Investigation of the electrical properties of composite fibers based on chitosan and polypyrrole for tissue engineering

Composite fibers based on chitosan, coated with a conducting polymer, polypyrrole (PPyr), have been obtained. Their morphology was studied by scanning electron microscopy. The electrical conductivity of the fibers in a dry state and in a liquid culture medium simulating tissue fluid has been estimated. The values of resistivity, $\rho$, and conductivity, $\sigma$, of the investigated fibers are determined depending on the number of PPyr layers, the degree of drawing (orientation) of the fibers in dry and in liquid media. It was found that with an increase in the amount of drawing from 0 to 100%, $\rho$ of fibers decreases both in a dry state and in a liquid culture medium. In this case, the maximum drop $\rho$ of fibers upon immersion in a liquid culture medium was observed for undrawn fibers with two layers of PPyr. It was shown that after an initial drop in $\rho$ of oriented chitosan fibers with 1 and 2 layers of PPyr $\rho$ changes weakly in a liquid culture medium for 2 hours. The investigated oriented polymer fibers of chitosan coated with 1 and 2 layers of PPyr are promising for use in the field of tissue engineering and regenerative medicine.