@article{CasertaZhangYarmanetal.2021,
author = {Caserta, Giorgio and Zhang, Xiaorong and Yarman, Aysu and Supala, Eszter and Wollenberger, Ulla and Gyurcs{\´a}nyi, R{\´o}bert E. and Zebger, Ingo and Scheller, Frieder W.},
title = {Insights in electrosynthesis, target binding, and stability of peptide-imprinted polymer nanofilms},
series = {Electrochimica acta : the journal of the International Society of Electrochemistry (ISE)},
volume = {381},
journal = {Electrochimica acta : the journal of the International Society of Electrochemistry (ISE)},
publisher = {Elsevier},
address = {New York, NY [u.a.]},
issn = {0013-4686},
doi = {10.1016/j.electacta.2021.138236},
pages = {8},
year = {2021},
abstract = {Molecularly imprinted polymer (MIP) nanofilms have been successfully implemented for the recognition of different target molecules: however, the underlying mechanistic details remained vague. This paper provides new insights in the preparation and binding mechanism of electrosynthesized peptide-imprinted polymer nanofilms for selective recognition of the terminal pentapeptides of the beta-chains of human adult hemoglobin, HbA, and its glycated form HbA1c. To differentiate between peptides differing solely in a glucose adduct MIP nanofilms were prepared by a two-step hierarchical electrosynthesis that involves first the chemisorption of a cysteinyl derivative of the pentapeptide followed by electropolymerization of scopoletin. This approach was compared with a random single-step electrosynthesis using scopo-letin/pentapeptide mixtures. Electrochemical monitoring of the peptide binding to the MIP nanofilms by means of redox probe gating revealed a superior affinity of the hierarchical approach with a Kd value of 64.6 nM towards the related target. Changes in the electrosynthesized non-imprinted polymer and MIP nanofilms during chemical, electrochemical template removal and rebinding were substantiated in situ by monitoring the characteristic bands of both target peptides and polymer with surface enhanced infrared absorption spectroscopy. This rational approach led to MIPs with excellent selectivity and provided key mechanistic insights with respect to electrosynthesis, rebinding and stability of the formed MIPs.},
language = {en}
}
@article{YarmanKurbanoğluZebgeretal.2021,
author = {Yarman, Aysu and Kurbanoğlu, Sevin{\c{c}} and Zebger, Ingo and Scheller, Frieder W.},
title = {Simple and robust},
series = {Sensors and actuators : B, Chemical : an international journal devoted to research and development of chemical transducers},
volume = {330},
journal = {Sensors and actuators : B, Chemical : an international journal devoted to research and development of chemical transducers},
publisher = {Elsevier Science},
address = {Amsterdam [u.a.]},
issn = {0925-4005},
doi = {10.1016/j.snb.2020.129369},
pages = {12},
year = {2021},
abstract = {A spectrum of 7562 publications on Molecularly Imprinted Polymers (MIPs) has been presented in literature within the last ten years (Scopus, September 7, 2020). Around 10 \% of the papers published on MIPs describe the recognition of proteins. The straightforward synthesis of MIPs is a significant advantage as compared with the preparation of enzymes or antibodies. MIPs have been synthesized from only one up to six functional monomers while proteins are made up of 20 natural amino acids. Furthermore, they can be synthesized against structures of low immunogenicity and allow multi-analyte measurements via multi-target synthesis. Electrochemical methods allow simple polymer synthesis, removal of the template and readout. Among the different sensor configurations electrochemical MIP-sensors provide the broadest spectrum of protein analytes. The sensitivity of MIP-sensors is sufficiently high for biomarkers in the sub-nanomolar region, nevertheless the cross-reactivity of highly abundant proteins in human serum is still a challenge. MIPs for proteins offer innovative tools not only for clinical and environmental analysis, but also for bioimaging, therapy and protein engineering.},
language = {en}
}
@article{ZhangCasertaYarmanetal.2021,
author = {Zhang, Xiaorong and Caserta, Giorgio and Yarman, Aysu and Supala, Eszter and Tadjoung Waffo, Armel Franklin and Wollenberger, Ulla and Gyurcsanyi, Robert E. and Zebger, Ingo and Scheller, Frieder W.},
title = {"Out of Pocket" protein binding},
series = {Chemosensors},
volume = {9},
journal = {Chemosensors},
number = {6},
publisher = {MDPI},
address = {Basel},
issn = {2227-9040},
doi = {10.3390/chemosensors9060128},
pages = {13},
year = {2021},
abstract = {The epitope imprinting approach applies exposed peptides as templates to synthesize Molecularly Imprinted Polymers (MIPs) for the recognition of the parent protein. While generally the template protein binding to such MIPs is considered to occur via the epitope-shaped cavities, unspecific interactions of the analyte with non-imprinted polymer as well as the detection method used may add to the complexity and interpretation of the target rebinding. To get new insights on the effects governing the rebinding of analytes, we electrosynthesized two epitope-imprinted polymers using the N-terminal pentapeptide VHLTP-amide of human hemoglobin (HbA) as the template. MIPs were prepared either by single-step electrosynthesis of scopoletin/pentapeptide mixtures or electropolymerization was performed after chemisorption of the cysteine extended VHLTP peptide. Rebinding of the target peptide and the parent HbA protein to the MIP nanofilms was quantified by square wave voltammetry using a redox probe gating, surface enhanced infrared absorption spectroscopy, and atomic force microscopy. While binding of the pentapeptide shows large influence of the amino acid sequence, all three methods revealed strong non-specific binding of HbA to both polyscopoletin-based MIPs with even higher affinities than the target peptides.},
language = {en}
}
@article{BognarSupalaYarmanetal.2022,
author = {Bogn{\´a}r, Zs{\´o}fia and Supala, Eszter and Yarman, Aysu and Zhang, Xiaorong and Bier, Frank Fabian and Scheller, Frieder W. and Gyurcsanyi, R{\´o}bert E.},
title = {Peptide epitope-imprinted polymer microarrays for selective protein recognition},
series = {Chemical science / RSC, Royal Society of Chemistry},
volume = {13},
journal = {Chemical science / RSC, Royal Society of Chemistry},
number = {5},
publisher = {Royal Society of Chemistry},
address = {Cambridge},
issn = {2041-6539},
doi = {10.1039/d1sc04502d},
pages = {1263 -- 1269},
year = {2022},
abstract = {We introduce a practically generic approach for the generation of epitope-imprinted polymer-based microarrays for protein recognition on surface plasmon resonance imaging (SPRi) chips. The SPRi platform allows the subsequent rapid screening of target binding kinetics in a multiplexed and label-free manner. The versatility of such microarrays, both as synthetic and screening platform, is demonstrated through developing highly affine molecularly imprinted polymers (MIPs) for the recognition of the receptor binding domain (RBD) of SARS-CoV-2 spike protein. A characteristic nonapeptide GFNCYFPLQ from the RBD and other control peptides were microspotted onto gold SPRi chips followed by the electrosynthesis of a polyscopoletin nanofilm to generate in one step MIP arrays. A single chip screening of essential synthesis parameters, including the surface density of the template peptide and its sequence led to MIPs with dissociation constants (K-D) in the lower nanomolar range for RBD, which exceeds the affinity of RBD for its natural target, angiotensin-convertase 2 enzyme. Remarkably, the same MIPs bound SARS-CoV-2 virus like particles with even higher affinity along with excellent discrimination of influenza A (H3N2) virus. While MIPs prepared with a truncated heptapeptide template GFNCYFP showed only a slightly decreased affinity for RBD, a single mismatch in the amino acid sequence of the template, i.e. the substitution of the central cysteine with a serine, fully suppressed the RBD binding.},
language = {en}
}
@article{OzcelikayKurbanogluYarmanetal.2020,
author = {Ozcelikay, Goksu and Kurbanoglu, Sevinc and Yarman, Aysu and Scheller, Frieder W. and Ozkan, Sibel A.},
title = {Au-Pt nanoparticles based molecularly imprinted nanosensor for electrochemical detection of the lipopeptide antibiotic drug Daptomycin},
series = {Sensors and actuators : B, Chemical},
volume = {320},
journal = {Sensors and actuators : B, Chemical},
publisher = {Elsevier Science},
address = {Amsterdam},
issn = {0925-4005},
doi = {10.1016/j.snb.2020.128285},
pages = {7},
year = {2020},
abstract = {In this work, a novel electrochemical molecularly imprinted polymer (MIP) sensor for the detection of the lipopeptide antibiotic Daptomycin (DAP) is presented which integrates gold decorated platinum nanoparticles (Au-Pt NPs) into the nanocomposite film. The sensor was prepared by electropolymerization of o-phenylenediamine (o-PD) in the presence of DAP using cyclic voltammetry. Cyclic voltammetry and differential pulse voltammetry were applied to follow the changes in the MIP-layer related to rebinding and removal of the target DAP by using the redox marker [Fe(CN)(6)](3-/4-). Under optimized operational conditions, the MIP/Au-Pt NPs/ GCE nanosensor exhibits a linear response in the range of 1-20 pM towards DAP. The limit of detection and limit of quantification were determined to be 0.161pM +/- 0.012 and 0.489pM +/- 0.012, respectively. The sensitivity towards the antibiotics Vancomycin and Erythromycin and the amino acids glycine and tryptophan was below 7 percent as compared with DAP. Moreover, the nanosensor was also successfully used for the detection of DAP in deproteinated human serum samples.},
language = {en}
}
@misc{YarmanScheller2020,
author = {Yarman, Aysu and Scheller, Frieder W.},
title = {How reliable is the electrochemical readout of MIP sensors?},
series = {Sensors},
volume = {20},
journal = {Sensors},
number = {9},
publisher = {MDPI},
address = {Basel},
issn = {1424-8220},
doi = {10.3390/s20092677},
pages = {23},
year = {2020},
abstract = {Electrochemical methods offer the simple characterization of the synthesis of molecularly imprinted polymers (MIPs) and the readouts of target binding. The binding of electroinactive analytes can be detected indirectly by their modulating effect on the diffusional permeability of a redox marker through thin MIP films. However, this process generates an overall signal, which may include nonspecific interactions with the nonimprinted surface and adsorption at the electrode surface in addition to (specific) binding to the cavities. Redox-active low-molecular-weight targets and metalloproteins enable a more specific direct quantification of their binding to MIPs by measuring the faradaic current. The in situ characterization of enzymes, MIP-based mimics of redox enzymes or enzyme-labeled targets, is based on the indication of an electroactive product. This approach allows the determination of both the activity of the bio(mimetic) catalyst and of the substrate concentration.},
language = {en}
}
@article{KurbanogluYarman2020,
author = {Kurbanoglu, Sevinc and Yarman, Aysu},
title = {Simultaneous determination of hydrochlorothiazide and irbesartan from pharmaceutical dosage forms with RP-HPLC},
series = {Turkish journal of pharmaceutical sciences},
volume = {17},
journal = {Turkish journal of pharmaceutical sciences},
number = {5},
publisher = {Turkish Pharmacists Association},
address = {{\c{C}}ankaya-Ankara},
issn = {1304-530X},
doi = {10.4274/tjps.galenos.2019.76094},
pages = {523 -- 527},
year = {2020},
abstract = {Objectives: In this work, a simple and rapid liquid chromatographic method for the simultaneous determination of irbesartan (IRBE) and hydrochlorothiazide (HCT) was developed and validated by reverse phase high performance liquid chromatography (RP-HPLC).
Materials and Methods: Experimental conditions such as different buffer solutions, various pH values, temperature, composition of the mobile phase, and the effect of flow rate were optimized.
Results: The developed RP-HPLC method for these antihypertensive agents was wholly validated and IRBE was detected in the linear range of 0.1-25 mu g mL(-1) and HCT was detected in the linear range of 0.25-25 mu g mL(-1). Moreover, the suggested chromatographic technique was successfully applied for the determination of the drugs in human serum and pharmaceutical dosage forms with limit of detection values of 0.008 mu g mL(-1) for IRBE and 0.012 mu g mL(-1) for HCT.
Conclusion: The proposed rapid analysis method of these antihypertensive drugs can be easily used and applied by pharmaceutical companies for which the analysis time is important.},
language = {en}
}
@misc{YarmanJetzschmannNeumannetal.2017,
author = {Yarman, Aysu and Jetzschmann, Katharina J. and Neumann, Bettina and Zhang, Xiaorong and Wollenberger, Ulla and Cordin, Aude and Haupt, Karsten and Scheller, Frieder W.},
title = {Enzymes as Tools in MIP-Sensors},
series = {Chemosensors},
volume = {5},
journal = {Chemosensors},
publisher = {MDPI},
address = {Basel},
issn = {2227-9040},
doi = {10.3390/chemosensors5020011},
pages = {16},
year = {2017},
abstract = {Molecularly imprinted polymers (MIPs) have the potential to complement antibodies in bioanalysis, are more stable under harsh conditions, and are potentially cheaper to produce. However, the affinity and especially the selectivity of MIPs are in general lower than those of their biological pendants. Enzymes are useful tools for the preparation of MIPs for both low and high-molecular weight targets: As a green alternative to the well-established methods of chemical polymerization, enzyme-initiated polymerization has been introduced and the removal of protein templates by proteases has been successfully applied. Furthermore, MIPs have been coupled with enzymes in order to enhance the analytical performance of biomimetic sensors: Enzymes have been used in MIP-sensors as tracers for the generation and amplification of the measuring signal. In addition, enzymatic pretreatment of an analyte can extend the analyte spectrum and eliminate interferences.},
language = {en}
}
@article{Yarman2017,
author = {Yarman, Aysu},
title = {Development of a molecularly imprinted polymer-based electrochemical sensor for tyrosinase},
series = {Turkish journal of chemistry},
volume = {42},
journal = {Turkish journal of chemistry},
number = {2},
publisher = {T{\"u}rkiye Bilimsel ve Teknik Ara{\c{s}}t{\i}rma Kurumu},
address = {Ankara},
issn = {1300-0527},
doi = {10.3906/kim-1708-68},
pages = {346 -- 354},
year = {2017},
abstract = {For the first time a molecularly imprinted polymer (MIP)-based sensor for tyrosinase is described. This sensor is based on the electropolymerization of scopoletin or o-phenylenediamine in the presence of tyrosinase from mushrooms, which has a high homology to the human enzyme. The template was removed either by treatment with proteinase Kor by alkaline treatment. The measuring signal was generated either by measuring the formation of a product by the target enzyme or by evaluation of the permeability of the redox marker ferricyanide. The o-phenylenediamine-based MIP sensor has a linear measuring range up to 50 nM of tyrosinase with a limit of detection of 3.97 nM (R 2 = 0.994) and shows good discrimination towards other proteins, e.g., bovine serum albumin and cytochrome c.},
language = {en}
}
@misc{YarmanKurbanogluJetzschmannetal.2018,
author = {Yarman, Aysu and Kurbanoglu, Sevinc and Jetzschmann, Katharina J. and Ozkan, Sibel A. and Wollenberger, Ulla and Scheller, Frieder W.},
title = {Electrochemical MIP-Sensors for Drugs},
series = {Current Medicinal Chemistry},
volume = {25},
journal = {Current Medicinal Chemistry},
number = {33},
publisher = {Bentham Science Publishers LTD},
address = {Sharjah},
issn = {0929-8673},
doi = {10.2174/0929867324666171005103712},
pages = {4007 -- 4019},
year = {2018},
abstract = {In order to replace bio-macromolecules by stable synthetic materials in separation techniques and bioanalysis biomimetic receptors and catalysts have been developed: Functional monomers are polymerized together with the target analyte and after template removal cavities are formed in the "molecularly imprinted polymer" (MIP) which resemble the active sites of antibodies and enzymes. Starting almost 80 years ago, around 1,100 papers on MIPs were published in 2016. Electropolymerization allows to deposit MIPs directly on voltammetric electrodes or chips for quartz crystal microbalance (QCM) and surface plasmon resonance (SPR). For the readout of MIPs for drugs amperometry, differential pulse voltammetry (DPV) and impedance spectroscopy (EIS) offer higher sensitivity as compared with QCM or SPR. Application of simple electrochemical devices allows both the reproducible preparation of MIP sensors, but also the sensitive signal generation. Electrochemical MIP-sensors for the whole arsenal of drugs, e.g. the most frequently used analgesics, antibiotics and anticancer drugs have been presented in literature and tested under laboratory conditions. These biomimetic sensors typically have measuring ranges covering the lower nano-up to millimolar concentration range and they are stable under extreme pH and in organic solvents like nonaqueous extracts.},
language = {en}
}
@article{Yarman2018,
author = {Yarman, Aysu},
title = {Electrosynthesized Molecularly Imprinted Polymer for Laccase Using the Inactivated Enzyme as the Target},
series = {Bulletin of the Korean chemical society},
volume = {39},
journal = {Bulletin of the Korean chemical society},
number = {4},
publisher = {Wiley-VCH},
address = {Weinheim},
issn = {1229-5949},
doi = {10.1002/bkcs.11413},
pages = {483 -- 488},
year = {2018},
abstract = {The first molecularly imprinted polymer (MIP) for the recognition of the copper-enzyme laccase was successfully prepared by electropolymerizing scopoletin in the presence of alkaline-inactivated enzyme. Laccase-MIP and the control polymer without laccase (nonimprinted polymer, NIP) were characterized by voltammetry using the redox marker ferricyanide. After electropolymerization, the signals for ferricyanide for both the MIP and the NIP were almost completely suppressed and increased after removal of the target from the polymer layer. Rebinding of both inactivated and active laccase decreased the ferricyanide peak currents to almost equal extent. The relative decrease of signal suppression approached saturation above 10 nM. Furthermore, the surface activity of rebound laccase toward the oxidation of catechol was investigated. The surface activity approached saturation above 10 nM, a value close to the value of the measurements with ferricyanide. Interaction of NIP with laccase brought about a six times smaller signal of catechol oxidation.},
language = {en}
}
@article{JetzschmannYarmanRustametal.2018,
author = {Jetzschmann, Katharina J. and Yarman, Aysu and Rustam, L. and Kielb, P. and Urlacher, V. B. and Fischer, A. and Weidinger, I. M. and Wollenberger, Ulla and Scheller, Frieder W.},
title = {Molecular LEGO by domain-imprinting of cytochrome P450 BM3},
series = {Colloids and surfaces : an international journal devoted to fundamental and applied research on colloid and interfacial phenomena in relation to systems of biological origin ; B, Biointerfaces},
volume = {164},
journal = {Colloids and surfaces : an international journal devoted to fundamental and applied research on colloid and interfacial phenomena in relation to systems of biological origin ; B, Biointerfaces},
publisher = {Elsevier},
address = {Amsterdam},
issn = {0927-7765},
doi = {10.1016/j.colsurfb.2018.01.047},
pages = {240 -- 246},
year = {2018},
abstract = {Hypothesis: Electrosynthesis of the MIP nano-film after binding of the separated domains or holocytochrome BM3 via an engineered anchor should result in domain-specific cavities in the polymer layer. Experiments: Both the two domains and the holo P450 BM3 have been bound prior polymer deposition via a N-terminal engineered his6-anchor to the electrode surface. Each step of MIP preparation was characterized by cyclic voltammetry of the redox-marker ferricyanide. Rebinding after template removal was evaluated by quantifying the suppression of the diffusive permeability of the signal for ferricyanide and by the NADH-dependent reduction of cytochrome c by the reductase domain (BMR). Findings: The working hypothesis is verified by the discrimination of the two domains by the respective MIPs: The holoenzyme P450 BM3 was ca. 5.5 times more effectively recognized by the film imprinted with the oxidase domain (BMO) as compared to the BMR-MIP or the non-imprinted polymer (NIP). Obviously, a cavity is formed during the imprinting process around the hiss-tag-anchored BMR which cannot accommodate the broader BMO or the P450 BM3. The affinity of the MIP towards P450 BM3 is comparable with that to the monomer in solution. The hiss-tagged P450 BM3 binds (30 percent) stronger which shows the additive effect of the interaction with the MIP and the binding to the electrode.},
language = {en}
}
@article{ZhangYarmanErdossyetal.2018,
author = {Zhang, Xiaorong and Yarman, Aysu and Erdossy, Julia and Katz, Sagie and Zebger, Ingo and Jetzschmann, Katharina J. and Altintas, Zeynep and Wollenberger, Ulla and Gyurcsanyi, Robert E. and Scheller, Frieder W.},
title = {Electrosynthesized MIPs for transferrin},
series = {Biosensors and bioelectronics : the principal international journal devoted to research, design development and application of biosensors and bioelectronics},
volume = {105},
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.2018.01.011},
pages = {29 -- 35},
year = {2018},
abstract = {Molecularly imprinted polymer (MP) nanofilrns for transferrin (Trf) have been synthesized on gold surfaces by electro-polymerizing the functional monomer scopoletin in the presence of the protein target or around pre-adsorbed Trf. As determined by atomic force microscopy (AFM) the film thickness was comparable with the molecular dimension of the target. The target (re)binding properties of the electro-synthesized MIP films was evaluated by cyclic voltammetry (CV) and square wave voltammetry (SWV) through the target-binding induced permeability changes of the MIP nanofilms to the ferricyanide redox marker, as well as by surface plasmon resonance (SPR) and surface enhanced infrared absorption spectroscopy (SEIRAS) of the immobilized protein molecules. For Trf a linear concentration dependence in the lower micromolar range and an imprinting factor of similar to 5 was obtained by SWV and SPR. Furthermore, non-target proteins including the iron-free apo-Trf were discriminated by pronounced size and shape specificity. Whilst it is generally assumed that the rebinding of the target or of cross-reacting proteins exclusively takes place at the polymer here we considered also the interaction of the protein molecules with the underlying gold transducers. We demonstrate by SWV that adsorption of proteins suppresses the signal of the redox marker even at the bare gold surface and by SEIRAS that the treatment of the MIP with proteinase K or NaOH only partially removes the target protein. Therefore, we conclude that when interpreting binding of proteins to directly MIP-covered gold electrodes the interactions between the protein and the gold surface should also be considered.},
language = {en}
}
@misc{OzcelikayKurbanogluZhangetal.2019,
author = {Ozcelikay, Goksu and Kurbanoglu, Sevinc and Zhang, Xiaorong and S{\"o}z, {\c{C}}ağla Kosak and Wollenberger, Ulla and Ozkan, Sibel A. and Yarman, Aysu and Scheller, Frieder W.},
title = {Electrochemical MIP Sensor for Butyrylcholinesterase},
series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
number = {1138},
issn = {1866-8372},
doi = {10.25932/publishup-50185},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-501854},
pages = {13},
year = {2019},
abstract = {Molecularly imprinted polymers (MIPs) mimic the binding sites of antibodies by substituting the amino acid-scaffold of proteins by synthetic polymers. In this work, the first MIP for the recognition of the diagnostically relevant enzyme butyrylcholinesterase (BuChE) is presented. The MIP was prepared using electropolymerization of the functional monomer o-phenylenediamine and was deposited as a thin film on a glassy carbon electrode by oxidative potentiodynamic polymerization. Rebinding and removal of the template were detected by cyclic voltammetry using ferricyanide as a redox marker. Furthermore, the enzymatic activity of BuChE rebound to the MIP was measured via the anodic oxidation of thiocholine, the reaction product of butyrylthiocholine. The response was linear between 50 pM and 2 nM concentrations of BuChE with a detection limit of 14.7 pM. In addition to the high sensitivity for BuChE, the sensor responded towards pseudo-irreversible inhibitors in the lower mM range.},
language = {en}
}
@misc{SchellerZhangYarmanetal.2019,
author = {Scheller, Frieder W. and Zhang, Xiaorong and Yarman, Aysu and Wollenberger, Ulla and Gyurcs{\´a}nyi, R{\´o}bert E.},
title = {Molecularly imprinted polymer-based electrochemical sensors for biopolymers},
series = {Current opinion in electrochemistry},
volume = {14},
journal = {Current opinion in electrochemistry},
publisher = {Elsevier},
address = {Amsterdam},
issn = {2451-9103},
doi = {10.1016/j.coelec.2018.12.005},
pages = {53 -- 59},
year = {2019},
abstract = {Electrochemical synthesis and signal generation dominate among the almost 1200 articles published annually on protein-imprinted polymers. Such polymers can be easily prepared directly on the electrode surface, and the polymer thickness can be precisely adjusted to the size of the target to enable its free exchange. In this architecture, the molecularly imprinted polymer (MIP) layer represents only one 'separation plate'; thus, the selectivity does not reach the values of 'bulk' measurements. The binding of target proteins can be detected straightforwardly by their modulating effect on the diffusional permeability of a redox marker through the thin MIP films. However, this generates an 'overall apparent' signal, which may include nonspecific interactions in the polymer layer and at the electrode surface. Certain targets, such as enzymes or redox active proteins, enables a more specific direct quantification of their binding to MIPs by in situ determination of the enzyme activity or direct electron transfer, respectively.},
language = {en}
}
@misc{YarmanJetzschmannNeumannetal.2017,
author = {Yarman, Aysu and Jetzschmann, Katharina J. and Neumann, Bettina and Zhang, Xiaorong and Wollenberger, Ulla and Cordin, Aude and Haupt, Karsten and Scheller, Frieder W.},
title = {Enzymes as tools in MIP-sensors},
series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
number = {1098},
issn = {1866-8372},
doi = {10.25932/publishup-47464},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-474642},
pages = {18},
year = {2017},
abstract = {Molecularly imprinted polymers (MIPs) have the potential to complement antibodies in bioanalysis, are more stable under harsh conditions, and are potentially cheaper to produce. However, the affinity and especially the selectivity of MIPs are in general lower than those of their biological pendants. Enzymes are useful tools for the preparation of MIPs for both low and high-molecular weight targets: As a green alternative to the well-established methods of chemical polymerization, enzyme-initiated polymerization has been introduced and the removal of protein templates by proteases has been successfully applied. Furthermore, MIPs have been coupled with enzymes in order to enhance the analytical performance of biomimetic sensors: Enzymes have been used in MIP-sensors as tracers for the generation and amplification of the measuring signal. In addition, enzymatic pretreatment of an analyte can extend the analyte spectrum and eliminate interferences.},
language = {en}
}
@misc{YarmanScheller2014,
author = {Yarman, Aysu and Scheller, Frieder W.},
title = {The first electrochemical MIP sensor for tamoxifen},
series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
number = {1046},
issn = {1866-8372},
doi = {10.25932/publishup-47617},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-476173},
pages = {10},
year = {2014},
abstract = {We present an electrochemical MIP sensor for tamoxifen (TAM)-a nonsteroidal anti-estrogen-which is based on the electropolymerisation of an O-phenylenediamine. resorcinol mixture directly on the electrode surface in the presence of the template molecule. Up to now only. bulk. MIPs for TAM have been described in literature, which are applied for separation in chromatography columns. Electro-polymerisation of the monomers in the presence of TAM generated a film which completely suppressed the reduction of ferricyanide. Removal of the template gave a markedly increased ferricyanide signal, which was again suppressed after rebinding as expected for filling of the cavities by target binding. The decrease of the ferricyanide peak of the MIP electrode depended linearly on the TAM concentration between 1 and 100 nM. The TAM-imprinted electrode showed a 2.3 times higher recognition of the template molecule itself as compared to its metabolite 4-hydroxytamoxifen and no cross-reactivity with the anticancer drug doxorubucin was found. Measurements at + 1.1 V caused a fouling of the electrode surface, whilst pretreatment of TAM with peroxide in presence of HRP generated an oxidation product which was reducible at 0 mV, thus circumventing the polymer formation and electrochemical interferences.},
language = {en}
}
@article{OzcelikayKurbanogluZhangetal.2019,
author = {Ozcelikay, Goksu and Kurbanoglu, Sevinc and Zhang, Xiaorong and S{\"o}z, {\c{C}}ağla Kosak and Wollenberger, Ulla and Ozkan, Sibel A. and Yarman, Aysu and Scheller, Frieder W.},
title = {Electrochemical MIP Sensor for Butyrylcholinesterase},
series = {Polymers},
volume = {11},
journal = {Polymers},
number = {12},
publisher = {MDPI},
address = {Basel},
issn = {2073-4360},
doi = {10.3390/polym11121970},
pages = {11},
year = {2019},
abstract = {Molecularly imprinted polymers (MIPs) mimic the binding sites of antibodies by substituting the amino acid-scaffold of proteins by synthetic polymers. In this work, the first MIP for the recognition of the diagnostically relevant enzyme butyrylcholinesterase (BuChE) is presented. The MIP was prepared using electropolymerization of the functional monomer o-phenylenediamine and was deposited as a thin film on a glassy carbon electrode by oxidative potentiodynamic polymerization. Rebinding and removal of the template were detected by cyclic voltammetry using ferricyanide as a redox marker. Furthermore, the enzymatic activity of BuChE rebound to the MIP was measured via the anodic oxidation of thiocholine, the reaction product of butyrylthiocholine. The response was linear between 50 pM and 2 nM concentrations of BuChE with a detection limit of 14.7 pM. In addition to the high sensitivity for BuChE, the sensor responded towards pseudo-irreversible inhibitors in the lower mM range.},
language = {en}
}
@misc{YarmanScheller2020,
author = {Yarman, Aysu and Scheller, Frieder W.},
title = {How reliable is the electrochemical readout of MIP-sensors?},
series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe},
journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe},
number = {960},
issn = {1866-8372},
doi = {10.25932/publishup-47160},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-471608},
pages = {25},
year = {2020},
abstract = {Electrochemical methods offer the simple characterization of the synthesis of molecularly imprinted polymers (MIPs) and the readouts of target binding. The binding of electroinactive analytes can be detected indirectly by their modulating effect on the diffusional permeability of a redox marker through thin MIP films. However, this process generates an overall signal, which may include nonspecific interactions with the nonimprinted surface and adsorption at the electrode surface in addition to (specific) binding to the cavities. Redox-active low-molecular-weight targets and metalloproteins enable a more specific direct quantification of their binding to MIPs by measuring the faradaic current. The in situ characterization of enzymes, MIP-based mimics of redox enzymes or enzyme-labeled targets, is based on the indication of an electroactive product. This approach allows the determination of both the activity of the bio(mimetic) catalyst and of the substrate concentration.},
language = {en}
}
@article{PengYarmanJetzschmannetal.2016,
author = {Peng, Lei and Yarman, Aysu and Jetzschmann, Katharina J. and Jeoung, Jae-Hun and Schad, Daniel and Dobbek, Holger and Wollenberger, Ursula and Scheller, Frieder W.},
title = {Molecularly Imprinted Electropolymer for a Hexameric Heme Protein with Direct Electron Transfer and Peroxide Electrocatalysis},
series = {SENSORS},
volume = {16},
journal = {SENSORS},
publisher = {MDPI},
address = {Basel},
issn = {1424-8220},
doi = {10.3390/s16030272},
pages = {1343 -- 1364},
year = {2016},
abstract = {For the first time a molecularly imprinted polymer (MIP) with direct electron transfer (DET) and bioelectrocatalytic activity of the target protein is presented. Thin films of MIPs for the recognition of a hexameric tyrosine-coordinated heme protein (HTHP) have been prepared by electropolymerization of scopoletin after oriented assembly of HTHP on a self-assembled monolayer (SAM) of mercaptoundecanoic acid (MUA) on gold electrodes. Cavities which should resemble the shape and size of HTHP were formed by template removal. Rebinding of the target protein sums up the recognition by non-covalent interactions between the protein and the MIP with the electrostatic attraction of the protein by the SAM. HTHP bound to the MIP exhibits quasi-reversible DET which is reflected by a pair of well pronounced redox peaks in the cyclic voltammograms (CVs) with a formal potential of -184.4 +/- 13.7 mV vs. Ag/AgCl (1 M KCl) at pH 8.0 and it was able to catalyze the cathodic reduction of peroxide. At saturation the MIP films show a 12-fold higher electroactive surface concentration of HTHP than the non-imprinted polymer (NIP).},
language = {en}
}
@misc{ErdossyHorvathYarmanetal.2016,
author = {Erdossy, Julia and Horvath, Viola and Yarman, Aysu and Scheller, Frieder W. and Gyurcsanyi, Robert E.},
title = {Electrosynthesized molecularly imprinted polymers for protein recognition},
series = {Trends in Analytical Chemistry},
volume = {79},
journal = {Trends in Analytical Chemistry},
publisher = {Elsevier},
address = {Oxford},
issn = {0165-9936},
doi = {10.1016/j.trac.2015.12.018},
pages = {179 -- 190},
year = {2016},
abstract = {Molecularly imprinted polymers (MIPs) for the recognition of proteins are expected to possess high affinity through the establishment of multiple interactions between the polymer matrix and the large number of functional groups of the target. However, while highly affine recognition sites need building blocks rich in complementary functionalities to their target, such units are likely to generate high levels of nonspecific binding. This paradox, that nature solved by evolution for biological receptors, needs to be addressed by the implementation of new concepts in molecular imprinting of proteins. Additionally, the structural variability, large size and incompatibility with a range of monomers made the development of protein MIPs to take a slow start. While the majority of MIP preparation methods are variants of chemical polymerization, the polymerization of electroactive functional monomers emerged as a particularly advantageous approach for chemical sensing application. Electropolymerization can be performed from aqueous solutions to preserve the natural conformation of the protein templates, with high spatial resolution and electrochemical control of the polymerization process. This review compiles the latest results, identifying major trends and providing an outlook on the perspectives of electrosynthesised protein-imprinted MIPs for chemical sensing. (C) 2016 Elsevier B.V. All rights reserved.},
language = {en}
}
@misc{MengerYarmanErdoessyetal.2016,
author = {Menger, Marcus and Yarman, Aysu and Erd{\"o}ssy, J{\´u}lia and Yildiz, Huseyin Bekir and Gyurcs{\´a}nyi, R{\´o}bert E. and Scheller, Frieder W.},
title = {MIPs and Aptamers for Recognition of Proteins in Biomimetic Sensing},
series = {Biosensors : open access journal},
volume = {6},
journal = {Biosensors : open access journal},
publisher = {MDPI},
address = {Basel},
issn = {2079-6374},
doi = {10.3390/bios6030035},
pages = {4399 -- 4413},
year = {2016},
abstract = {Biomimetic binders and catalysts have been generated in order to substitute the biological pendants in separation techniques and bioanalysis. The two major approaches use either "evolution in the test tube" of nucleotides for the preparation of aptamers or total chemical synthesis for molecularly imprinted polymers (MIPs). The reproducible production of aptamers is a clear advantage, whilst the preparation of MIPs typically leads to a population of polymers with different binding sites. The realization of binding sites in the total bulk of the MIPs results in a higher binding capacity, however, on the expense of the accessibility and exchange rate. Furthermore, the readout of the bound analyte is easier for aptamers since the integration of signal generating labels is well established. On the other hand, the overall negative charge of the nucleotides makes aptamers prone to non-specific adsorption of positively charged constituents of the sample and the "biological" degradation of non-modified aptamers and ionic strength-dependent changes of conformation may be challenging in some application.},
language = {en}
}
@article{YarmanScheller2016,
author = {Yarman, Aysu and Scheller, Frieder W.},
title = {MIP-esterase/Tyrosinase Combinations for Paracetamol and Phenacetin},
series = {Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis},
volume = {28},
journal = {Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis},
publisher = {Wiley-VCH},
address = {Weinheim},
issn = {1040-0397},
doi = {10.1002/elan.201600042},
pages = {2222 -- 2227},
year = {2016},
abstract = {A new electrochemical MIP sensor for the most frequently used drug paracetamol (PAR) was prepared by electropolymerization of mixtures containing the template molecule and the functional monomers ophenylenediamine, resorcinol and aniline. The imprinting factor of 12 reflects the effective target binding to the MIP as compared with the non-imprinted electropolymer. Combination of the MIP with a nonspecific esterase allows the measurement of phenacetin - another analgesic drug. In the second approach the PAR containing sample solution was pretreated with tyrosinase in order to prevent electrochemical interferences by ascorbic acid and uric acid. Interference-free indication at a very low electrode potential without fouling of the electrode surface was achieved with the o-phenylenediamine: resorcinol-based MIP.},
language = {en}
}
@article{SchellerYarman2015,
author = {Scheller, Frieder W. and Yarman, Aysu},
title = {Bio vs. Mimetika in der Bioanalytik},
series = {Biochemie und analytische Biochemie},
volume = {4},
journal = {Biochemie und analytische Biochemie},
number = {2},
issn = {2161-1009},
pages = {2},
year = {2015},
abstract = {Nat{\"u}rliche Evolution hat geschaffenBiopolymereauf der Basis von Aminos{\"a}uren undNukleotidezeigt hohe chemische Selektivit{\"a}t und katalytische Kraft. Die molekulare Erkennung durch Antik{\"o}rper und die katalytische Umwandlung der Substratmolek{\"u}le durch Enzyme findet in sogenannten Paratopen oder katalytischen Zentren des Makromolek{\"u}ls statt, die typischerweise 10-15 Aminos{\"a}uren umfassen. Die konzertierte Wechselwirkung zwischen den Reaktionspartnern f{\"u}hrt zu Affinit{\"a}ten bis zu nanomolaren Konzentrationen f{\"u}r die Antigenbindung und n{\"a}hert sich einer Million Ums{\"a}tze pro Sekunde anEnzym-katalysierte Reaktionen.},
language = {de}
}
@misc{PengYarmanJetzschmannetal.2017,
author = {Peng, Lei and Yarman, Aysu and Jetzschmann, Katharina J. and Jeoung, Jae-Hun and Schad, Daniel and Dobbek, Holger and Wollenberger, Ursula and Scheller, Frieder W.},
title = {Molecularly imprinted electropolymer for a hexameric heme protein with direct electron transfer and peroxide electrocatalysis},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-400627},
pages = {11},
year = {2017},
abstract = {For the first time a molecularly imprinted polymer (MIP) with direct electron transfer (DET) and bioelectrocatalytic activity of the target protein is presented. Thin films of MIPs for the recognition of a hexameric tyrosine-coordinated heme protein (HTHP) have been prepared by electropolymerization of scopoletin after oriented assembly of HTHP on a self-assembled monolayer (SAM) of mercaptoundecanoic acid (MUA) on gold electrodes. Cavities which should resemble the shape and size of HTHP were formed by template removal. Rebinding of the target protein sums up the recognition by non-covalent interactions between the protein and the MIP with the electrostatic attraction of the protein by the SAM. HTHP bound to the MIP exhibits quasi-reversible DET which is reflected by a pair of well pronounced redox peaks in the cyclic voltammograms (CVs) with a formal potential of -184.4 ± 13.7 mV vs. Ag/AgCl (1 M KCl) at pH 8.0 and it was able to catalyze the cathodic reduction of peroxide. At saturation the MIP films show a 12-fold higher electroactive surface concentration of HTHP than the non-imprinted polymer (NIP).},
language = {en}
}
@misc{MengerYarmanErdőssyetal.2017,
author = {Menger, Marcus and Yarman, Aysu and Erdőssy, J{\´u}lia and Yildiz, Huseyin Bekir and Gyurcs{\´a}nyi, R{\´o}bert E. and Scheller, Frieder W.},
title = {MIPs and aptamers for recognition of proteins in biomimetic sensing},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-400496},
pages = {19},
year = {2017},
abstract = {Biomimetic binders and catalysts have been generated in order to substitute the biological pendants in separation techniques and bioanalysis. The two major approaches use either "evolution in the test tube" of nucleotides for the preparation of aptamers or total chemical synthesis for molecularly imprinted polymers (MIPs). The reproducible production of aptamers is a clear advantage, whilst the preparation of MIPs typically leads to a population of polymers with different binding sites. The realization of binding sites in the total bulk of the MIPs results in a higher binding capacity, however, on the expense of the accessibility and exchange rate. Furthermore, the readout of the bound analyte is easier for aptamers since the integration of signal generating labels is well established. On the other hand, the overall negative charge of the nucleotides makes aptamers prone to non-specific adsorption of positively charged constituents of the sample and the "biological" degradation of non-modified aptamers and ionic strength-dependent changes of conformation may be challenging in some application.},
language = {en}
}
@misc{YarmanDechtriratBosserdtetal.2015,
author = {Yarman, Aysu and Dechtrirat, Decha and Bosserdt, Maria and Jetzschmann, Katharina J. and Gajovic-Eichelmann, Nenad and Scheller, Frieder W.},
title = {Cytochrome c-derived hybrid systems based on moleculary imprinted polymers},
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 = {3},
publisher = {Wiley-VCH},
address = {Weinheim},
issn = {1040-0397},
doi = {10.1002/elan.201400592},
pages = {573 -- 586},
year = {2015},
abstract = {Hybrid architectures which combine a MIP with an immobilized affinity ligand or a biocatalyst sum up the advantages of both components. In this paper, hybrid architectures combining a layer of a molecularly imprinted electropolymer with a mini-enzyme or a self-assembled monolayer will be presented. (i) Microperoxidase-11 (MP-11) catalyzed oxidation of the drug aminopyrine on a product-imprinted sublayer: The peroxide dependent conversion of the analyte aminopyrine takes place in the MP-11 containing layer on top of a product-imprinted electropolymer on the indicator electrode. The hierarchical architecture resulted in the elimination of interfering signals for ascorbic acid and uric acid. An advantage of the new hierarchical structure is the separation of MIP formation by electropolymerization and immobilization of the catalyst. In this way it was for the first time possible to integrate an enzyme with a MIP layer in a sensor configuration. This combination has the potential to be transferred to other enzymes, e.g. P450, opening the way to clinically important analytes. (ii) Epitope-imprinted poly-scopoletin layer for binding of the C-terminal peptide and cytochrome c (Cyt c): The MIP binds both the target peptide and the parent protein almost eight times stronger than the non-imprinted polymer with affinities in the lower micromolar range. Exchange of only one amino acid in the peptide decreases the binding by a factor of five. (iii) MUA-poly-scopoletin MIP for cytochrome c: Cyt c bound to the MIP covered gold electrode exhibits direct electron transfer with a redox potential and rate constant typical for the native protein. The MIP cover layer suppresses the displacement of the target protein by BSA or myoglobin. The combination of protein imprinted polymers with an efficient electron transfer is a new concept for characterizing electroactive proteins such as Cyt c. The competition with other proteins shows that the MIP binds its target Cyt c preferentially and that molecular shape and the charge of protein determine the binding of interfering proteins.},
language = {en}
}
@article{PengUteschYarmanetal.2015,
author = {Peng, Lei and Utesch, Tillmann and Yarman, Aysu and Jeoung, Jae-Hun and Steinborn, Silke and Dobbek, Holger and Mroginski, Maria Andrea and Tanne, Johannes and Wollenberger, Ursula and Scheller, Frieder W.},
title = {Surface-Tuned Electron Transfer and Electrocatalysis of Hexameric Tyrosine-Coordinated Heme Protein},
series = {Chemistry - a European journal},
volume = {21},
journal = {Chemistry - a European journal},
number = {20},
publisher = {Wiley-VCH},
address = {Weinheim},
issn = {0947-6539},
doi = {10.1002/chem.201405932},
pages = {7596 -- 7602},
year = {2015},
abstract = {Molecular modeling, electrochemical methods, and quartz crystal microbalance were used to characterize immobilized hexameric tyrosine-coordinated heme protein (HTHP) on bare carbon or on gold electrodes modified with positively and negatively charged self-assembled monolayers (SAMs), respectively. HTHP binds to the positively charged surface but no direct electron transfer (DET) is found due to the long distance of the active sites from the electrode surfaces. At carboxyl-terminated surfaces, the neutrally charged bottom of HTHP can bind to the SAM. For this "disc" orientation all six hemes are close to the electrode and their direct electron transfer should be efficient. HTHP on all negatively charged SAMs showed a quasi-reversible redox behavior with rate constant k(s) values between 0.93 and 2.86 s(-1) and apparent formal potentials E-app(0)' between -131.1 and -249.1 mV. On the MUA/MU-modified electrode, the maximum surface concentration corresponds to a complete monolayer of the hexameric HTHP in the disc orientation. HTHP electrostatically immobilized on negatively charged SAMs shows electrocatalysis of peroxide reduction and enzymatic oxidation of NADH.},
language = {en}
}
@article{JetzschmannJagerszkiDechtriratetal.2015,
author = {Jetzschmann, Katharina J. and Jagerszki, Gyula and Dechtrirat, Decha and Yarman, Aysu and Gajovic-Eichelmann, Nenad and Gilsing, Hans-Detlev and Schulz, Burkhard and Gyurcsanyi, Robert E. and Scheller, Frieder W.},
title = {Vectorially Imprinted Hybrid Nanofilm for Acetylcholinesterase Recognition},
series = {Advanced functional materials},
volume = {25},
journal = {Advanced functional materials},
number = {32},
publisher = {Wiley-VCH},
address = {Weinheim},
issn = {1616-301X},
doi = {10.1002/adfm.201501900},
pages = {5178 -- 5183},
year = {2015},
abstract = {Effective recognition of enzymatically active tetrameric acetylcholinesterase (AChE) is accomplished by a hybrid nanofilm composed of a propidium-terminated self-assembled monolayer (Prop-SAM) which binds AChE via its peripheral anionic site (PAS) and an ultrathin electrosynthesized molecularly imprinted polymer (MIP) cover layer of a novel carboxylate-modified derivative of 3,4-propylenedioxythiophene. The rebinding of the AChE to the MIP/Prop-SAM nanofilm covered electrode is detected by measuring in situ the enzymatic activity. The oxidative current of the released thiocholine is dependent on the AChE concentration from approximate to 0.04 x 10(-6) to 0.4 x 10(-6)m. An imprinting factor of 9.9 is obtained for the hybrid MIP, which is among the best values reported for protein imprinting. The dissociation constant characterizing the strength of the MIP-AChE binding is 4.2 x 10(-7)m indicating the dominant role of the PAS-Prop-SAM interaction, while the benefit of the MIP nanofilm covering the Prop-SAM layer is the effective suppression of the cross-reactivity toward competing proteins as compared with the Prop-SAM. The threefold selectivity gain provided by i) the shape-specific MIP filter, ii) the propidium-SAM, iii) signal generation only by the AChE bound to the nanofilm shows promise for assessing AChE activity levels in cerebrospinal fluid.},
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{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{NeumannYarmanWollenbergeretal.2014,
author = {Neumann, Bettina and Yarman, Aysu and Wollenberger, Ursula and Scheller, Frieder W.},
title = {Characterization of the enhanced peroxidatic activity of amyloid beta peptide-hemin complexes towards neurotransmitters},
series = {Analytical \& bioanalytical chemistry},
volume = {406},
journal = {Analytical \& bioanalytical chemistry},
number = {14},
publisher = {Springer},
address = {Heidelberg},
issn = {1618-2642},
doi = {10.1007/s00216-014-7822-8},
pages = {3359 -- 3364},
year = {2014},
abstract = {Binding of heme to the amyloid peptides A beta 40/42 is thought to be an initial step in the development of symptoms in the early stages of Alzheimer's disease by enhancing the intrinsic peroxidatic activity of heme. We found considerably higher acceleration of the reaction for the physiologically relevant neurotransmitters dopamine and serotonin than reported earlier for the artificial substrate 3,3',5,5'-tetramethylbenzidine (TMB). Thus, the binding of hemin to A beta peptides might play an even more crucial role in the early stages of Alzheimer's disease than deduced from these earlier results. To mimic complex formation, a new surface architecture has been developed: The interaction between the truncated amyloid peptide A beta 1-16 and hemin immobilized on an aminohexanethiol spacer on a gold electrode has been analyzed by cyclic voltammetry. The resulting complex has a redox pair with a 25 mV more cathodic formal potential than hemin alone.},
language = {en}
}
@article{YarmanScheller2014,
author = {Yarman, Aysu and Scheller, Frieder W.},
title = {The first electrochemical MIP sensor for tamoxifen},
series = {Sensors},
volume = {14},
journal = {Sensors},
number = {5},
publisher = {MDPI},
address = {Basel},
issn = {1424-8220},
doi = {10.3390/s140507647},
pages = {7647 -- 7654},
year = {2014},
abstract = {We present an electrochemical MIP sensor for tamoxifen (TAM)-a nonsteroidal anti-estrogen-which is based on the electropolymerisation of an O-phenylenediamine. resorcinol mixture directly on the electrode surface in the presence of the template molecule. Up to now only. bulk. MIPs for TAM have been described in literature, which are applied for separation in chromatography columns. Electro-polymerisation of the monomers in the presence of TAM generated a film which completely suppressed the reduction of ferricyanide. Removal of the template gave a markedly increased ferricyanide signal, which was again suppressed after rebinding as expected for filling of the cavities by target binding. The decrease of the ferricyanide peak of the MIP electrode depended linearly on the TAM concentration between 1 and 100 nM. The TAM-imprinted electrode showed a 2.3 times higher recognition of the template molecule itself as compared to its metabolite 4-hydroxytamoxifen and no cross-reactivity with the anticancer drug doxorubucin was found. Measurements at + 1.1 V caused a fouling of the electrode surface, whilst pretreatment of TAM with peroxide in presence of HRP generated an oxidation product which was reducible at 0 mV, thus circumventing the polymer formation and electrochemical interferences.},
language = {en}
}
@article{YarmanSchulzSygmundetal.2014,
author = {Yarman, Aysu and Schulz, Christopher and Sygmund, Cristoph and Ludwig, Roland and Gorton, Lo and Wollenberger, Ursula and Scheller, Frieder W.},
title = {Third generation ATP sensor with enzymatic analyte recycling},
series = {Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis},
volume = {26},
journal = {Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis},
number = {9},
publisher = {Wiley-VCH},
address = {Weinheim},
issn = {1040-0397},
doi = {10.1002/elan.201400231},
pages = {2043 -- 2048},
year = {2014},
abstract = {For the first time the direct electron transfer of an enzyme - cellobiose dehydrogenase, CDH - has been coupled with the hexokinase catalyzed competition for glucose in a sensor for ATP. To enhance the signal output for ATP, pyruvate kinase was coimmobilized to recycle ADP by the phosphoenolpyruvate driven reaction. The new sensor overcomes the limit of 1:1 stoichiometry of the sequential or competitive conversion of ATP by effective enzymatic recycling of the analyte. The anodic oxidation of the glucose converting CDH proceeds at electrode potentials below 0 mV vs. Ag vertical bar AgCl thus potentially interfering substances like ascorbic acid or catecholamines do not influence the measuring signal. The combination of direct electron transfer of CDH with the enzymatic recycling results in an interference-free and oxygen-independent measurement of ATP in the lower mu molar concentration range with a lower limit of detection of 63.3 nM (S/N=3).},
language = {en}
}
@article{YarmanNagelGajovicEichelmannetal.2011,
author = {Yarman, Aysu and Nagel, Thomas and Gajovic-Eichelmann, Nenad and Fischer, Anna and Wollenberger, Ursula and Scheller, Frieder W.},
title = {Bioelectrocatalysis by Microperoxidase-11 in a Multilayer Architecture of Chitosan Embedded Gold Nanoparticles},
series = {Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis},
volume = {23},
journal = {Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis},
number = {3},
publisher = {Wiley-Blackwell},
address = {Malden},
issn = {1040-0397},
doi = {10.1002/elan.201000535},
pages = {611 -- 618},
year = {2011},
abstract = {We report on the redox behaviour of the microperoxidase-11 (MP-11) which has been electrostatically immobilized in a matrix of chitosan-embedded gold nanoparticles on the surface of a glassy carbon electrode. MP-11 contains a covalently bound heme c as the redox active group that exchanges electrons with the electrode via the gold nanoparticles. Electroactive surface concentration of MP-11 at high scan rate is between 350+/-50 pmol cm(-2), which reflects a multilayer process. The formal potential (E degrees') of MP-11 in the gold nanoparticles-chitosan film was estimated to be -(267.7+/-2.9) mV at pH 7.0. The heterogeneous electron transfer rate constant (k(s)) starts at 1.21 s(-1) and levels off at 6.45 s(-1) in the scan rate range from 0.1 to 2.0 V s(-1). Oxidation and reduction of MP-11 by hydrogen peroxide and superoxide, respectively have been coupled to the direct electron transfer of MP-11.},
language = {en}
}
@article{YarmanBadalyanGajovicEichelmannetal.2011,
author = {Yarman, Aysu and Badalyan, Artavazd and Gajovic-Eichelmann, Nenad and Wollenberger, Ursula and Scheller, Frieder W.},
title = {Enzyme electrode for aromatic compounds exploiting the catalytic activities of microperoxidase-11},
series = {Biosensors and bioelectronics : the principal international journal devoted to research, design development and application of biosensors and bioelectronics},
volume = {30},
journal = {Biosensors and bioelectronics : the principal international journal devoted to research, design development and application of biosensors and bioelectronics},
number = {1},
publisher = {Elsevier},
address = {Oxford},
issn = {0956-5663},
doi = {10.1016/j.bios.2011.09.004},
pages = {320 -- 323},
year = {2011},
abstract = {Microperoxidase-11 (MR-11) which has been immobilised in a matrix of chitosan-embedded gold nanoparticles on the surface of a glassy carbon electrode catalyzes the conversion of aromatic substances. This peroxide-dependent catalysis of microperoxidase has been applied in an enzyme electrode for the first time to indicate aromatic compounds such as aniline. 4-fluoroaniline, catechol and p-aminophenol. The electrode signal is generated by the cathodic reduction of the quinone or quinoneimine which is formed in the presence of both MP-II and peroxide from the substrate. The same sensor principle will be extended to aromatic drugs.},
language = {en}
}
@article{YarmanGroebeNeumannetal.2012,
author = {Yarman, Aysu and Gr{\"o}be, Glenn and Neumann, Bettina and Kinne, Mathias and Gajovic-Eichelmann, Nenad and Wollenberger, Ursula and Hofrichter, Martin and Ullrich, Rene and Scheibner, Katrin and Scheller, Frieder W.},
title = {The aromatic peroxygenase from Marasmius rutola-a new enzyme for biosensor applications},
series = {Analytical \& bioanalytical chemistry},
volume = {402},
journal = {Analytical \& bioanalytical chemistry},
number = {1},
publisher = {Springer},
address = {Heidelberg},
issn = {1618-2642},
doi = {10.1007/s00216-011-5497-y},
pages = {405 -- 412},
year = {2012},
abstract = {The aromatic peroxygenase (APO; EC 1.11.2.1) from the agraric basidomycete Marasmius rotula (MroAPO) immobilized at the chitosan-capped gold-nanoparticle-modified glassy carbon electrode displayed a pair of redox peaks with a midpoint potential of -278.5 mV vs. AgCl/AgCl (1 M KCl) for the Fe(2+)/Fe(3+) redox couple of the heme-thiolate-containing protein. MroAPO oxidizes aromatic substrates such as aniline, p-aminophenol, hydroquinone, resorcinol, catechol, and paracetamol by means of hydrogen peroxide. The substrate spectrum overlaps with those of cytochrome P450s and plant peroxidases which are relevant in environmental analysis and drug monitoring. In M. rotula peroxygenase-based enzyme electrodes, the signal is generated by the reduction of electrode-active reaction products (e.g., p-benzoquinone and p-quinoneimine) with electro-enzymatic recycling of the analyte. In these enzyme electrodes, the signal reflects the conversion of all substrates thus representing an overall parameter in complex media. The performance of these sensors and their further development are discussed.},
language = {en}
}
@article{YarmanScheller2013,
author = {Yarman, Aysu and Scheller, Frieder W.},
title = {Coupling biocatalysis with molecular imprinting in a biomimetic sensor},
series = {Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition},
volume = {52},
journal = {Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition},
number = {44},
publisher = {Wiley-VCH},
address = {Weinheim},
issn = {1433-7851},
doi = {10.1002/anie.201305368},
pages = {11521 -- 11525},
year = {2013},
language = {en}
}
@article{YarmanWollenbergerScheller2013,
author = {Yarman, Aysu and Wollenberger, Ursula and Scheller, Frieder W.},
title = {Sensors based on cytochrome P450 and CYP mimicking systems},
series = {ELECTROCHIMICA ACTA},
volume = {110},
journal = {ELECTROCHIMICA ACTA},
publisher = {PERGAMON-ELSEVIER SCIENCE LTD},
address = {OXFORD},
issn = {0013-4686},
doi = {10.1016/j.electacta.2013.03.154},
pages = {63 -- 72},
year = {2013},
abstract = {Cytochrome P450 enzymes (CYPs) act on more than 90 percent of all drugs currently on the market. The catalytic cycle requires electron supply to the heme iron in the presence of oxygen. Electrochemistry allows to characterise the reaction mechanism of these redox enzymes by observing the electron transfer in real time. According to the number of publications on protein electrochemistry CYP has the third position after glucose oxidase and cytochrome c. CYP based enzyme electrodes for the quantification of drugs, metabolites or pesticides have been developed using different iso-enzymes. A crucial step in the sensor development is the efficiency of coupling the biocatalytic systems with the electrode is. In the 1970s the direct electron transfer of heme and heme peptides called microperoxidases (MPs) was used as model of oxidoreductases. They exhibit a broad substrate spectrum including hydroxylation of selected aromatic substrates, demethylation and epoxidation by means of hydrogen peroxide. It overlaps with that of P450 making heme and MPs to alternate recognition elements in biosensors for the detection of typical CYP substrates. In these enzyme electrodes the signal is generated by the conversion of all substrates thus representing in complex media an overall parameter. By combining the biocatalytic substrate conversion with selective binding to a molecularly imprinted polymer layer the specificity has been improved. Here we discuss different approaches of biosensors based on CYP, microperoxidases and catalytically active MIPs and discuss their potential as recognition elements in biosensors. The performance of these sensors and their further development are discussed. (C) 2013 Elsevier Ltd. All rights reserved.},
language = {en}
}
@phdthesis{Yarman2012,
author = {Yarman, Aysu},
title = {Biomimetic sensors for substrates of peroxidases and cytochrome P450s},
address = {Potsdam},
pages = {121 S.},
year = {2012},
language = {en}
}