Hybrid Conducting Composite Films Based on Polypyrrole and Poly(2-(diethylamino)ethyl methacrylate) Hydrogel Nanoparticles for Electrochemically Controlled Drug Delivery

A 3D conductive hybrid film is fabricated based on poly 2-(diethylamino) ethyl methacrylate (PDEA) nanoparticles with polypyrrole (PPy) as the conductive component. PDEA nanoparticles are deposited on a gold substrate by drop casting. Then, PPy is electrochemically grown through the hydrogel nanoparticles as a semi-interpenetrating polymer network. PDEA hydrogel nanoparticles reversibly swell at low pH while PPy liberates H+ in the oxidized state. The oxidation of PPy is used to create an electrostimulated decrease in pH in the PDEA/PPy hybrid film that results in film swelling. The electrochemical properties of the hybrid conductive composite film are studied through cyclic voltammetry and electrochemical impedance spectroscopy. Doxorubicin (Dox) as model drug is encapsulated in the PDEA/PPy hybrid composite film by a pH switch. Drug electroliberation is investigated at different applied potentials from -0.65 to +0.65 V. The amount of Dox released shows a dependence on the applied potential and the duration of the electrical stimuli. The (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) tetrazolium reduction assay is conducted to evaluate the impact of the electrocontrolled release of Dox on the proliferation of the A549 cell line, showing a decrease in cell viability, proportional to the applied potential and its duration.