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  - 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  - 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  -