Bioactive electroconductive hydrogels

A class of bioactive, stimuli-responsive co-joined interpenetrating networks of inherently conductive polymers and highly hydrated hydrogels are being developed for implantable biodevice interfaces and for field induced release of elutable drugs. Polymers were formed from tetraethyleneglycol diacrylate (TEGDA) cross-linked (3-12 mol%) hydroxyethylmethacrylate (HEMA) and N-[tris(hydroxymethyl)methyl]-acrylamide (HMMA) that served as the principal hydrophilic monomers. Polyethylene glycol methacyrlate (PEG₂₀₀MA; 0.3-0.5 mol%) and 2-methacryloyloxyethyl phosphorylcholine (MPC; 5-10 mol%) were introduced to provide in vivo bioactive biocompatibility. Also included was 3-sulfopropyl methacrylate potassium salt (SPMA) that served as the dopant counter anion for oxidatively or electrochemically incorporated polypyrrole (PPy) or polyaniline (PAn). PPy provides interference screening of endogenous interferents in biosensor applications while PAn served as an electro-actuatable polymer for electro-stimulated release of bioactive agents stored within the hydrogel. These bio-device interfaces demonstrate reduced electrical impedance, high RMS 13 and PC12 cell viability (> 80%) and low proliferation (< 40%). Deposition of these electroconductive hydrogel co-networks onto microdisc electrode arrays resulted in enhanced sensitivity and dynamic range for the detection of electroactive species. Bioactive electroconductive hydrogel co-networks were made responsive to glucose and lactate by the inclusion of glucose oxidase and lactate oxidase. Enzyme biosensors showed similar sensitivity but increased current and minimum interference for endogenous interferents.