In situ hydrogel constructed by starch-based nanoparticles via a Schiff base reaction

• Starch nanoparticles with well-defined core–shell structure are obtained.
• In situ hydrogel was formed via Schiff based reaction.
• The introduction of the cholesterol group enhanced the water capacity of hydrogel.
• The introduction of the cholesterol group improved the mechanical strength of hydrogel.
• The OCS hydrogel was a good drug carrier for doxorubicin.

Polysaccharide-based hydrogels are remarkable materials for the biomedical fields because of its excellent biodegradation and biocompatibility. In this work, a novel polysaccharide-based hydrogel was fabricated by in situ crosslinking of starch-based nanoparticles and polyvinylamine. Starch was decorated with cholesterol group and aldehyde groups. TEM and DLS showed that the cholesterol modified oxidation starch (OCS) exhibited a core–shell nanoparticles with mean size of ∼143 nm in aqueous. The hydrogel was then synthesized via Schiff base reaction. Rheological measurements demonstrated the incorporation of cholesterol groups not only reduced the gel time but also improved the storage modulus of the hydrogel compared with the oxide starch crosslinked hydrogel. SEM showed the OCS based hydrogels possess a well-defined porous structure. Furthermore, doxorubicin (DOX) was used as model drug to investigate the control and release properties of OCS hydrogels. This OCS hydrogel would be a promising drug carrier for biomedical applications.