Refine
Year of publication
Document Type
- Article (26)
- Review (7)
- Postprint (6)
- Doctoral Thesis (1)
Is part of the Bibliography
- yes (40)
Keywords
- molecularly imprinted polymers (14)
- Molecularly imprinted polymers (7)
- Electropolymerization (5)
- biomimetic sensors (5)
- Biosensors (4)
- electropolymerization (4)
- Biomimetic sensors (3)
- Cytochrome P450 (3)
- direct electron transfer (3)
- Direct electron transfer (2)
- Epitope imprinting (2)
- Microperoxidase-11 (2)
- Molecularly imprinted polymer (2)
- Nanoparticles (2)
- Proteins (2)
- Redox marker (2)
- SEIRA spectroelectrochemistry (2)
- SELEX (2)
- Scopoletin (2)
- anticancer drug (2)
- aptamers (2)
- aptasensors (2)
- bioelectrocatalysis (2)
- biomimetic recognition elements (2)
- butyrylcholinesterase (2)
- catalysis (2)
- chemical sensors (2)
- electropolymerisation (2)
- enzymatic MIP synthesis (2)
- enzymatic analyte conversion (2)
- enzyme tracer (2)
- gate effect (2)
- hydrogen peroxide (2)
- in vitro selection (2)
- o-phenylenediamine (2)
- redox marker (2)
- rivastigmine (2)
- self-assembled monolayer (2)
- tamoxifen (2)
- template digestion (2)
- 4-Fluoroaniline (1)
- ATP (1)
- Aniline (1)
- Bioelectrocatalysis (1)
- Biomarker (1)
- Catalytically active MIPs (1)
- Catalytically active molecularly imprinted polymers (1)
- Catechol (1)
- Cellobiose dehydrogenase (1)
- Cytochrome c (1)
- Daptomycin (1)
- Enzymatic recycling (1)
- Esterase (1)
- Functional scaffolds (1)
- HPLC (1)
- HTHP (1)
- Hexokinase (1)
- Hybrid nanofilms (1)
- Hydrogen peroxide (1)
- Laccase (1)
- MIP (1)
- Microperoxidase (1)
- Microperoxidases (1)
- Molecularly Imprinted Polymers (1)
- Monoclonal MIPs (1)
- Multiwalled carbon nanotube (1)
- Nanohybrid (1)
- Nanostructuring (1)
- Paracetamol (1)
- Peroxidatic activity (1)
- Personalised medicine (1)
- Personalized medicine (1)
- Phenacetin (1)
- Phenolic substances (1)
- Plastibodies (1)
- Poylaniline (1)
- Protein adsorption (1)
- Protein imprinting (1)
- Pyruvate kinase (1)
- Superoxide (1)
- Surface imprinting (1)
- Third generation sensor (1)
- Transferrin (1)
- Tyrosinase (1)
- Unspecific peroxygenase (1)
- acetylcholinesterase (1)
- binding (1)
- direct electron (1)
- drug imprinting (1)
- drug sensors (1)
- electrochemical sensors (1)
- electrochemistry (1)
- electron transfer (1)
- electropolymers (1)
- electrosynthesis (1)
- enzymes (1)
- epitope imprinting (1)
- glycated peptide (1)
- gold (1)
- heme proteins (1)
- hierarchical structures (1)
- hydrochlorothiazide (1)
- irbesartan (1)
- modified electrodes (1)
- molecular modeling (1)
- molecularly imprinted electropolymers (1)
- molecularly imprinted polymer (1)
- monolayers (1)
- nanoparticles (1)
- non-specific (1)
- ophenylenediamine (1)
- p-Aminophenol (1)
- peptide imprinting (1)
- peripheral anionic site (1)
- pharmaceutical dosage forms (1)
- platinum nanoparticles (1)
- propidium (1)
- redox gating (1)
- scopoletin (1)
- transfer (1)
- tyrosinase (1)
Institute
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.
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).
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).
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.
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.
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.
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.
Insights in electrosynthesis, target binding, and stability of peptide-imprinted polymer nanofilms
(2021)
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.
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.
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.