pH-responsive injectable polysaccharide hydrogels with self-healing, enhanced mechanical properties based on POSS

Injectable polysaccharide-based hydrogels are widely employed as drug delivery and tissue engineering materials due to the promising biocompatibility and biodegradability, while the mechanical property of polysaccharide hydrogels still requires to be enhanced much for further applications. In the present work, a family of injectable nanocomposite hydrogels were prepared for the first time through the Schiff base reaction between cationic octa (gamma-chloroammoniumpropyl) silsesquioxane (OCAPS), chitosan (CS), and oxidized hydroxypropyl cellulose (HPC). It was found that OCAPS dispersed well in the hydrogels and inhibited the crystallization of CS and HPC, and the resulted nanocomposite hydrogels response pH values by reversible sol-gel transitions, namely as the pH value was less than 4.2, the hydrogels were low viscous solutions; while gelled again in mild and basic conditions. The gelation time of the hydrogels shrank from 80 to 49 s, and the swelling ratio increases from 3.7 to 6.6, along with the increase of OCAPS feed ratio gradually. The incorporation of OCAPS into the system also enhanced the mechanical property of the hydrogels. Compared with the controllable hydrogel without OCAPS, which failed to remain a certain shape for a long time, the nanocomposite hydrogels exhibited an outstanding compression property, and 68.4% of stain, 4.1 kPa of modulus, 97.9 kPa of strength when 40.0 wt% OCAPS was loaded. The rheological investigations suggested that the hydrogels possessed a very stable network, hence a self-healing property. Moreover, the result of Bovine serum albumin (BSA) load and release experiments demonstrated much improved drug load efficiency and cumulative drug release percentage of the nanocomposite hydrogels; the in-vitro degradation and cytotoxicity tests exhibited perfect biodegradability and biocompatibility of the hydrogels. All of these results demonstrate that the OCAPS and polysaccharides based hydrogels endow sound applications in drug carrier and tissue engineering materials.

Automated summary

This study successfully prepared a family of injectable nanocomposite hydrogels through the Schiff base reaction between OCAPS, CS, and HPC, demonstrating good biocompatibility and biodegradability. The addition of OCAPS enhanced the mechanical properties and drug load efficiency of the hydrogels, showing great potential for drug delivery and tissue engineering applications.