TY - JOUR
A1 - Ozcelikay, Goksu
A1 - Kurbanoglu, Sevinc
A1 - Zhang, Xiaorong
A1 - Söz, Çağla Kosak
A1 - Wollenberger, Ulla
A1 - Ozkan, Sibel A.
A1 - Yarman, Aysu
A1 - Scheller, Frieder W.
T1 - Electrochemical MIP Sensor for Butyrylcholinesterase
JF - Polymers
N2 - 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.
KW - molecularly imprinted polymers
KW - biomimetic sensors
KW - butyrylcholinesterase
KW - o-phenylenediamine
KW - rivastigmine
Y1 - 2019
U6 - https://doi.org/10.3390/polym11121970
SN - 2073-4360
VL - 11
IS - 12
PB - MDPI
CY - Basel
ER -
TY - JOUR
A1 - Yarman, Aysu
T1 - Electrosynthesized Molecularly Imprinted Polymer for Laccase Using the Inactivated Enzyme as the Target
JF - Bulletin of the Korean chemical society
N2 - 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.
KW - Molecularly imprinted polymers
KW - Biomimetic sensors
KW - Laccase
KW - Electropolymerization
KW - Scopoletin
Y1 - 2018
U6 - https://doi.org/10.1002/bkcs.11413
SN - 1229-5949
VL - 39
IS - 4
SP - 483
EP - 488
PB - Wiley-VCH
CY - Weinheim
ER -
TY - JOUR
A1 - Yarman, Aysu
A1 - Scheller, Frieder W.
T1 - How reliable is the electrochemical readout of MIP sensors?
JF - Sensors
N2 - 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.
KW - molecularly imprinted polymers
KW - electropolymerization
KW - direct electron
KW - transfer
KW - catalysis
KW - redox marker
KW - gate effect
Y1 - 2020
U6 - https://doi.org/10.3390/s20092677
SN - 1424-8220
VL - 20
IS - 9
PB - MDPI
CY - Basel
ER -
TY - GEN
A1 - Yarman, Aysu
A1 - Jetzschmann, Katharina J.
A1 - Neumann, Bettina
A1 - Zhang, Xiaorong
A1 - Wollenberger, Ulla
A1 - Cordin, Aude
A1 - Haupt, Karsten
A1 - Scheller, Frieder W.
T1 - Enzymes as tools in MIP-sensors
T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2 - 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.
T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1098
KW - enzymatic MIP synthesis
KW - template digestion
KW - enzyme tracer
KW - enzymatic analyte conversion
KW - molecularly imprinted polymers
Y1 - 2021
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-474642
SN - 1866-8372
IS - 1098
ER -
TY - JOUR
A1 - Ozcelikay, Goksu
A1 - Kurbanoglu, Sevinc
A1 - Yarman, Aysu
A1 - Scheller, Frieder W.
A1 - Ozkan, Sibel A.
T1 - Au-Pt nanoparticles based molecularly imprinted nanosensor for electrochemical detection of the lipopeptide antibiotic drug Daptomycin
JF - Sensors and actuators : B, Chemical
N2 - 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.
KW - molecularly imprinted polymer
KW - Daptomycin
KW - platinum nanoparticles
KW - gold
KW - nanoparticles
KW - modified electrodes
Y1 - 2020
U6 - https://doi.org/10.1016/j.snb.2020.128285
SN - 0925-4005
VL - 320
PB - Elsevier Science
CY - Amsterdam
ER -
TY - GEN
A1 - Yarman, Aysu
A1 - Scheller, Frieder W.
T1 - How reliable is the electrochemical readout of MIP-sensors?
T2 - Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe
N2 - 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.
T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 960
KW - molecularly imprinted polymers
KW - electropolymerization
KW - direct electron transfer
KW - catalysis
KW - redox marker
KW - gate effect
Y1 - 2020
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-471608
SN - 1866-8372
IS - 960
ER -
TY - JOUR
A1 - Yarman, Aysu
A1 - Jetzschmann, Katharina J.
A1 - Neumann, Bettina
A1 - Zhang, Xiaorong
A1 - Wollenberger, Ulla
A1 - Cordin, Aude
A1 - Haupt, Karsten
A1 - Scheller, Frieder W.
T1 - Enzymes as Tools in MIP-Sensors
JF - Chemosensors
N2 - 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.
KW - enzymatic MIP synthesis
KW - template digestion
KW - enzyme tracer
KW - enzymatic analyte conversion
KW - molecularly imprinted polymers
Y1 - 2017
U6 - https://doi.org/10.3390/chemosensors5020011
SN - 2227-9040
VL - 5
PB - MDPI
CY - Basel
ER -
TY - JOUR
A1 - Zhang, Xiaorong
A1 - Yarman, Aysu
A1 - Erdossy, Julia
A1 - Katz, Sagie
A1 - Zebger, Ingo
A1 - Jetzschmann, Katharina J.
A1 - Altintas, Zeynep
A1 - Wollenberger, Ulla
A1 - Gyurcsanyi, Robert E.
A1 - Scheller, Frieder W.
T1 - Electrosynthesized MIPs for transferrin
BT - Plastibodies or nano-filters?
JF - Biosensors and bioelectronics : the principal international journal devoted to research, design development and application of biosensors and bioelectronics
N2 - 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.
KW - Molecularly imprinted polymer
KW - Scopoletin
KW - Transferrin
KW - Protein adsorption
KW - Redox marker
Y1 - 2018
U6 - https://doi.org/10.1016/j.bios.2018.01.011
SN - 0956-5663
SN - 1873-4235
VL - 105
SP - 29
EP - 35
PB - Elsevier
CY - Oxford
ER -
TY - JOUR
A1 - Jetzschmann, Katharina J.
A1 - Yarman, Aysu
A1 - Rustam, L.
A1 - Kielb, P.
A1 - Urlacher, V. B.
A1 - Fischer, A.
A1 - Weidinger, I. M.
A1 - Wollenberger, Ulla
A1 - Scheller, Frieder W.
T1 - Molecular LEGO by domain-imprinting of cytochrome P450 BM3
JF - 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
N2 - 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.
KW - Molecularly imprinted polymers
KW - Protein imprinting
KW - Electropolymerization
KW - Cytochrome P450
Y1 - 2018
U6 - https://doi.org/10.1016/j.colsurfb.2018.01.047
SN - 0927-7765
SN - 1873-4367
VL - 164
SP - 240
EP - 246
PB - Elsevier
CY - Amsterdam
ER -
TY - JOUR
A1 - Scheller, Frieder W.
A1 - Zhang, Xiaorong
A1 - Yarman, Aysu
A1 - Wollenberger, Ulla
A1 - Gyurcsányi, Róbert E.
T1 - Molecularly imprinted polymer-based electrochemical sensors for biopolymers
JF - Current opinion in electrochemistry
N2 - 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.
KW - Electropolymerization
KW - Direct electron transfer
KW - Redox marker
KW - Epitope imprinting
KW - Biomarker
Y1 - 2018
U6 - https://doi.org/10.1016/j.coelec.2018.12.005
SN - 2451-9103
VL - 14
SP - 53
EP - 59
PB - Elsevier
CY - Amsterdam
ER -
TY - JOUR
A1 - Yarman, Aysu
A1 - Kurbanoglu, Sevinc
A1 - Jetzschmann, Katharina J.
A1 - Ozkan, Sibel A.
A1 - Wollenberger, Ulla
A1 - Scheller, Frieder W.
T1 - Electrochemical MIP-Sensors for Drugs
JF - Current Medicinal Chemistry
N2 - 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.
KW - Biomimetic sensors
KW - molecularly imprinted polymers
KW - drug sensors
KW - drug imprinting
KW - electropolymerization
KW - electrochemical sensors
Y1 - 2018
U6 - https://doi.org/10.2174/0929867324666171005103712
SN - 0929-8673
SN - 1875-533X
VL - 25
IS - 33
SP - 4007
EP - 4019
PB - Bentham Science Publishers LTD
CY - Sharjah
ER -
TY - JOUR
A1 - Yarman, Aysu
T1 - Development of a molecularly imprinted polymer-based electrochemical sensor for tyrosinase
JF - Turkish journal of chemistry
N2 - 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.
KW - Molecularly imprinted polymers
KW - biomimetic sensors
KW - tyrosinase
KW - electropolymerization
KW - scopoletin
KW - ophenylenediamine
Y1 - 2017
U6 - https://doi.org/10.3906/kim-1708-68
SN - 1300-0527
VL - 42
IS - 2
SP - 346
EP - 354
PB - Türkiye Bilimsel ve Teknik Araştırma Kurumu
CY - Ankara
ER -
TY - JOUR
A1 - Kurbanoglu, Sevinc
A1 - Yarman, Aysu
T1 - Simultaneous determination of hydrochlorothiazide and irbesartan from pharmaceutical dosage forms with RP-HPLC
T1 - Farmasötik Dozaj Formlarında TF-YPSK ile Hidroklorotiyazid ve
İrbesartanın Eş Zamanlı Tayini
JF - Turkish journal of pharmaceutical sciences
N2 - 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.
N2 - Amaç: Bu çalışmada, irbesartan (IRBE) ve hidroklorotiyazidin (HCT) eşzamanlı tayini için basit ve hızlı bir ters fazlı yüksek performanslı sıvı
kromatografisi (TF-YPSK) yöntemi geliştirilmiş ve validasyon çalışmaları yapılmıştır.
Gereç ve Yöntemler: Deneysel koşullar; farklı tampon çözeltileri, çeşitli pH değerleri, sıcaklık, mobil fazın bileşimi, akış hızının etkisi gibi
parametrelerin üzerinden optimize edildi.
Bulgular: Bu antihipertansif ajanlar için geliştirilen TF-YPSK yönteminin tüm validasyon parametrelerine ilişkin çalışmalar yapılmış, ve IRBE 0,1-25
μg mL-1 doğrusal aralığında ve HCT 0,25-25 μg mL-1 doğrusal aralığında tespit edilmiştir. Ayrıca önerilen TF-YPSK yöntemi ile IRBE için 0,008 μg
mL-1 ve HCT için 0,012 μg mL-1 tayin alt sınır değerleri bulunmuştur. Geliştirilen yöntem, insan serumunda ve farmasötik dozaj formlarında bulunan
IRBE ve HCT’nin belirlenmesi için başarıyla uygulanmıştır.
Sonuç: Bu antihipertansif ilaçların miktar tayininde önerilen YPSK analiz yönteminin, analiz süresinin önemli olduğu ilaç firmalarında rahatlıkla
kullanılabileceği ve uygulanabileceği düşünülmektedir.
KW - HPLC
KW - irbesartan
KW - hydrochlorothiazide
KW - pharmaceutical dosage forms
Y1 - 2020
U6 - https://doi.org/10.4274/tjps.galenos.2019.76094
SN - 1304-530X
VL - 17
IS - 5
SP - 523
EP - 527
PB - Turkish Pharmacists Association
CY - Çankaya-Ankara
ER -
TY - GEN
A1 - Ozcelikay, Goksu
A1 - Kurbanoglu, Sevinc
A1 - Zhang, Xiaorong
A1 - Söz, Çağla Kosak
A1 - Wollenberger, Ulla
A1 - Ozkan, Sibel A.
A1 - Yarman, Aysu
A1 - Scheller, Frieder W.
T1 - Electrochemical MIP Sensor for Butyrylcholinesterase
T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2 - 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.
T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1138
KW - molecularly imprinted polymers
KW - biomimetic sensors
KW - butyrylcholinesterase
KW - o-phenylenediamine
KW - rivastigmine
Y1 - 2021
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-501854
SN - 1866-8372
IS - 1138
ER -
TY - GEN
A1 - Yarman, Aysu
A1 - Scheller, Frieder W.
T1 - The first electrochemical MIP sensor for tamoxifen
T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2 - 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.
T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1046
KW - molecularly imprinted polymers
KW - anticancer drug
KW - tamoxifen
KW - electropolymerisation
Y1 - 2020
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-476173
SN - 1866-8372
IS - 1046
ER -
TY - JOUR
A1 - Scheller, Frieder W.
A1 - Yarman, Aysu
A1 - Bachmann, Till
A1 - Hirsch, Thomas
A1 - Kubick, Stefan
A1 - Renneberg, Reinhard
A1 - Schumacher, Soeren
A1 - Wollenberger, Ursula
A1 - Teller, Carsten
A1 - Bier, Frank Fabian
ED - Gu, MB
ED - Kim, HS
T1 - Future of biosensors: a personal view
JF - Advances in biochemical engineering, biotechnology
JF - Advances in Biochemical Engineering-Biotechnology
N2 - 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.
KW - Biosensors
KW - Molecularly imprinted polymers
KW - Personalized medicine
Y1 - 2014
SN - 978-3-642-54143-8; 978-3-642-54142-1
U6 - https://doi.org/10.1007/10_2013_251
SN - 0724-6145
VL - 140
SP - 1
EP - 28
PB - Springer
CY - Berlin
ER -
TY - THES
A1 - Yarman, Aysu
T1 - Biomimetic sensors for substrates of peroxidases and cytochrome P450s
Y1 - 2012
CY - Potsdam
ER -
TY - JOUR
A1 - Yarman, Aysu
A1 - Scheller, Frieder W.
T1 - Coupling biocatalysis with molecular imprinting in a biomimetic sensor
JF - Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition
KW - biomimetic sensors
KW - electropolymers
KW - enzymes
KW - hierarchical structures
KW - molecularly imprinted polymers
Y1 - 2013
U6 - https://doi.org/10.1002/anie.201305368
SN - 1433-7851
SN - 1521-3773
VL - 52
IS - 44
SP - 11521
EP - 11525
PB - Wiley-VCH
CY - Weinheim
ER -
TY - JOUR
A1 - Yarman, Aysu
A1 - Wollenberger, Ursula
A1 - Scheller, Frieder W.
T1 - Sensors based on cytochrome P450 and CYP mimicking systems
JF - ELECTROCHIMICA ACTA
N2 - 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.
KW - Cytochrome P450
KW - Microperoxidases
KW - Catalytically active molecularly imprinted polymers
KW - Biosensors
KW - Personalised medicine
Y1 - 2013
U6 - https://doi.org/10.1016/j.electacta.2013.03.154
SN - 0013-4686
SN - 1873-3859
VL - 110
SP - 63
EP - 72
PB - PERGAMON-ELSEVIER SCIENCE LTD
CY - OXFORD
ER -
TY - JOUR
A1 - Yarman, Aysu
A1 - Schulz, Christopher
A1 - Sygmund, Cristoph
A1 - Ludwig, Roland
A1 - Gorton, Lo
A1 - Wollenberger, Ursula
A1 - Scheller, Frieder W.
T1 - Third generation ATP sensor with enzymatic analyte recycling
JF - Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis
N2 - 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).
KW - ATP
KW - Third generation sensor
KW - Enzymatic recycling
KW - Cellobiose dehydrogenase
KW - Hexokinase
KW - Pyruvate kinase
Y1 - 2014
U6 - https://doi.org/10.1002/elan.201400231
SN - 1040-0397
SN - 1521-4109
VL - 26
IS - 9
SP - 2043
EP - 2048
PB - Wiley-VCH
CY - Weinheim
ER -
TY - JOUR
A1 - Yarman, Aysu
A1 - Badalyan, Artavazd
A1 - Gajovic-Eichelmann, Nenad
A1 - Wollenberger, Ursula
A1 - Scheller, Frieder W.
T1 - Enzyme electrode for aromatic compounds exploiting the catalytic activities of microperoxidase-11
JF - Biosensors and bioelectronics : the principal international journal devoted to research, design development and application of biosensors and bioelectronics
N2 - 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.
KW - Microperoxidase-11
KW - Nanoparticles
KW - p-Aminophenol
KW - Aniline
KW - Catechol
KW - 4-Fluoroaniline
KW - Biosensors
Y1 - 2011
U6 - https://doi.org/10.1016/j.bios.2011.09.004
SN - 0956-5663
VL - 30
IS - 1
SP - 320
EP - 323
PB - Elsevier
CY - Oxford
ER -
TY - JOUR
A1 - Peng, Lei
A1 - Utesch, Tillmann
A1 - Yarman, Aysu
A1 - Jeoung, Jae-Hun
A1 - Steinborn, Silke
A1 - Dobbek, Holger
A1 - Mroginski, Maria Andrea
A1 - Tanne, Johannes
A1 - Wollenberger, Ursula
A1 - Scheller, Frieder W.
T1 - Surface-Tuned Electron Transfer and Electrocatalysis of Hexameric Tyrosine-Coordinated Heme Protein
JF - Chemistry - a European journal
N2 - 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.
KW - electrochemistry
KW - electron transfer
KW - heme proteins
KW - molecular modeling
KW - monolayers
Y1 - 2015
U6 - https://doi.org/10.1002/chem.201405932
SN - 0947-6539
SN - 1521-3765
VL - 21
IS - 20
SP - 7596
EP - 7602
PB - Wiley-VCH
CY - Weinheim
ER -
TY - JOUR
A1 - Jetzschmann, Katharina J.
A1 - Jagerszki, Gyula
A1 - Dechtrirat, Decha
A1 - Yarman, Aysu
A1 - Gajovic-Eichelmann, Nenad
A1 - Gilsing, Hans-Detlev
A1 - Schulz, Burkhard
A1 - Gyurcsanyi, Robert E.
A1 - Scheller, Frieder W.
T1 - Vectorially Imprinted Hybrid Nanofilm for Acetylcholinesterase Recognition
JF - Advanced functional materials
N2 - 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.
KW - acetylcholinesterase
KW - biomimetic sensors
KW - molecularly imprinted electropolymers
KW - peripheral anionic site
KW - propidium
Y1 - 2015
U6 - https://doi.org/10.1002/adfm.201501900
SN - 1616-301X
SN - 1616-3028
VL - 25
IS - 32
SP - 5178
EP - 5183
PB - Wiley-VCH
CY - Weinheim
ER -
TY - JOUR
A1 - Yarman, Aysu
A1 - Nagel, Thomas
A1 - Gajovic-Eichelmann, Nenad
A1 - Fischer, Anna
A1 - Wollenberger, Ursula
A1 - Scheller, Frieder W.
T1 - Bioelectrocatalysis by Microperoxidase-11 in a Multilayer Architecture of Chitosan Embedded Gold Nanoparticles
JF - Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis
N2 - 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.
KW - Microperoxidase
KW - Direct electron transfer
KW - Nanoparticles
KW - Hydrogen peroxide
KW - Superoxide
KW - Bioelectrocatalysis
Y1 - 2011
U6 - https://doi.org/10.1002/elan.201000535
SN - 1040-0397
VL - 23
IS - 3
SP - 611
EP - 618
PB - Wiley-Blackwell
CY - Malden
ER -
TY - JOUR
A1 - Yarman, Aysu
A1 - Scheller, Frieder W.
T1 - The first electrochemical MIP sensor for tamoxifen
JF - Sensors
N2 - 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.
KW - molecularly imprinted polymers
KW - anticancer drug
KW - tamoxifen
KW - electropolymerisation
Y1 - 2014
U6 - https://doi.org/10.3390/s140507647
SN - 1424-8220
VL - 14
IS - 5
SP - 7647
EP - 7654
PB - MDPI
CY - Basel
ER -
TY - JOUR
A1 - Neumann, Bettina
A1 - Yarman, Aysu
A1 - Wollenberger, Ursula
A1 - Scheller, Frieder W.
T1 - Characterization of the enhanced peroxidatic activity of amyloid beta peptide-hemin complexes towards neurotransmitters
JF - Analytical & bioanalytical chemistry
N2 - 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.
KW - Peroxidatic activity
Y1 - 2014
U6 - https://doi.org/10.1007/s00216-014-7822-8
SN - 1618-2642
SN - 1618-2650
VL - 406
IS - 14
SP - 3359
EP - 3364
PB - Springer
CY - Heidelberg
ER -
TY - JOUR
A1 - Yarman, Aysu
A1 - Gröbe, Glenn
A1 - Neumann, Bettina
A1 - Kinne, Mathias
A1 - Gajovic-Eichelmann, Nenad
A1 - Wollenberger, Ursula
A1 - Hofrichter, Martin
A1 - Ullrich, Rene
A1 - Scheibner, Katrin
A1 - Scheller, Frieder W.
T1 - The aromatic peroxygenase from Marasmius rutola-a new enzyme for biosensor applications
JF - Analytical & bioanalytical chemistry
N2 - 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.
KW - Unspecific peroxygenase
KW - Cytochrome P450
KW - Biosensors
KW - Phenolic substances
Y1 - 2012
U6 - https://doi.org/10.1007/s00216-011-5497-y
SN - 1618-2642
VL - 402
IS - 1
SP - 405
EP - 412
PB - Springer
CY - Heidelberg
ER -
TY - JOUR
A1 - Erdossy, Julia
A1 - Horvath, Viola
A1 - Yarman, Aysu
A1 - Scheller, Frieder W.
A1 - Gyurcsanyi, Robert E.
T1 - Electrosynthesized molecularly imprinted polymers for protein recognition
JF - Trends in Analytical Chemistry
N2 - 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.
KW - Molecularly imprinted polymers
KW - Proteins
KW - Surface imprinting
KW - Electropolymerization
KW - Nanostructuring
KW - Hybrid nanofilms
Y1 - 2016
U6 - https://doi.org/10.1016/j.trac.2015.12.018
SN - 0165-9936
SN - 1879-3142
VL - 79
SP - 179
EP - 190
PB - Elsevier
CY - Oxford
ER -
TY - JOUR
A1 - Yarman, Aysu
A1 - Scheller, Frieder W.
T1 - MIP-esterase/Tyrosinase Combinations for Paracetamol and Phenacetin
JF - Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis
N2 - 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.
KW - Paracetamol
KW - Molecularly imprinted polymers
KW - Electropolymerization
KW - Tyrosinase
KW - Esterase
KW - Phenacetin
Y1 - 2016
U6 - https://doi.org/10.1002/elan.201600042
SN - 1040-0397
SN - 1521-4109
VL - 28
SP - 2222
EP - 2227
PB - Wiley-VCH
CY - Weinheim
ER -
TY - JOUR
A1 - Yarman, Aysu
A1 - Dechtrirat, Decha
A1 - Bosserdt, Maria
A1 - Jetzschmann, Katharina J.
A1 - Gajovic-Eichelmann, Nenad
A1 - Scheller, Frieder W.
T1 - Cytochrome c-derived hybrid systems based on moleculary imprinted polymers
JF - Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis
N2 - 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.
KW - Molecularly imprinted polymers
KW - Microperoxidase-11
KW - Cytochrome c
KW - Catalytically active MIPs
KW - Epitope imprinting
KW - Monoclonal MIPs
Y1 - 2015
U6 - https://doi.org/10.1002/elan.201400592
SN - 1040-0397
SN - 1521-4109
VL - 27
IS - 3
SP - 573
EP - 586
PB - Wiley-VCH
CY - Weinheim
ER -
TY - JOUR
A1 - Scheller, Frieder W.
A1 - Yarman, Aysu
T1 - Bio vs. Mimetika in der Bioanalytik
T1 - Bio vs. Mimetics in Bioanalysis: An Editorial
BT - ein Editorial
JF - Biochemie und analytische Biochemie
N2 - Natürliche Evolution hat geschaffenBiopolymereauf der Basis von Aminosäuren undNukleotidezeigt hohe chemische Selektivität und katalytische Kraft. Die molekulare Erkennung durch Antikörper und die katalytische Umwandlung der Substratmoleküle durch Enzyme findet in sogenannten Paratopen oder katalytischen Zentren des Makromoleküls statt, die typischerweise 10-15 Aminosäuren umfassen. Die konzertierte Wechselwirkung zwischen den Reaktionspartnern führt zu Affinitäten bis zu nanomolaren Konzentrationen für die Antigenbindung und nähert sich einer Million Umsätze pro Sekunde anEnzym-katalysierte Reaktionen.
N2 - Natural evolution has created biopolymers on the basis of amino
acids and nucleotides showing high chemical selectivity and catalytic
power. Molecular recognition by antibodies and catalytic conversion
of the substrate molecules by enzymes take place in so called paratopes or catalytic centres of the macromolecule which comprise typically 10-15 amino acids. The concerted interaction between the reaction partners result in affinities down to nanomolar concentrations for the antigen binding and approaches one million turnovers per second in enzyme-catalyzed reactions.
Nucleic acids bind complimentary single stranded nucleic acids by
base pairing (hybridisation) with nanomolar affinities but also interact highly specific with proteins, e.g. transcription factors, and lowmolecular weight molecules and even with ions.
Biomimetic binders and catalysts have been generated using
“evolution in the test tube” of non-natural nucleotides or total
chemical synthesis of (molecularly imprinted) polymers in order to
substitute the biological pendants in bioanalysis.
Y1 - 2015
SN - 2161-1009
VL - 4
IS - 2
ER -
TY - JOUR
A1 - Bognár, Zsófia
A1 - Supala, Eszter
A1 - Yarman, Aysu
A1 - Zhang, Xiaorong
A1 - Bier, Frank Fabian
A1 - Scheller, Frieder W.
A1 - Gyurcsanyi, Róbert E.
T1 - Peptide epitope-imprinted polymer microarrays for selective protein recognition
BT - application for SARS-CoV-2 RBD protein
JF - Chemical science / RSC, Royal Society of Chemistry
N2 - 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.
Y1 - 2021
U6 - https://doi.org/10.1039/d1sc04502d
SN - 2041-6539
VL - 13
IS - 5
SP - 1263
EP - 1269
PB - Royal Society of Chemistry
CY - Cambridge
ER -
TY - JOUR
A1 - Tanne, Johannes
A1 - Jeoung, Jae-Hun
A1 - Peng, Lei
A1 - Yarman, Aysu
A1 - Dietzel, Birgit
A1 - Schulz, Burkhard
A1 - Schad, Daniel
A1 - Dobbek, Holger
A1 - Wollenberger, Ursula
A1 - Bier, Frank Fabian
A1 - Scheller, Frieder W.
T1 - Direct Electron Transfer and Bioelectrocatalysis by a Hexameric, Heme Protein at Nanostructured Electrodes
JF - Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis
N2 - 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.
KW - HTHP
KW - Nanohybrid
KW - Poylaniline
KW - Multiwalled carbon nanotube
Y1 - 2015
U6 - https://doi.org/10.1002/elan.201500231
SN - 1040-0397
SN - 1521-4109
VL - 27
IS - 10
SP - 2262
EP - 2267
PB - Wiley-VCH
CY - Weinheim
ER -
TY - JOUR
A1 - Yarman, Aysu
A1 - Kurbanoğlu, Sevinç
A1 - Zebger, Ingo
A1 - Scheller, Frieder W.
T1 - Simple and robust
BT - the claims of protein sensing by molecularly imprinted polymers
JF - Sensors and actuators : B, Chemical : an international journal devoted to research and development of chemical transducers
N2 - 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.
KW - Molecularly imprinted polymer
KW - Plastibodies
KW - Functional scaffolds
KW - Biomimetic sensors
KW - Proteins
Y1 - 2021
U6 - https://doi.org/10.1016/j.snb.2020.129369
SN - 0925-4005
SN - 1873-3077
VL - 330
PB - Elsevier Science
CY - Amsterdam [u.a.]
ER -
TY - JOUR
A1 - Caserta, Giorgio
A1 - Zhang, Xiaorong
A1 - Yarman, Aysu
A1 - Supala, Eszter
A1 - Wollenberger, Ulla
A1 - Gyurcsányi, Róbert E.
A1 - Zebger, Ingo
A1 - Scheller, Frieder W.
T1 - Insights in electrosynthesis, target binding, and stability of peptide-imprinted polymer nanofilms
JF - Electrochimica acta : the journal of the International Society of Electrochemistry (ISE)
N2 - 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.
KW - SEIRA spectroelectrochemistry
KW - peptide imprinting
KW - electrosynthesis
KW - MIP
KW - glycated peptide
Y1 - 2021
U6 - https://doi.org/10.1016/j.electacta.2021.138236
SN - 0013-4686
SN - 1873-3859
VL - 381
PB - Elsevier
CY - New York, NY [u.a.]
ER -
TY - GEN
A1 - Peng, Lei
A1 - Yarman, Aysu
A1 - Jetzschmann, Katharina J.
A1 - Jeoung, Jae-Hun
A1 - Schad, Daniel
A1 - Dobbek, Holger
A1 - Wollenberger, Ursula
A1 - Scheller, Frieder W.
T1 - Molecularly imprinted electropolymer for a hexameric heme protein with direct electron transfer and peroxide electrocatalysis
N2 - 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).
T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 362
KW - molecularly imprinted polymers
KW - self-assembled monolayer
KW - direct electron transfer
KW - hydrogen peroxide
KW - bioelectrocatalysis
Y1 - 2017
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-400627
ER -
TY - JOUR
A1 - Peng, Lei
A1 - Yarman, Aysu
A1 - Jetzschmann, Katharina J.
A1 - Jeoung, Jae-Hun
A1 - Schad, Daniel
A1 - Dobbek, Holger
A1 - Wollenberger, Ursula
A1 - Scheller, Frieder W.
T1 - Molecularly Imprinted Electropolymer for a Hexameric Heme Protein with Direct Electron Transfer and Peroxide Electrocatalysis
JF - SENSORS
N2 - 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).
KW - hydrogen peroxide
KW - bioelectrocatalysis
KW - molecularly imprinted polymers
KW - direct electron transfer
KW - self-assembled monolayer
Y1 - 2016
U6 - https://doi.org/10.3390/s16030272
SN - 1424-8220
VL - 16
SP - 1343
EP - 1364
PB - MDPI
CY - Basel
ER -
TY - JOUR
A1 - Zhang, Xiaorong
A1 - Caserta, Giorgio
A1 - Yarman, Aysu
A1 - Supala, Eszter
A1 - Tadjoung Waffo, Armel Franklin
A1 - Wollenberger, Ulla
A1 - Gyurcsanyi, Robert E.
A1 - Zebger, Ingo
A1 - Scheller, Frieder W.
T1 - "Out of Pocket" protein binding
BT - a dilemma of epitope imprinted polymers revealed for human hemoglobin
JF - Chemosensors
N2 - 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.
KW - Molecularly Imprinted Polymers
KW - epitope imprinting
KW - non-specific
KW - binding
KW - redox gating
KW - SEIRA spectroelectrochemistry
Y1 - 2021
U6 - https://doi.org/10.3390/chemosensors9060128
SN - 2227-9040
VL - 9
IS - 6
PB - MDPI
CY - Basel
ER -
TY - JOUR
A1 - Menger, Marcus
A1 - Yarman, Aysu
A1 - Erdössy, Júlia
A1 - Yildiz, Huseyin Bekir
A1 - Gyurcsányi, Róbert E.
A1 - Scheller, Frieder W.
T1 - MIPs and Aptamers for Recognition of Proteins in Biomimetic Sensing
JF - Biosensors : open access journal
N2 - 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.
KW - biomimetic recognition elements
KW - aptamers
KW - molecularly imprinted polymers
KW - chemical sensors
KW - aptasensors
KW - in vitro selection
KW - SELEX
Y1 - 2016
U6 - https://doi.org/10.3390/bios6030035
SN - 2079-6374
VL - 6
SP - 4399
EP - 4413
PB - MDPI
CY - Basel
ER -
TY - GEN
A1 - Menger, Marcus
A1 - Yarman, Aysu
A1 - Erdőssy, Júlia
A1 - Yildiz, Huseyin Bekir
A1 - Gyurcsányi, Róbert E.
A1 - Scheller, Frieder W.
T1 - MIPs and aptamers for recognition of proteins in biomimetic sensing
N2 - 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.
T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 357
KW - biomimetic recognition elements
KW - aptamers
KW - molecularly imprinted polymers
KW - chemical sensors
KW - aptasensors
KW - in vitro selection
KW - SELEX
Y1 - 2017
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-400496
ER -