028}, pages = {1 -- 8}, year = {2014}, abstract = {Pathogens such as viruses and bacteria use their envelope proteins and their adhesin lectins to recognize the glycan residues presented on the cell surface of the target tissues. This principle of recognition is used in a new electrochemical displacement sensor for the protein concanavalin A (ConA). A gold electrode was first modified with a self-assembled monolayer of a thiolated mannose/OEG conjugate and a ferrocene boroxol derivative was pre-assembled as reporter molecule onto the mannose surface. The novel tracer molecule based on a 2-hydroxymethyl phenyl boronic acid derivative binds even at neutral pH to the saccharides which could expand the application towards biological samples (i.e., urine and feces). Upon the binding of ConA, the tracer was displaced and washed away from the sensor surface leading to a decrease in the electrochemical signal. Using square wave voltammetry (SWV), the concentration of ConA in the sample solution could be determined in the dynamic concentration range established from 38 nmol L-1 to 5.76 mu mol L-1 with a reproducible detection limit of 1 mu g mL(-1) (38 nmol L-1) based on the signal-to-noise ratio (S/N=3) with fast response of 15 min. The new reporter molecule showed a reduced non-specific displacement by BSA and ribonuclease A. The sensor was also successfully transferred to the first proof of principle for the detection of Escherichia coli exhibiting a detection limit of approximately 6 x 102 cells/mL Specificity of the displacement by target protein ConA and E. coli was demonstrated since the control proteins (i.e., BSA and RNaseA) and the control E. coli strain, which lack of type 1 fimbriae, were ineffective. (C) 2014 Elsevier B.V. All rights reserved.}, language = {en} } @article{KerstingRauschBieretal.2014, author = {Kersting, Sebastian and Rausch, Valentina and Bier, Frank Fabian and von Nickisch-Rosenegk, Markus}, title = {Multiplex isothermal solid-phase recombinase polymerase amplification for the specific and fast DNA-based detection of three bacterial pathogens}, series = {Microchimica acta : analytical sciences based on micro- and nanomaterials}, volume = {181}, journal = {Microchimica acta : analytical sciences based on micro- and nanomaterials}, number = {13-14}, publisher = {Springer}, address = {Wien}, issn = {0026-3672}, doi = {10.1007/s00604-014-1198-5}, pages = {1715 -- 1723}, year = {2014}, abstract = {We report on the development of an on-chip RPA (recombinase polymerase amplification) with simultaneous multiplex isothermal amplification and detection on a solid surface. The isothermal RPA was applied to amplify specific target sequences from the pathogens Neisseria gonorrhoeae, Salmonella enterica and methicillin-resistant Staphylococcus aureus (MRSA) using genomic DNA. Additionally, a positive plasmid control was established as an internal control. The four targets were amplified simultaneously in a quadruplex reaction. The amplicon is labeled during on-chip RPA by reverse oligonucleotide primers coupled to a fluorophore. Both amplification and spatially resolved signal generation take place on immobilized forward primers bount to expoxy-silanized glass surfaces in a pump-driven hybridization chamber. The combination of microarray technology and sensitive isothermal nucleic acid amplification at 38 degrees C allows for a multiparameter analysis on a rather small area. The on-chip RPA was characterized in terms of reaction time, sensitivity and inhibitory conditions. A successful enzymatic reaction is completed in < 20 min and results in detection limits of 10 colony-forming units for methicillin-resistant Staphylococcus aureus and Salmonella enterica and 100 colony-forming units for Neisseria gonorrhoeae. The results show this method to be useful with respect to point-of-care testing and to enable simplified and miniaturized nucleic acid-based diagnostics.}, language = {en} } @article{HoppeBiervonNickischRosenegk2014, author = {Hoppe, Sebastian and Bier, Frank Fabian and von Nickisch-Rosenegk, Markus}, title = {Identification of antigenic proteins of the nosocomial pathogen klebsiella pneumoniae}, series = {PLoS one}, volume = {9}, journal = {PLoS one}, number = {10}, publisher = {PLoS}, address = {San Fransisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0110703}, pages = {16}, year = {2014}, abstract = {The continuous expansion of nosocomial infections around the globe has become a precarious situation. Key challenges include mounting dissemination of multiple resistances to antibiotics, the easy transmission and the growing mortality rates of hospital-acquired bacterial diseases. Thus, new ways to rapidly detect these infections are vital. Consequently, researchers around the globe pursue innovative approaches for point-of-care devices. In many cases the specific interaction of an antigen and a corresponding antibody is pivotal. However, the knowledge about suitable antigens is lacking. The aim of this study was to identify novel antigens as specific diagnostic markers. Additionally, these proteins might be aptly used for the generation of vaccines to improve current treatment options. Hence, a cDNA-based expression library was constructed and screened via microarrays to detect novel antigens of Klebsiella pneumoniae, a prominent agent of nosocomial infections well-known for its extensive antibiotics resistance, especially by extended-spectrum beta-lactamases (ESBL). After screening 1536 clones, 14 previously unknown immunogenic proteins were identified. Subsequently, each protein was expressed in full-length and its immunodominant character examined by ELISA and microarray analyses. Consequently, six proteins were selected for epitope mapping and three thereof possessed linear epitopes. After specificity analysis, homology survey and 3d structural modelling, one epitope sequence GAVVALSTTFA of KPN_00363, an ion channel protein, was identified harboring specificity for K. pneumoniae. The remaining epitopes showed ambiguous results regarding the specificity for K. pneumoniae. The approach adopted herein has been successfully utilized to discover novel antigens of Campylobacter jejuni and Salmonella enterica antigens before. Now, we have transferred this knowledge to the key nosocomial agent, K. pneumoniae. By identifying several novel antigens and their linear epitope sites, we have paved the way for crucial future research and applications including the design of point-of-care devices, vaccine development and serological screenings for a highly relevant nosocomial pathogen.}, language = {en} } @article{HovestaedtMemczakPleineretal.2014, author = {Hovestaedt, Marc and Memczak, Henry and Pleiner, Dennis and Zhang, Xin and Rappich, Joerg and Bier, Frank Fabian and St{\"o}cklein, Walter F. M.}, title = {Characterization of a new maleimido functionalization of gold for surface plasmon resonance spectroscopy}, series = {Journal of molecular recognition : an international journal devoted to research on specific molecular recognition in chemistry, biology, biotechnology and medicine}, volume = {27}, journal = {Journal of molecular recognition : an international journal devoted to research on specific molecular recognition in chemistry, biology, biotechnology and medicine}, number = {12}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0952-3499}, doi = {10.1002/jmr.2396}, pages = {707 -- 713}, year = {2014}, abstract = {Para-maleimidophenyl (p-MP) modified gold surfaces have been prepared by one-step electrochemical deposition and used in surface plasmon resonance (SPR) studies. Therefore, a FITC mimotope peptide (MP1, 12 aa), a human mucin 1 epitope peptide (MUC, 9 aa) and a protein with their specific antibodies were used as model systems. The peptides were modified with an N-terminal cysteine for covalent and directed coupling to the maleimido functionalized surface by means of Michael addition. The coupling yield of the peptide, the binding characteristics of antibody and the unspecific adsorption of the analytes were investigated. The results expand the spectrum of biosensors usable with p-MP by widely used SPR and support its potential to be versatile for several electrochemical and optical biosensors. This allows the combination of an electrochemical and optical read-out for a broad variety of biomolecular interactions on the same chip. Copyright (c) 2014 John Wiley \& Sons, Ltd.}, language = {en} } @article{StankeBierHoezel2011, author = {Stanke, Sandra and Bier, Frank Fabian and Hoezel, Ralph}, title = {Fluid streaming above interdigitated electrodes in dielectrophoresis experiments}, series = {Electrophoresis : microfluidics, nanoanalysis \& proteomics}, volume = {32}, journal = {Electrophoresis : microfluidics, nanoanalysis \& proteomics}, number = {18}, publisher = {Wiley-Blackwell}, address = {Malden}, issn = {0173-0835}, doi = {10.1002/elps.201100096}, pages = {2448 -- 2455}, year = {2011}, abstract = {For the investigation of alternating current electrokinetic effects, a system is presented that allows for the simultaneous observation of fluid flow above and around microelectrodes in all three directions in space. Beside the usual microscopical view from top, lateral observation through the same objective is made possible by two small mirrors that are placed next to the electrodes. Fluid flow and movement of fluorescent nanoparticles above interdigitated electrodes are monitored by fluorescence microscopy and digital imaging and are further analysed by image processing. Field frequencies are varied from 10 Hz to 1 GHz at up to 10V(rms). Electrical conductivity of the fluid is monitored in situ in the actual measuring chamber.}, language = {en} } @article{BreitensteinNielsenHoelzeletal.2011, author = {Breitenstein, Michael and Nielsen, Peter E. and H{\"o}lzel, Ralph and Bier, Frank Fabian}, title = {DNA-nanostructure-assembly by sequential spotting}, series = {Journal of nanobiotechnology}, volume = {9}, journal = {Journal of nanobiotechnology}, number = {11}, publisher = {BioMed Central}, address = {London}, issn = {1477-3155}, doi = {10.1186/1477-3155-9-54}, pages = {10}, year = {2011}, abstract = {Background: The ability to create nanostructures with biomolecules is one of the key elements in nanobiotechnology. One of the problems is the expensive and mostly custom made equipment which is needed for their development. We intended to reduce material costs and aimed at miniaturization of the necessary tools that are essential for nanofabrication. Thus we combined the capabilities of molecular ink lithography with DNA-self-assembling capabilities to arrange DNA in an independent array which allows addressing molecules in nanoscale dimensions. Results: For the construction of DNA based nanostructures a method is presented that allows an arrangement of DNA strands in such a way that they can form a grid that only depends on the spotted pattern of the anchor molecules. An atomic force microscope (AFM) has been used for molecular ink lithography to generate small spots. The sequential spotting process allows the immobilization of several different functional biomolecules with a single AFM-tip. This grid which delivers specific addresses for the prepared DNA-strand serves as a two-dimensional anchor to arrange the sequence according to the pattern. Once the DNA-nanoarray has been formed, it can be functionalized by PNA (peptide nucleic acid) to incorporate advanced structures. Conclusions: The production of DNA-nanoarrays is a promising task for nanobiotechnology. The described method allows convenient and low cost preparation of nanoarrays. PNA can be used for complex functionalization purposes as well as a structural element.}, language = {en} } @unpublished{BaretBelderBieretal.2012, author = {Baret, Jean-Christophe and Belder, Detlev and Bier, Frank Fabian and Cao, Jialan and Gruschke, Oliver and Hardt, Steffen and Kirschbaum, Michael and Koehler, J. Michael and Schumacher, Soeren and Urban, G. A. and Viefhues, Martina}, title = {Contributors to the 10th Anniversary Germany issue}, series = {LAB on a chip : miniaturisation for chemistry and biology}, volume = {12}, journal = {LAB on a chip : miniaturisation for chemistry and biology}, number = {3}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1473-0197}, doi = {10.1039/c1lc90139g}, pages = {419 -- 421}, year = {2012}, language = {en} } @article{HoppeBiervonNickischRosenegk2012, author = {Hoppe, Sebastian and Bier, Frank Fabian and von Nickisch-Rosenegk, Markus}, title = {Microarray-based method for screening of immunogenic proteins from bacteria}, series = {Journal of nanobiotechnology}, volume = {10}, journal = {Journal of nanobiotechnology}, publisher = {BioMed Central}, address = {London}, issn = {1477-3155}, doi = {10.1186/1477-3155-10-12}, pages = {12}, year = {2012}, abstract = {Background: Detection of immunogenic proteins remains an important task for life sciences as it nourishes the understanding of pathogenicity, illuminates new potential vaccine candidates and broadens the spectrum of biomarkers applicable in diagnostic tools. Traditionally, immunoscreenings of expression libraries via polyclonal sera on nitrocellulose membranes or screenings of whole proteome lysates in 2-D gel electrophoresis are performed. However, these methods feature some rather inconvenient disadvantages. Screening of expression libraries to expose novel antigens from bacteria often lead to an abundance of false positive signals owing to the high cross reactivity of polyclonal antibodies towards the proteins of the expression host. A method is presented that overcomes many disadvantages of the old procedures. Results: Four proteins that have previously been described as immunogenic have successfully been assessed immunogenic abilities with our method. One protein with no known immunogenic behaviour before suggested potential immunogenicity. We incorporated a fusion tag prior to our genes of interest and attached the expressed fusion proteins covalently on microarrays. This enhances the specific binding of the proteins compared to nitrocellulose. Thus, it helps to reduce the number of false positives significantly. It enables us to screen for immunogenic proteins in a shorter time, with more samples and statistical reliability. We validated our method by employing several known genes from Campylobacter jejuni NCTC 11168. Conclusions: The method presented offers a new approach for screening of bacterial expression libraries to illuminate novel proteins with immunogenic features. It could provide a powerful and attractive alternative to existing methods and help to detect and identify vaccine candidates, biomarkers and potential virulence-associated factors with immunogenic behaviour furthering the knowledge of virulence and pathogenicity of studied bacteria.zeige weniger}, language = {en} } @article{LinckReissBieretal.2012, author = {Linck, Lena and Reiss, Edda and Bier, Frank Fabian and Resch-Genger, Ute}, title = {Direct labeling rolling circle amplification as a straightforward signal amplification technique for biodetection formats}, series = {Analytical methods : advancing methods and applications}, volume = {4}, journal = {Analytical methods : advancing methods and applications}, number = {5}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1759-9660}, doi = {10.1039/c2ay05760c}, pages = {1215 -- 1220}, year = {2012}, abstract = {Biodetection formats, such as DNA and antibody microarrays, are valuable tools in the life sciences, but for some applications, the detection limits are insufficient. A straightforward strategy to obtain signal amplification is the rolling circle amplification (RCA), an easy, isothermal, and enzymatic nucleic acid synthesis that has already been employed successfully to increase the signal yield for several single-analyte and multiplexing assays in conjunction with hybridization probes. Here, we systematically investigated the parameters responsible for the RCA driven signal amplification with fluorescent labels, such as the type of fluorophore chosen, labeling strategy, composition of reaction solution, and number of handling steps. In labeling strategies, post-synthetic labeling via a Cy3-hybridization probe was compared to the direct incorporation of fluorescent Cy3-dUTP and DY-555-dUTP into the nascent strand during synthesis. With our direct labeling protocol, the assay's runtime and handling steps could be reduced while the signal yield was increased. These features are very attractive for many detection formats but especially for point-of-care diagnostic kits that need to be simple enough to be performed by scientifically untrained personnel.}, language = {en} } @article{StechMerkSchenketal.2012, author = {Stech, Marlitt and Merk, Helmut and Schenk, J{\"o}rg A. and St{\"o}cklein, Walter F. M. and W{\"u}stenhagen, Doreen Anja and Micheel, Burkhard and Duschl, Claus and Bier, Frank Fabian and Kubick, Stefan}, title = {Production of functional antibody fragments in a vesicle-based eukaryotic cell-free translation system}, series = {Journal of biotechnology}, volume = {164}, journal = {Journal of biotechnology}, number = {2}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0168-1656}, doi = {10.1016/j.jbiotec.2012.08.020}, pages = {220 -- 231}, year = {2012}, abstract = {Cell-free protein synthesis is of increasing interest for the rapid and high-throughput synthesis of many proteins, in particular also antibody fragments. In this study, we present a novel strategy for the production of single chain antibody fragments (scFv) in a eukaryotic in vitro translation system. This strategy comprises the cell-free expression, isolation and label-free interaction analysis of a model antibody fragment synthesized in two differently prepared insect cell lysates. These lysates contain translocationally active microsomal structures derived from the endoplasmic reticulum (ER), allowing for posttranslational modifications of cell-free synthesized proteins. Both types of these insect cell lysates enable the synthesis and translocation of scFv into ER-derived vesicles. However, only the one that has a specifically adapted redox potential yields functional active antibody fragments. We have developed a new methodology for the isolation of functional target proteins based on the translocation of cell-free produced scFv into microsomal structures and subsequent collection of protein-enriched vesicles. Antibody fragments that have been released from these vesicles are shown to be well suited for label-free binding studies. Altogether, these results show the potential of insect cell lysates for the production, purification and selection of antibody fragments in an easy-to-handle and time-saving manner.}, language = {en} } @article{SachseWuestenhagenSamalikovaetal.2013, author = {Sachse, Rita and W{\"u}stenhagen, Doreen Anja and Samalikova, Maria and Gerrits, Michael and Bier, Frank Fabian and Kubick, Stefan}, title = {Synthesis of membrane proteins in eukaryotic cell-free systems}, series = {Engineering in life sciences : Industry, Environment, Plant, Food}, volume = {13}, journal = {Engineering in life sciences : Industry, Environment, Plant, Food}, number = {1}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {1618-0240}, doi = {10.1002/elsc.201100235}, pages = {39 -- 48}, year = {2013}, abstract = {Cell-free protein synthesis (CFPS) is a valuable method for the fast expression of difficult-to-express proteins as well as posttranslationally modified proteins. Since cell-free systems circumvent possible cytotoxic effects caused by protein overexpression in living cells, they significantly enlarge the scale and variety of proteins that can be characterized. We demonstrate the high potential of eukaryotic CFPS to express various types of membrane proteins covering a broad range of structurally and functionally diverse proteins. Our eukaryotic cell-free translation systems are capable to provide high molecular weight membrane proteins, fluorescent-labeled membrane proteins, as well as posttranslationally modified proteins for further downstream analysis.}, language = {en} } @inproceedings{MemczakLausterHerrmannetal.2013, author = {Memczak, Henry and Lauster, Daniel and Herrmann, Andreas and St{\"o}cklein, Walter F. M. and Bier, Frank Fabian}, title = {Novel hemagglutinin-binding peptides for biosensing and inhibition of Influenza Viruses}, series = {Biopolymers}, volume = {100}, booktitle = {Biopolymers}, number = {3}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0006-3525}, pages = {255 -- 255}, year = {2013}, language = {en} } @article{HoppeBiervonNickischRosenegk2013, author = {Hoppe, Sebastian and Bier, Frank Fabian and von Nickisch-Rosenegk, Markus}, title = {Rapid identification of novel immunodominant proteins and characterization of a specific linear epitope of campylobacter jejuni}, series = {PLoS one}, volume = {8}, journal = {PLoS one}, number = {5}, publisher = {PLoS}, address = {San Fransisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0065837}, pages = {15}, year = {2013}, abstract = {Campylobacter jejuni remains one of the major gut pathogens of our time. Its zoonotic nature and wide-spread distribution in industrialized countries calls for a quick and reliable diagnostic tool. Antibody-based detection presents a suitable means to identify pathogenic bacteria. However, the knowledge about immunodominant targets is limited. Thus, an approach is presented, which allows for the rapid screening of numerous cDNA derived expression clones to identify novel antigens. The deeper understanding of immunodominant proteins assists in the design of diagnostic tools and furthers the insight into the bacterium's pathogenicity as well as revealing potential candidates for vaccination. We have successfully screened 1536 clones of an expression library to identify 22 proteins that have not been described as immunodominant before. After subcloning the corresponding 22 genes and expression of full-length proteins, we investigated the immunodominant character by microarrays and ELISA. Subsequently, seven proteins were selected for epitope mapping. For cj0669 and cj0920c linear epitopes were identified. For cj0669, specificity assays revealed a specific linear epitope site. Consequently, an eleven amino acid residue sequence TLIKELKRLGI was analyzed via alanine scan, which revealed the glycine residue to be significant for binding of the antibody. The innovative approach presented herein of generating cDNAs of prokaryotes in combination with a microarray platform rendering time-consuming purification steps obsolete has helped to illuminate novel immunodominant proteins of C. jejuni. The findings of a specific linear epitope pave the way for a plethora of future research and the potential use in diagnostic applications such as serological screenings. Moreover, the current approach is easily adaptable to other highly relevant bacteria making it a formidable tool for the future discovery of antigens and potential biomarkers. Consequently, it is desirable to simplify the identification of structural epitopes, as this would extend the spectrum of novel epitopes to be detected.}, language = {en} } @article{HuettlHettrichMilleretal.2013, author = {H{\"u}ttl, Christine and Hettrich, Cornelia and Miller, Reinhard and Paulke, Bernd-Reiner and Henklein, Petra and Rawel, Harshadrai Manilal and Bier, Frank Fabian}, title = {Self-assembled peptide amphiphiles function as multivalent binder with increased hemagglutinin affinity}, series = {BMC biotechnology}, volume = {13}, journal = {BMC biotechnology}, number = {22}, publisher = {BioMed Central}, address = {London}, issn = {1472-6750}, doi = {10.1186/1472-6750-13-51}, pages = {10}, year = {2013}, abstract = {Background: A promising way in diagnostic and therapeutic applications is the development of peptide amphiphiles (PAs). Peptides with a palmitic acid alkylchain were designed and characterized to study the effect of the structure modifications on self-assembling capabilities and the multiple binding capacity to hemagglutinin (HA), the surface protein of influenza virus type A. The peptide amphiphiles consists of a hydrophilic headgroup with a biological functionality of the peptide sequence and a chemically conjugated hydrophobic tail. In solution they self-assemble easily to micelles with a hydrophobic core surrounded by a closely packed peptide-shell. Results: In this study the effect of a multiple peptide binding partner to the receptor binding site of HA could be determined with surface plasmon resonance measurements. The applied modification of the peptides causes signal amplification in relationship to the unmodified peptide wherein the high constant specificity persists. The molecular assembly of the peptides was characterized by the determination of critical micelle concentration (CMC) with concentration of 10(-5) M and the colloidal size distribution. Conclusion: The modification of the physico-chemical parameters by producing peptide amphiphiles form monomeric structures which enhances the binding affinity and allows a better examination of the interaction with the virus surface protein hemagglutinin.}, language = {en} } @article{SchmitzHertzbergMakLaietal.2013, author = {Schmitz-Hertzberg, Sebastian-Tim and Mak, Wing Cheung and Lai, Kwok Kei and Teller, Carsten and Bier, Frank Fabian}, title = {Multifactorial design of Poly(D, L-lactic-co-glycolic acid) capsules with various release properties for differently sized filling agents}, series = {Journal of applied polymer science}, volume = {130}, journal = {Journal of applied polymer science}, number = {6}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0021-8995}, doi = {10.1002/app.39537}, pages = {4219 -- 4228}, year = {2013}, abstract = {The hydrolytic degradation and corresponding content release of capsules made of poly(d,l-lactic-co-glycolic acid) (PLGA) strongly depends on the composition and material properties of the initially applied copolymer. Consecutive or simultaneous release from capsule batches of combinable material compositions, therefore, offers high control over the bioavailability of an encapsulated drug. The keynote of this study was the creation of a superordinated database that addressed the correlation between the release kinetics of filling agents with different molecular weights from PLGA capsules of alternating composition. Fluorescein isothiocyanate (FITC)-dextran (with molecular weights of 4, 40, and 2000 kDa) was chosen as a model analyte, whereas the copolymers were taken from various 50:50 PLGA, 75:25 PLGA, and polylactide blends. With reference to recent publications, the capsule properties, such as the size, morphology, and encapsulation efficiency, were further modified during production. Hence, uniform microdisperse and polydisperse submicrometer nanocapsules were prepared by two different water-in-oil-in-water emulsification techniques, and additional effects on the size and morphology were achieved by capsule solidification in two different sodium salt buffers. The qualitative and quantitative examination of the physical capsule properties was performed by confocal laser scanning microscopy, scanning electron microscopy, and Coulter counting techniques to evaluate the capsule size distribution and the morphological appearance of the different batches. The corresponding agent release was quantified by fluorescence measurement of the FITC-dextran in the incubation media and by the direct measurement of the capsule brightness via fluorescence microscopy. In summary, the observed agent release showed a highly controllable flexibility depending on the PLGA blends, preparation methods, and molecular weight of the used filling substances. (c) 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4219-4228, 2013}, language = {en} } @article{GriessnerHartigChristmannetal.2010, author = {Grießner, Matthias and Hartig, Dave and Christmann, Alexander and Ehrentreich-F{\"o}rster, Eva and Warsinke, Axel and Bier, Frank Fabian}, title = {Surface regeneration of microfluidic microarray printheads through plasma techniques}, issn = {0960-1317}, doi = {10.1088/0960-1317/20/3/037002}, year = {2010}, abstract = {This work describes a method for surface regeneration of microfluidic microarray printheads through plasma techniques. Modification procedures were chosen in a way to obtain high reproducibility with a minimum of time consumption. The idea behind this is a complete regeneration of a microarray printhead before or after usage to achieve best printing results over a typical print job. A sequence of low-pressure oxygen-plasma and plasma polymerization with hexamethyldisiloxane (HMDSO) was used to regenerate printheads. Proof of the concept is given through quality control performed with a spotter implemented CCD camera, contact angle measurements and a typical hybridization experiment. Stable printing results were obtained over 3000 activations showing that the presented method is suitable for treatment of microarray printheads.}, language = {en} } @article{ReissHoelzelBier2009, author = {Reiss, Edda and Hoelzel, Ralph and Bier, Frank Fabian}, title = {Synthesis and stretching of rolling circle amplification products in a flow-through system}, issn = {1613-6810}, doi = {10.1002/smll.200900319}, year = {2009}, abstract = {Enzymatic isothermal rolling circle amplification (RCA) produces long concatemeric single-stranded DNA (ssDNA) molecules if a small circular ssDNA molecule is applied as the template. A method is presented here in which the RCA reaction is carried out in a flow-through system, starting from isolated surface-tethered DNA primers. This approach combines gentle fluidic handling of the single-stranded RCA products, such as staining or stretching via a receding meniscus, with the option of simultaneous (fluorescence) microscopic observation. It is shown that the stretched and surface-attached RCA products are accessible for hybridization of complementary oligonucleotides, which demonstrates their addressability by complementary base pairing. The long RCA products should be well suited to bridge the gap between biomolecular nanoscale building-blocks and structures at the micro- and macroscale, especially at the single- molecule level presented here.}, language = {en} } @article{GriessnerBroekerLehmannetal.2009, author = {Grießner, Matthias and Broeker, Patrick and Lehmann, Andr{\´e} and Ehrentreich-F{\"o}rster, Eva and Bier, Frank Fabian}, title = {Detection of angiotensin II type 1 receptor ligands by a cell-based assay}, issn = {1618-2642}, doi = {10.1007/s00216-009-3074-4}, year = {2009}, abstract = {This work describes a cell-based assay that does not depend on radioactivity or laboratory animals for the detection of ligands of angiotensin II type 1 receptor (AT(1)R). The assay makes use of stable transfected Chinese hamster ovary cells (CHO-AT(1)R) expressing the AT(1)R. A sequential saturation assay principle was used in which receptor binding sites of the CHO-AT(1)R cells are blocked by the analyte in a concentration-dependent manner. Afterwards, TAMRA-angiotensin II, a fluorescence-labeled ligand, was added to bind to the remaining free binding sites of the receptor. In consequence, the fluorescence signal determined is inversely proportional to the concentration of the analyte.}, language = {en} } @article{AndresenvonNickischRosenegkBier2009, author = {Andresen, Dennie and von Nickisch-Rosenegk, Markus and Bier, Frank Fabian}, title = {Helicase-dependent amplification : use in OnChip amplification and potential for point-of-care diagnostics}, issn = {1473-7159}, doi = {10.1586/erm.09.46}, year = {2009}, abstract = {Isothermal amplification technologies are emerging on the horizon that could have the potential to pose as alternatives to PCR in terms of sensitivity and ease of use. One of the most recent isothermal technologies is helicase- dependent amplification (HDA). This technology uses the helicase's capability to disrupt the hydrogen bonds of a Watson-Crick base pair in order to separate dsDNA. A denaturation step, as is used in PCR, is no longer required. This gives rise to new, less expensive and less complicated designs for point-of-care devices and 'Lab on Chip' systems. Helicase-dependent OnChip-amplification (OnChip-HDA) is a further step into this direction as it integrates the HDA technology with microarray technology and its power of multiplexing. This special report will give an overview on the HDA and OnChip-HDA technology, and its potential for point-of-care diagnostics.}, language = {en} } @article{AndresenvonNickischRosenegkBier2009, author = {Andresen, Dennie and von Nickisch-Rosenegk, Markus and Bier, Frank Fabian}, title = {Helicase dependent OnChip-amplification and its use in multiplex pathogen detection}, issn = {0009-8981}, doi = {10.1016/j.cca.2009.03.021}, year = {2009}, abstract = {Background: The need for fast, specific and sensitive multiparametric detection methods is an ever growing demand in molecular diagnostics. Here we report on a newly developed method, the helicase dependent Onchip amplification (OnChip-HDA). This approach integrates the analysis and detection in one single reaction thus leading to time and cost savings in multiparametric analysis. Methods: HDA is an isothermal amplification method that is not depending on thermocycling as known from PCR due to the helicases' ability to unwind DNA double-strands. We have combined the HDA with microarray based detection, making it suitable for multiplex detection. As an example we used the Onchip HDA in single and multiplex amplifications for the detection of the two pathogens N. gonorrhoeae and S. aureus directly on surface bound primers. Results: We have successfully shown the OnChip-HDA and applied it for single- and duplex- detection of the pathogens N. gonorrhoeae and S. aureus. Conclusion: We have developed a new method, the OnChip-HDA for the multiplex detection of pathogens. Its simplicity in reaction setup and potential for miniaturization and multiparametric analysis is advantageous for the integration in miniaturized Lab on Chip systems, e.g. needed in point of care diagnostics.}, language = {en} } @article{AndresenGrotzingerZarseetal.2006, author = {Andresen, Heiko and Grotzinger, Carsten and Zarse, Kim and Kreuzer, Oliver Johannes and Ehrentreich-F{\"o}rster, Eva and Bier, Frank Fabian}, title = {Functional peptide microarrays for specific and sensitive antibody diagnostics}, issn = {1615-9853}, doi = {10.1002/pmic.200500343}, year = {2006}, abstract = {Peptide microarrays displaying biologically active small synthetic peptides in a high-density format provide an attractive technology to probe complex samples for the presence and/or function of protein analytes. We present a new approach for manufacturing functional peptide microarrays for molecular immune diagnostics. Our method relies on the efficiency of site-specific solution-phase coupling of biotinylated synthetic peptides to NeutrAvidin (NA) and localized microdispensing of peptide-NA-complexes onto activated glass surfaces. Antibodies are captured in a sandwich manner between surface immobilized peptide probes and fluorescence-labeled secondary antibodies. Our work includes a total of 54 peptides derived from immunodominant linear epitopes of the T7 phage capsid protein, Herpes simplex virus glycoprotein D, c-myc protein, and three domains of the Human coronavirus polymerase polyprotein and their cognate mAbs. By using spacer molecules of different type and length for NA-mediated peptide presentation, we show that the incorporation of a minimum spacer length is imperative for antibody binding, whereas the peptide immobilization direction has only secondary importance for antibody affinity and binding. We further demonstrate that the peptide array is capable of detecting low-picomolar concentrations of mAbs in buffered solutions and diluted human serum with high specificity}, language = {en} } @article{AndresenGroetzingerZarseetal.2006, author = {Andresen, Heiko and Gr{\"o}tzinger, Carsten and Zarse, Kim and Birringer, Marc and Hessenius, Carsten and Kreuzer, Oliver Johannes and Ehrentreich-F{\"o}rster, Eva and Bier, Frank Fabian}, title = {Peptide microarrays with site-specifically immobilized synthetic peptides for antibody diagnostics}, issn = {0925-4005}, doi = {10.1016/j.snb.2005.07.033}, year = {2006}, abstract = {Peptide microarrays bear the potential to discover molecular recognition events on protein level, particularly in the field of molecular immunology, in a manner and with an efficiency comparable to the performance of DNA microarrays. We developed a novel peptide microarray platform for the detection of antibodies in liquid samples. The system comprises site-specific solution phase coupling of biotinylated peptides to NeutrAvidin, localized microdispensing of peptide-NeutrAvidin conjugates onto activated glass slides and a fluorescence immuno sandwich assay format for antibody capture and detection. Our work includes synthetic peptides deduced from amino acid sequences of immunodominant linear epitopes, such as the T7 phage capsid protein, Herpes simplex virus glycoprotein D, c-myc protein and three domains of the Human coronavirus 229E polymerase polyprotein. We demonstrate that our method produces peptide arrays with excellent spot morphology which are capable of specific and sensitive detection of monoclonal antibodies from fluid samples.}, language = {en} } @article{BierSchellerKlingbeiletal.1993, author = {Bier, Frank Fabian and Scheller, Frieder W. and Klingbeil, Mandy and Oßwald, U.}, title = {Biosensoren und Teststreifen f{\"u}r die Umwelt- und Lebensmittelanalytik : eine {\"U}bersicht}, year = {1993}, language = {de} } @article{SchellerBierNeumann1994, author = {Scheller, Frieder W. and Bier, Frank Fabian and Neumann, B.}, title = {Bioindikation in aquatischen {\"O}kosystemen : Bioindikation in limnischen und k{\"u}stennahen {\"O}kosystemen ; Grundlagen, Verfahren und Methoden}, publisher = {Fischer}, address = {Jena}, pages = {S. 380 - 386}, year = {1994}, language = {de} } @article{SchellerMakowerGhindilisetal.1995, author = {Scheller, Frieder W. and Makower, Alexander and Ghindilis, A. L. and Bier, Frank Fabian and Ehrentreich-F{\"o}rster, Eva and Wollenberger, Ursula and Bauer, Christian G. and Micheel, Burkhard and Pfeiffer, Dorothea and Szeponik, Jan and Michael, N. and Kaden, H.}, title = {Enzyme sensors for subnanomolar concentrations}, year = {1995}, language = {en} } @article{JinWollenbergerBieretal.1995, author = {Jin, Wen and Wollenberger, Ursula and Bier, Frank Fabian and Scheller, Frieder W.}, title = {Construction and characterization of multi-layer-enzyme electrode : covalent binding of quinoprotein glucose dehydrogenase onto gold electrodes}, year = {1995}, language = {en} } @article{GhindilisMakowerBaueretal.1995, author = {Ghindilis, A. L. and Makower, Alexander and Bauer, Christian G. and Bier, Frank Fabian and Scheller, Frieder W.}, title = {Determination of p-aminophenol and catecholamines at picomolar concentrations based on recycling enzyme amplification}, year = {1995}, language = {en} } @article{SongBierScheller1995, author = {Song, Min Ik and Bier, Frank Fabian and Scheller, Frieder W.}, title = {A method to detect superoxide radicals using teflon membrane and superoxide dismutase}, year = {1995}, language = {en} } @article{SchellerSchubertBier1995, author = {Scheller, Frieder W. and Schubert, Florian and Bier, Frank Fabian}, title = {Vom Biosensor zur Nanobiotechnologie}, year = {1995}, language = {de} } @article{SchellerBierPfeiffer1995, author = {Scheller, Frieder W. and Bier, Frank Fabian and Pfeiffer, Dorothea}, title = {Biosensoren : Grundlagen und Anwendungen}, year = {1995}, language = {de} } @article{SchellerMakowerBieretal.1995, author = {Scheller, Frieder W. and Makower, Alexander and Bier, Frank Fabian and Wollenberger, Ursula and Ghindilis, A. L. and Eremenko, A. V. and Pfeiffer, Dorothea}, title = {Enzymsensoren zur Bestimmung subnanomolarer Konzentrationen}, year = {1995}, language = {de} } @article{BauerEremenkoEhrentreichFoersteretal.1996, author = {Bauer, Christian G. and Eremenko, A. V. and Ehrentreich-F{\"o}rster, Eva and Bier, Frank Fabian and Makower, Alexander and Halsall, H. B. and Heineman, W. R. and Scheller, Frieder W.}, title = {Zeptomole-detecting biosensor for alkaline phosphatase in an electroche mical immunoassay for 2,4- dichlorophenoacetic acid}, year = {1996}, language = {en} } @article{BierEhrentreichFoersterBaueretal.1996, author = {Bier, Frank Fabian and Ehrentreich-F{\"o}rster, Eva and Bauer, Christian G. and Scheller, Frieder W.}, title = {High sensitive competitive immunodetection of 2,4-dichlorophenoxyacetic acid using enzymatic amplification with electrochemical detection}, year = {1996}, language = {en} } @article{BierEhrentreichFoersterSchelleretal.1996, author = {Bier, Frank Fabian and Ehrentreich-F{\"o}rster, Eva and Scheller, Frieder W. and Makower, Alexander and Eremenko, A. V. and Wollenberger, Ursula and Bauer, Christian G. and Pfeiffer, Dorothea and Micheel, Burkhard}, title = {Ultrasensitive biosensors}, year = {1996}, language = {en} } @article{BierEhrentreichFoersterMakoweretal.1996, author = {Bier, Frank Fabian and Ehrentreich-F{\"o}rster, Eva and Makower, Alexander and Scheller, Frieder W.}, title = {An enzymatic amplification cycle for high sensitive immunoassay}, year = {1996}, language = {en} } @article{BierScheller1996, author = {Bier, Frank Fabian and Scheller, Frieder W.}, title = {Label-free observation of DNA-hybridisation and endonuclease activity on a wave guide surface using a grating coupler}, year = {1996}, language = {en} } @article{BierEhrentreichFoersterScheller1996, author = {Bier, Frank Fabian and Ehrentreich-F{\"o}rster, Eva and Scheller, Frieder W.}, title = {Amplifying bienzyme cycle-linked immunoassays for determination of 2,4- dichlorphenoxyacetic acid}, year = {1996}, language = {en} } @article{JinWollenbergerBieretal.1996, author = {Jin, Wen and Wollenberger, Ursula and Bier, Frank Fabian and Makower, Alexander and Schiller, Frieder W.}, title = {Electron transfer between cytochrome c and copper enzymes}, year = {1996}, language = {en} } @article{BierFuerste1997, author = {Bier, Frank Fabian and F{\"u}rste, J. P.}, title = {Nucleic acid based sensors}, year = {1997}, language = {en} } @article{BierEhrentreichFoersterDoellingetal.1997, author = {Bier, Frank Fabian and Ehrentreich-F{\"o}rster, Eva and D{\"o}lling, R. and Eremenko, A. V. and Scheller, Frieder W.}, title = {A redox-label immunosensor on basis of a bi-enzyme electrode}, year = {1997}, language = {en} } @article{SchellerBierGajovic1997, author = {Scheller, Frieder W. and Bier, Frank Fabian and Gajovic, Nenad}, title = {Biosensoren und Teststreifen f{\"u}r die Umwelt- und Lebensmittelanalytik}, year = {1997}, language = {de} } @article{StoeckleinMakowerBieretal.1997, author = {St{\"o}cklein, Walter F. M. and Makower, Alexander and Bier, Frank Fabian and Scheller, Frieder W.}, title = {Enzyme sensors and enzyme amplifification systems}, year = {1997}, language = {en} } @article{MakowerBarminMorzunovaetal.1997, author = {Makower, Alexander and Barmin, Anatoli V. and Morzunova, T. and Eremenko, Arkadi V. and Bier, Frank Fabian and Scheller, Frieder W.}, title = {Affinity enzymomoetric assay for detection of organophosphorus compounds}, year = {1997}, language = {en} } @article{BierFuersteKleinjungetal.1997, author = {Bier, Frank Fabian and F{\"u}rste, J. P. and Kleinjung, Frank and Erdmann, V. A. and Scheller, Frieder W.}, title = {Nukleins{\"a}uren als Basis f{\"u}r Biosensoren}, year = {1997}, language = {de} } @article{BierKleinjungScheller1997, author = {Bier, Frank Fabian and Kleinjung, Frank and Scheller, Frieder W.}, title = {Real time measurement of nucleic acid hybridization using evanescent wave sensors - step towards the genosensor}, year = {1997}, language = {en} } @phdthesis{Bier1997, author = {Bier, Frank Fabian}, title = {Biomolekulare Erkennung und Signaltransduktion in Affinit{\"a}tssensoren}, address = {Potsdam}, pages = {97, A189 S. : graph. Darst.}, year = {1997}, language = {de} } @article{SchellerKleinjungBieretal.1998, author = {Scheller, Frieder W. and Kleinjung, Frank and Bier, Frank Fabian and Markower, Alexander and Neumann, Barbara and Wollenberger, Ursula and Kurochkin, Iliya N. and Eremenko, Arkadi V. and Barmin, Anatoli V. and Klußmann, Sven and F{\"u}rste, Jens-Peter and Erdmann, Volker A. and Mansuy, D.}, title = {New recognition elements in biosensing}, year = {1998}, language = {en} } @article{KleinjungKlussmannErdmannetal.1998, author = {Kleinjung, Frank and Klußmann, S. and Erdmann, V. A. and Scheller, Frieder W. and F{\"u}rste, J. P. and Bier, Frank Fabian}, title = {Novel binders in biosensorics : hight affinity RNA for smal analytes}, year = {1998}, language = {en} } @article{SchmidtMatthesSchelleretal.2001, author = {Schmidt, Peter Michael and Matthes, E. and Scheller, Frieder W. and Bier, Frank Fabian}, title = {Nachweis der Telomeraseaktivit{\"a}t in Zellkulturen mittels eines faseroptischen Sensors}, year = {2001}, language = {de} } @article{SchellerBauerMarkoweretal.2001, author = {Scheller, Frieder W. and Bauer, Christian G. and Markower, Alexander and Wollenberger, Ursula and Warsinke, Axel and Bier, Frank Fabian}, title = {Coupling of immunoassays with enzymatic recycling electrodes}, year = {2001}, language = {en} } @article{SchellerBier2002, author = {Scheller, Frieder W. and Bier, Frank Fabian}, title = {Trends in der Bioanalytik}, year = {2002}, language = {de} } @article{SchellerBauerMakoweretal.2002, author = {Scheller, Frieder W. and Bauer, Christian G. and Makower, Alexander and Wollenberger, Ursula and Warsinke, Axel and Bier, Frank Fabian}, title = {Immunoassays using enzymatic amplification electrodes}, isbn = {0-7484-0791-X}, year = {2002}, language = {en} } @book{WollenbergerRennebergBieretal.2003, author = {Wollenberger, Ursula and Renneberg, Reinhard and Bier, Frank Fabian and Scheller, Frieder W.}, title = {Analytische Biochemie : eine praktische Einf{\"u}hrung in das Messen mit Biomolek{\"u}len}, publisher = {John Wiley \& Sons}, address = {Hoboken}, isbn = {3-527-30166-6}, pages = {222 S.}, year = {2003}, language = {de} } @article{SchellerBier2003, author = {Scheller, Frieder W. and Bier, Frank Fabian}, title = {Biosensoren}, year = {2003}, language = {de} } @article{EhrentreichFoersterSchellerBier2003, author = {Ehrentreich-F{\"o}rster, Eva and Scheller, Frieder W. and Bier, Frank Fabian}, title = {Detection of progesterone in whole blood samples}, year = {2003}, abstract = {The progesterone concentration in blood samples can be utilised as a marker for the diagnosis of early pregnancy, endocrinopathy and virilism. Here, we describe a method for progesterone detection and measurement in whole blood samples by a surface sensitive biosensor used in conjunction with an integrated optical grating coupler. This device determines refractive index changes near the biosensor's surface. Hence, biological species bound to a surface layer can be measured in real-time without any label. For the measurements, we have modified the indirect competitive immonoassay principle. The concentration of the progesterone antibody was kept at 1 µg/ml. Progesterone concentration was determined in buffer solution and whole blood in a range between 0.005 and 10 ng/ml. The detection limit was determined to be 3 pM. The relative standard deviation was calculated to be 3.5\%.}, language = {en} } @article{SchellerBier2004, author = {Scheller, Frieder W. and Bier, Frank Fabian}, title = {Analytical Biochemistry (Editorial)}, year = {2004}, language = {en} } @article{SteffenvonNickischRosenegkBier2005, author = {Steffen, Jenny and von Nickisch-Rosenegk, Markus and Bier, Frank Fabian}, title = {In vitro transcription of a whole gene on a surface-coupled template}, issn = {1473-0189}, year = {2005}, abstract = {An artificial gene was constructed combining the T7 promoter and terminator with the EGFP-gene from the plasmid pEGFP. The functionality of the construct was shown by in vitro translation. The gene-construct was immobilised on a planar glass surface. The transcription was performed on the immobilised gene and mRNA was determined by RT-PCR. Multiple use of the immobilised gene was demonstrated}, language = {en} } @article{HeiseBier2005, author = {Heise, Christian and Bier, Frank Fabian}, title = {Immobilization of DNA on microarrays}, year = {2005}, abstract = {Microarrays are new analytical devices that allow the parallel and simultaneous detection of thousands of target compounds. Microarrays, also called DNA chips, are widely used in gene expression, the genotyping of individuals, point mutations, detection of single nucleotide polymorphisms, and short tandem repeats. Microarrays have highly specific base-pair interactions with labeled complementary strands, which makes this technology to a powerful analytical device for monitoring whole genomes. In this article, we provide a survey of the common microarray manufacturing methods, from the selection of support material to surface structuring, immobilization and hybridization, and finally the detection with labeled complementary strands. Special attention is given to the immobilization of single strands, since fast chemical reactions, the creation of homogeneous surface functionalities as well as an oriented coupling are crucial pre-conditions for a good spot morphology and microarrays of high quality}, language = {en} }