Enhanced mechanical and electrical properties of heteroscaled hydrogels infused with aqueous-dispersible hybrid nanofibers.

Despite the widespread use as platforms for various biomedical applications, engineering hydrogels to impart multifunctionality and control physical properties, while closely mimicking the native cellular microenvironment, is still a significant challenge. Herein, nanofibers consisting of hydrophilic and photocrosslinkable biopolymer and conductive polymer (i.e. PEDOT:PSS) are first fabricated via electrospinning, cut into micrometer-lengths, and chemically crosslinked to develop dispersible hybrid nanofiber (dhNF) as heteroscale reinforcing elements for developing nanocomposite hydrogels. The dhNF can be readily dispersed in aqueous precursor solutions without dissolution and incorporated into hydrogels. The resulting 'heteroscale' dhNF-infused hydrogels, consisting of molecular and nanofibrous polymeric network, more closely resembles natural extracellular matrix, and show significant improvement on both mechanical strength and electrical conductivity, by dhNF concentration as well as PEDOT:PSS content in dhNF. These properties not only directly help improve the viability and proliferation of encapsulated cells, but also more effectively relayed external electrical stimulation mediated by enhanced conductivity.