Refine
Year of publication
Document Type
- Article (246)
- Postprint (7)
- Review (7)
- Other (2)
- Monograph/Edited Volume (1)
- Doctoral Thesis (1)
Is part of the Bibliography
- yes (264) (remove)
Keywords
- molecularly imprinted polymers (15)
- Molecularly imprinted polymers (5)
- Biosensors (4)
- Direct electron transfer (4)
- Electropolymerization (4)
- biomimetic sensors (4)
- direct electron transfer (4)
- electropolymerization (4)
- Cytochrome P450 (3)
- Molecularly imprinted polymer (3)
- bioelectrocatalysis (3)
- hydrogen peroxide (3)
- Bioelectrocatalysis (2)
- Biomimetic sensors (2)
- Cytochrome c (2)
- Epitope imprinting (2)
- Microperoxidase-11 (2)
- Nanoparticles (2)
- Proteins (2)
- Redox marker (2)
- SEIRA spectroelectrochemistry (2)
- SELEX (2)
- Scopoletin (2)
- anticancer drug (2)
- aptamers (2)
- aptasensors (2)
- biomimetic recognition elements (2)
- butyrylcholinesterase (2)
- catalysis (2)
- chemical sensors (2)
- electron transfer (2)
- electropolymerisation (2)
- enzymatic MIP synthesis (2)
- enzymatic analyte conversion (2)
- enzyme tracer (2)
- gate effect (2)
- immobilization (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)
- Agrocybe aegerita peroxygenase (1)
- Aniline (1)
- Aniline biosensor (1)
- Antimalarial drug detection (1)
- Artemisinin (1)
- Au nanoparticles (1)
- Biomarker (1)
- Catalytically active MIPs (1)
- Catalytically active molecularly imprinted polymers (1)
- Catechol (1)
- Cellobiose dehydrogenase (1)
- Concanavalin A (1)
- Daptomycin (1)
- Displacement (1)
- Electro-synthesized molecularly imprinted polymer (1)
- Electrochemical sensor (1)
- Enzymatic recycling (1)
- Enzyme catalysis (1)
- Escherichia coli (1)
- Esterase (1)
- Ferritin (1)
- Ferrocene benzoboroxol biosensor (1)
- Ferrocene boronic acid (1)
- Functional scaffolds (1)
- HTHP (1)
- Hangman porphyrin (1)
- Hexokinase (1)
- Human serum albumin (1)
- Hybrid nanofilms (1)
- Hydrogen peroxide (1)
- Immobilization (1)
- Japan (1)
- Karube (1)
- MIP (1)
- Mercaptoundecanoic acid (1)
- Metalloenzymes (1)
- Microperoxidase (1)
- Microperoxidases (1)
- Molecularly Imprinted Polymers (1)
- Molecularly imprinted polymer film (1)
- Monoclonal MIPs (1)
- Multiwalled carbon nanotube (1)
- Nanohybrid (1)
- Nanostructuring (1)
- Osmium (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)
- Scopoletin (7-hydroxy-6-methoxycoumarin) (1)
- Self-assembled monolayer (1)
- Superoxide (1)
- Surface imprinting (1)
- Third generation sensor (1)
- Transferrin (1)
- Tyrosinase (1)
- Unspecific peroxygenase (1)
- Urine (1)
- acetylcholinesterase (1)
- activation of oxygen species (1)
- artificial protein binders (1)
- binding (1)
- biosensors (1)
- cancer markers (1)
- cobalt porphyrin (1)
- computationally simulated epitopes (1)
- cytochrome P450 (1)
- cytochrome c (1)
- direct electron (1)
- drug imprinting (1)
- drug sensors (1)
- electro-polymerization (1)
- electrochemical sensors (1)
- electrochemistry (1)
- electropolymers (1)
- electrosynthesis (1)
- enzymes (1)
- epitope imprinting (1)
- glycated peptide (1)
- gold (1)
- heme proteins (1)
- heterogeneous catalysis (1)
- hierarchical structures (1)
- horseradish peroxidase (1)
- lifetime achievements (1)
- modified electrodes (1)
- molecular imprinting (1)
- molecular modeling (1)
- molecularly imprinted electropolymers (1)
- molecularly imprinted polymer (1)
- monolayers (1)
- multilayer (1)
- nanoparticles (1)
- non-specific (1)
- o-Phenylenediamine (1)
- p-Aminophenol (1)
- peptide imprinting (1)
- peripheral anionic site (1)
- platinum nanoparticles (1)
- propidium (1)
- protein imprinting (1)
- protein recognition (1)
- redox gating (1)
- sulfite (1)
- sulfite oxidase (1)
- transfer (1)
Widely used diagnostic tools make use of antibodies recognizing targeted molecules, but additional techniques are required in order to alleviate the disadvantages of antibodies. Herein, molecular dynamic calculations are performed for the design of high affinity artificial protein binding surfaces for the recognition of neuron specific enolase (NSE), a known cancer biomarker. Computational simulations are employed to identify particularly stabile secondary structure elements. These epitopes are used for the subsequent molecular imprinting, where surface imprinting approach is applied. The molecular imprints generated with the calculated epitopes of greater stability (Cys-Ep1) show better binding properties than those of lower stability (Cys-Ep5). The average binding strength of imprints created with stabile epitopes is found to be around twofold and fourfold higher for the NSE derived peptide and NSE protein, respectively. The recognition of NSE is investigated in a wide concentration range, where high sensitivity (limit of detection (LOD) = 0.5 ng mL(-1)) and affinity (dissociation constant (K-d) = 5.3 x 10(-11)m) are achieved using Cys-Ep1 imprints reflecting the stable structure of the template molecules. This integrated approach employing stability calculations for the identification of stabile epitopes is expected to have a major impact on the future development of high affinity protein capturing binders.
A new approach for synthesizing a vectorially imprinted polymer (VIP) is presented for the microbial cytochrome P450cam enzyme. A surface attached binding motif of a natural reaction partner of the target protein, putidaredoxin (Pdx), is the anchor to the underlying transducer. The 15 amino acid peptide anchor, which stems from the largest continuous amino acid chain within the binding site of Pdx was modified: (i) internal cysteines were replaced by serines to prevent disulfide bond formation; (ii) 2 ethylene glycol units were attached to the N-terminus as a spacer region; and (iii) an N-terminal cysteine was added to allow the immobilization on the gold electrode surface. Immobilization on GCE was achieved via an N-(1-pyrenyl)maleimide (NPM) cross-linker. In this way oriented immobilization of P450cam was accomplished by binding it to a peptide-modified gold or glassy carbon electrode (GCE) prior to the electrosynthesis of a polymer nanofilm around the immobilized target. This VIP nanofilm enabled reversible oriented docking of P450cam as it is indicated by the catalytic oxygen reduction via direct electron transfer between the enzyme and the underlying electrode. Catalysis of oxygen reduction by P450cam bound to the VIP-modified GCE was used to measure rebinding to the VIP. The mild coupling of an oxidoreductase with the electrode may be appropriate for realizing electrode-driven substrate conversion by instable P450 enzymes without the need of NADPH co-factor.
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.
The thiophene-modified iron porphyrin FeT3ThP and the respective iron Hangman porphyrin FeH3ThP, incorporating a carboxylic acid hanging group in the second coordination sphere of the iron center, were electropolymerized on glassy carbon electrodes using 3,4-ethylenedioxythiophene (EDOT) as co-monomer. Scanning electron microscopy images and Resonance Raman spectra demonstrated incorporation of the porphyrin monomers into a fibrous polymer network. Porphyrin/polyEDOT films catalyzed the reduction of molecular oxygen in a four-electron reaction to water with onset potentials as high as +0.14V vs. Ag/AgCl in an aqueous solution of pH7. Further, FeT3ThP/polyEDOT films showed electrocatalytic activity towards reduction of hydrogen peroxide at highly positive potentials, which was significantly enhanced by introduction of the carboxylic acid hanging group in FeH3ThP. The second coordination sphere residue promotes formation of a highly oxidizing reaction intermediate, presumably via advantageous proton supply, as observed for peroxidases and catalases making FeH3ThP/polyEDOT films efficient mimics of heme enzymes.
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.
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.
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.
This study aims to develop a rapid, sensitive and cost-effective biomimetic electrochemical sensor for artemisinin determination in plant extracts and for pharmacokinetic studies. A novel molecularly imprinted polymer (MIP)based electrochemical sensor was developed by electropolymerization of o-phenylenediamine (o-PD) in the presence of artemisinin on gold wire surface for sensitive detection of artemisinin. The experimental parameters, including selection of functional monomer, polymerization conditions, template extraction after polymerization, influence of pH and buffer were all optimized. Every step of imprinted film synthesis were evaluated by employing voltammetry techniques, surface-enhanced infrared absorption spectroscopy (SEIRAS) and atomic force microscopy (AFM). The specificity was further evaluated by investigating non-specific artemisinin binding on non-imprinted polymer (NIP) surfaces and an imprinting factor of 6.8 was achieved. The artemisinin imprinted polymers using o-PD as functional monomer have provided highly stable and effective binding cavities for artemisinin. Cross-reactivity studies with drug molecules showed that the MIPs are highly specific for artemisinin. The influence of matrix effect was further investigated both in artificial plant matrix and diluted human serum. The results revealed a high affinity of artemisinin-MIP with dissociation constant of 7.3 x 10(-9) M and with a detection limit of 0.01 mu M and 0.02 mu M in buffer and plant matrix, respectively.
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.
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.