Electroconductive Gels for Controlled Electrorelease of Bioactive Peptides

We have synthesized highly hydrophilic, chemically responsive materials we call electroconductive gels. They are formed as an interpenetrating network of an electroconductive polymer and a hydrophilic hydrogel. Polymers were formulated form UV polymerizable hydrophilic monomer such as hydroxyethyl methacrylate (HEMA), N-[tris(hydroxymethyl)methyl] acrylamide (HMMA), and tetraethylene glycol diacrylate (TEGDA), and oxidatively polymerizable electroactive monomer such as aniline and dianiline. The hydrogel network was formed by UV-photoinitiated polymerization and the electroconductive polymer subsequently formed by chemical oxidative coupling induced by immersion in aqueous FeCl₃ solutions, by electropolymerization, or by a combination of these methods. Interaction between both networks was accorded by the difunctional 3-sulfopropylmethacrylate (SPM). These materials retain more electroactivity and display fast cation transport with K⁺ diffusivity (D_o=5.31×10^-7 cm² s^-1) that are an order of magnitude larger than that of electropolymerized polyaniline (D_o=3.12×10^-8 cm² s^-1). The electroconductive polyaniline gels are shown to be more stable under ambient conditions and to efficiently imbibe and release Ca⁺⁺ under electrostimulation.