A conductive and biodegradable hydrogel for minimally delivering adipose-derived stem cells

Abstract

Injectable hydrogel is one of the most important biomaterials for tissue engineering and drug delivery. However, it is still a challenge to obtain an injectable hydrogel with conductive property on account of the poor water solubility of conductive polymers Here, a conductive hydrogel with controllable biodegradability was constructed for minimally delivering adipose mesenchymal stem cells (ADSCs). Firstly, a disulfide containing and hyperbranched polymer structure poly(β-amino ester) (PBAE) with multi-acrylate end groups was synthesized by poly(ethylene glycol) diacrylate(PEGDA) and cystamine, and then tetraaniline (TA) was grafted on the PBAE chain to obtain a conductive PBAE-TA polymer. PBAE-TA shows a good water solubility, which can be crosslinked by thiol-modified hyaluronic acid (HA-SH) due to the click reaction between acrylate and thiol to in situ form a hydrogel within 1 min. The hydrogel illustrates a good electrical conductivity of 9.6×10−3 S/cm and a controllable biodegradable behavior in dithiothreotol (DTT) solution. PBAE-TA HA-SH hydrogel was subcutaneously injected for delivering ADSCs. The gene expression of Cx43 and TGF-β1 were up-regulated by PBAE-TA/HA-SH hydrogel, suggesting an enhancement in the electrical coupling and an anti-inflammatory property. This injectable, biodegradable, and conductive hydrogel can effectively deliver stem cells, which might be used in skin, muscle, and myocardium regeneration.