Contribution to the Understanding of the Interaction between a Polydopamine Molecular Imprint and a Protein Model: Ionic Strength and pH Effect Investigation

Several studies were devoted to the design of molecularly imprinted polymer (MIP)-based sensors for the detection of a given protein. Here, we bring elements that could contribute to the understanding of the interaction mechanism involved in the recognition of a protein by an imprint. For this purpose, a polydopamine (PDA)-MIP was designed for bovine serum albumin (BSA) recognition. Prior to BSA grafting, the gold surfaces were functionalized with mixed self-assembled monolayers of (MUDA)/(MHOH) (1/9, v/v). The MIP was then elaborated by dopamine electropolymerization and further extraction of BSA templates by incubating the electrode in proteinase K solution. Three complementary techniques, electrochemistry, zetametry, and Fourier-transform infrared spectrometry, were used to investigate pH and ionic strength effects on a MIP’s design and the further recognition process of the analytes by the imprints. Several MIPs were thus designed in acidic, neutral, and basic media and at various ionic strength values. Results indicate that the most appropriate conditions, to achieve a successful MIPs, were an ionic strength of 167 mM and a pH of 7.4. Sensitivity and dissociation constant of the designed sensor were of order of (3.36 ± 0.13) µA·cm−2·mg−1·mL and (8.56 ± 6.09) × 10−11 mg/mL, respectively

Highly Selective Polypyrrole MIP-Based Gravimetric and Electrochemical Sensors for Picomolar Detection of Glyphosate

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Design of Novel Electrochemical Sensors for the Selective Detection of Glyphosate

International audienceThis study concerns the development of two molecularly imprinted polymers (MIP) based electrochemical sensors for glyphosate detection. In both cases polypyrrole (PPy) was chosen as matrix and glyphosate molecules were the templates. The main difference between the two strategies is related to the investigated electrode: gold surface in the first case, and ZnO nanorods vertically grown on ITO diazonium modified substrates in the second case. The limits of detection (LOD) of these sensors were about 10−13 M and 10−10 M respectively

Computational approach and electrochemical measurements for protein detection with MIP-based sensor

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Design of L-Cysteine and Acrylic Acid Imprinted Polypyrrole Sensors for Picomolar Detection of Lead Ions in Simple and Real Media

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Electrochemical and optical investigation of dental pulp stem cell adhesion on modified porous silicon scaffolds

International audienceExtensive use of porous silicon (PSi) for tissue engineering is due to its convenient properties as it is both non-toxic and bioresorbable. Moreover, PSi surface modification is an important step to enhance cell adhesion and proliferation. In this work, a combination of optical and electrochemical studies is performed to elaborate a suitable PSi multilayer substrate for cell culture. For this study, we modified PSi surface by silanization and antibody grafting (APTES-anti STRO1), the 12-mer specific peptide to silicon p+type coating and the peptide modified with the antibody recognition sequence. Electrochemical characterization of PSi multilayers is performed to investigate its electrical behavior, determine the optimal measuring conditions and reveal the most stable PSi surfaces. Then, the behavior of dental pulp stem cells (DPSC) was investigated on various modified PSi surfaces. An electrochemical method was applied for the first time monitoring the electrical behavior of stem cell adhesion. The cells electrochemical behavior depends on the nature of the surface coating and the peptide-anti STRO1 improved adhesion and cell spreading onto the PSi surface compared to bare surface and the one coated with the peptide. Fluorescent microscopy revealed that all surface modi cation methods enhance cell adhesion compared to the bare PSi surface. An increased cell number is observed on APTES-anti STRO1, peptide and peptide-anti STRO1 coated PSi. The peptide-anti STRO1 provided the best cell proliferation results suggesting the improved accessibility of the recognition fragment of the antibody anti-STRO1

Ultrasensitive Ion Imprinted Polypyrole Polymer Based Piezoelectric Sensors for Selective Detection of Lead Ions

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Ultrasensitive Ion Imprinted Polypyrole Polymer Based Piezoelectric Sensors for Selective Detection of Lead Ions

International audienceSurface acoustic wave sensors functionalized with a thin layers of polypyrrole ionic imprinted polymer were designed and realized for the selective detection of lead ions. Polypyrrole films were electrodeposited on gold surface and acrylic acid was used as a chelating agent. Detection of the analyte is ensured by the strong affinity between carboxylic groups and lead ions. The detection limit of, the developed IIP piezoelectric sensor was of order of 0.1 pM, largely inferior to the maximum allowable concentration required by the European Commission for lead and its compounds (of order of 0.48 μM). Selectivity tests investigated with cobalt, copper, mercury and nickel ions, indicate that the designed sensors are selective of lead ions