Electroconductive and injectable hydrogels based on gelatin and PEDOT:PSS for mini-invasive approaches in nervous tissue regeneration

This work describes the development of electroconductive hydrogels as injectable matrices for neuraltissue regeneration by exploiting a biocompatible conductive polymer - poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) - combined with a biomimetic polymer network made ofgelatin. Our approach involved also genipin - a natural cross-linking agent - to promote gelation ofgelatin networks embedding PEDOT:PSS. The achieved results suggest that physical-chemical propertiesof the resulting hydrogels, like impedance, gelation time, mechanical properties, swelling and degradationin physiological conditions, can be finely tuned by the amount of PEDOT:PSS and genipin used in the formulation.Furthermore, the presence of PEDOT:PSS (i) enhances the electrical conductivity, (ii) improvesthe shear modulus of the resulting hydrogels though (iii) partially impairing their resistance to shear deformation,(iv) reduces gelation time and (v) reduces their swelling ability in physiological medium.Additionally, the resulting electroconductive hydrogels demonstrate enhanced adhesion and growth ofprimary rat cortical astrocytes. Given the permissive interaction of hydrogels with primary astrocytes, thepresented biomimetic, electroconductive and injectable hydrogels display potential applications as minimallyinvasive systems for neurological therapies and damaged brain tissue repair.