Electrical properties of biodegradable chitosan-calcium phosphate nerve conduits doped with inorganic nanoparticles

Abstract

Biodegradable nerve conductors are based on chitosan-calcium phosphate (CS/CaP) doped with nanoparticles of multiwalled carbon nanotubes (MWCNT+Fe), graphene oxide (GO), magnetite (Fe3O4) of various nanoparticle concentrations (NpC). Drug release and electrical properties were studied depending on the polarity, voltage, and electrode configuration (in-in, in-out), which reflect nerve regeneration inside the conduit and external electrical stimulation. The NpC of 150 μg/ml provides the highest electrical conductivity (EC) of 150MWCNT+Fe in-in. 150GO is more effective in the in-out configuration. The 300GO sample has an in-out electrical conductivity of 0.71∙ 10−2 S/cm, which is close to the natural nerve conductivity of 2.35∙10−2 S/cm. Nanoparticles in the CS/CaP matrix when interacting with the physiological solution ions can create new mechanisms for the current passage or neutralize existing ones. All samples are characterized by the absence of "burst drug release". Pregabalin (PG) release from Fe-containing samples is controlled by diffusion (first-order model), and from GO-containing – by diffusion and degradation of the matrix (second-order model).