In situ agar–carbomer hydrogel polycondensation: A chemical approach to regenerative medicine

Injectable hydrogels with in situ polycondensation capability are believed as powerful tools to be used in spinal cord injury (SCI) repair: they can be injected using minimally invasive techniques and can conform to any shape. Here, we finely tuned the chemistry of a promising hydrogel, specifically developed for cell and drug delivery purposes in SCI therapeutical strategies, in order to allow its injection through a 40 μm needle at solution state and to let gelation take place inside target tissue, just after injection. A solution was injected in vivo into a mouse spinal cord and consequent in situ gel formation was verified: magnetic resonance imaging showed presence of the polymeric network at injection site and histological analysis, coherently, revealed spherical enclosures in the spinal cord.This hydrogel showed to be a new biocompatible and microinvasive tool that can be used in vivo as a local reservoir for in situ delivery of drugs and cells. This paves the way for the future generation and in vivo experimental validation of new combined tissue engineering approaches.