title: Polypyrrole-supported membrane proteins for bio-inspired ion channels.
abstract: Biomedical platforms constructed by immobilizing membrane proteins in matrixes made of synthetic organic polymers is a challenge because the structure and function of these proteins are affected by environmental conditions. In this work, an operative composite that regulates the diffusion of alkali ions has been prepared by functionalizing a supporting matrix made of poly(N-methylpyrrole) (PNMPy) with a β-barrel membrane protein (Omp2a) that forms channels and pores. The protein has been unequivocally identified in the composite, and its structure has been shown to remain unaltered. The PNMPy-Omp2a platform fulfills properties typically associated with functional bio-interfaces with biomedical applications (e.g., biocompatibility, biodegrabadility, and hydrophilicity). The functionality of the immobilized protein has been examined by studying the passive ion transport response in the presence of electrolytic solutions with Na(+) and K(+) concentrations close to those found in blood. Although the behavior of PNMPy and PNMPy-Omp2a is very similar for solutions with very low concentration, the resistance of the latter decreases drastically when the concentration of ions increases to ∼100 mM. This reduction reflects an enhanced ion exchange between the biocomposite and the electrolytic medium, which is not observed in PNMPy, evidencing that PNMPy-Omp2a is particularly well suited to prepare bioinspired channels and smart biosensors.
authors.affiliation: Departament d'Enginyeria Química, ETSEIB, Universitat Politècnica de Catalunya , Avda. Diagonal 647, Barcelona E-08028, Spain.
authors.forename: Maria M
authors.initials: MM
authors.lastname: Pérez-Madrigal
authors.forename: Luis J
authors.initials: LJ
authors.lastname: del Valle
authors.forename: Elaine
authors.initials: E
authors.lastname: Armelin
authors.forename: Catherine
authors.initials: C
authors.lastname: Michaux
authors.forename: Guillaume
authors.initials: G
authors.lastname: Roussel
authors.forename: Eric A
authors.initials: EA
authors.lastname: Perpète
authors.forename: Carlos
authors.initials: C
authors.lastname: Alemán
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000378:metabolism*; D001692:Biological Transport; D002460:Cell Line; D002477:Cells / Q000378:metabolism; D007473:Ion Channels / Q000138:chemical synthesis / Q000378:metabolism*; D007477:Ions / Q000378:metabolism; D011108:Polymers / Q000737:chemistry*; D018272:Porins / Q000737:chemistry* / Q000378:metabolism; D011188:Potassium / Q000378:metabolism; D011758:Pyrroles / Q000737:chemistry*; D012964:Sodium / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D001672:Biocompatible Materials; D007473:Ion Channels; D007477:Ions; C096735:Omp2a protein, Brucella; D011108:Polymers; D018272:Porins; D011758:Pyrroles; C067635:polypyrrole; D012964:Sodium; D011188:Potassium
keywords: bioinspired channels; electroactive polymer; electrochemical impedance spectroscopy; functional bio-interfaces; ion exchange