Organically modified polyaniline for physiological fluids operatable supercapacitor electrodes

Recent developments in implantable electronic medical devices have prompted an increasing demand for energy storage devices which are operatable in physiological fluids. Fabrication of such devices requires materials that are electroactive in physiological fluids and biocompatible. Herein, organically modified polyaniline derivative (PANI-der), which is inherently redox active at neutral pH, was evaluated as an electrode material for physiological fluids operatable supercapacitor. PANI-der displayed high specific capacitance and energy density in physiological fluids (phosphate buffer solution, blood, serum, urine and sweat) and culture media (DMEM and LB broth). For instance, in blood, PANI-der displayed a specific capacitance of 305 F/g which is 254 times higher than that of conventional PANI. Biocompatibility of PANI-der towards L929 cells was analyzed by MTT assay, where it displayed cell viability of 92.11 ± 5.84 % confirming its biocompatibility. Further, PANI-der exhibited good cyto-compatibility during voltage cycling in A549 cell lines where 96.8 % cell viability was retained even after 1000 galvanostatic charge–discharge cycles. Owing to inherent redox activity in physiological fluids and biocompatibility, PANI-der has potential for integration with in vivo medical devices.