Facile and controllable electrochemical fabrication of cell-adhesive polypyrrole electrodes using pyrrole-RGD peptides

Abstract

Electrically conductive polymers, such as polypyrrole (PPy), have been widely used for the fabrication of various biosensors and tissue engineering scaffolds. For their biologically relevant applications, conductive biomaterials capable of intimate cellular interactions are highly desired. However, conventional methods to incorporate biomolecules into conductive polymers do not offer fine and easy control over the surface density of the biomolecules and/or their stability. We present a novel method to electrochemically immobilize cell-adhesive Arg-Gly-Asp (RGD) ligands on PPy electrode surfaces with a simple control over the peptide surface density by varying the electrodeposition time. Synthesized pyrrole-GGGRGDS conjugates were electrochemically incorporated onto the surfaces of PPy-coated electrodes. The electrochemical impedances of the RGD-grafted PPy electrodes were not significantly different from the unmodified PPy films. Time-of-flight secondary-ion mass spectroscopy confirmed the presence of the RGD motif on the surface of the modified electrodes. In vitro studies with human mesenchymal stem cells (hMSCs) showed higher adhesion and faster proliferation of hMSCs on the PPy with a higher RGD density. This facile electrochemical modification of electrode surfaces allowed for a good control over the peptide surface density and cellular interactions and will benefit the fabrication of cell-interactive scaffolds or bio-electrodes.

Mussel-inspired conductive nanofibrous membranes repair myocardial infarction by enhancing cardiac function and revascularization

“…During the process of oxidative polymerization of Ppy, the pendant methacrylate groups of GelMA formed a self-crosslinked network 4 , 56 , helping the formation of spherical GelMA-Ppy nanoparticles. It seems that Ppy does not provide cell-interactive moieties, and the self-crosslinked network of GelMA-Ppy improves the cytocompatibility of Ppy 43 , 57 . The incorporation of GelMA in GelMA-Ppy nanoparticles was bifunctional, keeping the nanoparticles conductive and promoting cell survival.…”

“…Higher than 9.7 µg/mL Ppy polymerized by oxidative doping has been considered harmful for cell viability/proliferation 42 . A recent in vitro study reported that polypeptide-conjugated Ppy-coated metal electrode displays excellent cytocompatibility 43 , 44 . Gelatin, a natural polymer, can be self-crosslinked into a monomolecular or network structure in dilute solutions 45 - 47 .…”

Electrically Conductive Polydopamine–Polypyrrole as High Performance Biomaterials for Cell Stimulation in Vitro and Electrical Signal Recording in Vivo

“…This poor cell growth is frequently observed when using PPY-based materials. 33 By comparison the PDA/PPY samples supported myoblast growth, with significantly more cells observed on PDA/PPY (50 mC) compared to the other PDA/PPY samples prepared with 100 mC, 200 mC, and 300 mC charges. Myoblast numbers on the thin PPY and all PDA/PPY substrates increased over 7 days of culture.…”

“…31,32 PPY biomaterials has been further modified by creating specific topographies, incorporating biomolecules (e.g., peptides, proteins, and polysaccharides), and modulating mechanical properties to improve their biological interactions. 28,31,33,34 Despite the unique benefits of CP-modified electrodes, their biocompatibility is often compromised by electrochemical functions (e.g. thick CP coatings can decrease the electrical impedance of electrodes but lead to poor cell attachment and growth).…”

Biofabrication Using Electrochemical Devices and Systems

“…Jang et al reported an approach to electrochemically immobilize cell‐adhesive RGD ligands on PPy electrode surfaces. The surface peptide density was simply controlled by varying the electrodeposition time, and the hMSCs showed enhanced adhesion and proliferation on the PPy films with RGD peptides 56. This approach is useful for the fabrication of cell‐interactive scaffolds or bio‐electrodes.…”