Preparation and properties of a fast curing carboxymethyl chitosan hydrogel for skin care

Fast curing hydrogels are highly valuable in the skin care industry. Multi-arm polyethylene glycol (PEG) is a commonly used crosslinking agent for the preparation of fast curing hydrogels. However, the hydrogel preparation using multi-arm PEG crosslinking agents usually requires the end group modifications of reactants, which makes the preparation process complicated and produces hydrogels with low curing rates. In the present study, a fast in situ curing hydrogel, 4-arm-PEG-succinimidyl carbonate/carboxymethyl chitosan (PEG-SC/CMCS), was prepared using 4-arm-PEG-SC as the crosslinking agent and carboxymethyl chitosan (CMCS), a derivative of natural polysaccharide with excellent comprehensive properties, as the framework without any end groups modified. The structure and properties of the prepared hydrogel were characterized by FTIR, XRD, SEM, rheology and swelling kinetics. The effects of reaction conditions on the structure and properties of hydrogel were investigated. The PEG-SC/CMCS hydrogel exhibited pH-sensitive swelling behaviors. Its application potential in skin care products is demonstrated with its excellent sustained-release performance of Vitamin C, a model drug for skin treatment, and high adsorption capacity of heavy metal ions that are easily deposited on skin surface. Our work has provided a new strategy for building multifunctional gel materials for skin care and offered a PEG-SC/CMCS hydrogel with great application potentials.