Anti-aging has become an important research topic in the field of modern life science. Hydrogels are interesting to consider for anti-aging applications due to their unique structure. In recent years, novel hydrogels based on marine-derived sustainable materials have been widely applied in the field of biomedicine owing to their good biocompatibility, low toxicity, and high biodegradability. They can also help the body to fight oxidation and regulate the expression of senescence-related genes. Although a lot of chitosan (CS)-based hydrogels have been developed and studied for anti-aging, few hydrogels are approved for clinical application. Here, we aim to develop a new type of multi-functional thermosensitive polysaccharide nanoparticle-reinforced chitosan-based hydrogel with anti-aging bioactive factors, which has excellent mechanical properties, appropriate degradation rate, good skin absorption, and high anti-aging efficiency.
Sustainable CS obtained from the shells of shrimps was used to develop the promising thermoresponsive polymer, hydroxybutyl chitosan (HBC). HBC was synthesized by conjugation of hydroxybutyl groups to the hydroxyl and amino reactive sites of CS. HBC hydrogel has a lower critical solution temperature (LCST) and undergoes sol-gel transition at body temperature. These properties can be easily regulated by changes in the concentration of HBC. With increasing the concentration of HBC, the hydrogel exhibited lower gelation temperature, shorter gelation time, higher crosslinking density, and higher mechanical strength. Evaluation of the morphology using scanning electron microscopy (SEM) indicated that HBC hydrogels exhibited connected porous networks, which had smooth surfaces. Biological tests in vitro showed that high-concentration HBC hydrogels are non-cytotoxic to L929 cells. Thus, HBC hydrogels have potential applications in biomedical fields.
Marine-derived polysaccharide nanoparticles (PNPs) can be used as a reinforcing biomass-based filler, drug carrier, and anti-aging agent.
Chitosan nanoparticles (CSNPs) were synthesized by the ionic gelation method. CSNPs exhibited a mean diameter of 213.2 nm in narrow size distribution (PDI = 0.224) by the dynamic light scattering (DLS) analysis. The mean zeta potential was about +23.8 mV. SEM images indicated that the prepared CSNPs had a solid rod-like shape and smooth surface.
Other CS-based hydrogels were prepared by using crosslinkers 3-Glycidyloxypropyl Trimethoxysilane (GPTMS) and genipin. Compared to genipin, GPTMS is a better cross-linking agent with higher cell viability and better cell attachment observed using L929 fibroblasts.
The good biocompatibility of GPTMS crosslinked chitosan hydrogels lays the foundation for its use in biomaterials application.
In the first year, we have successfully synthesized thermosensitive hydrogel substrates and nanoparticles. It provides the foundation for the development of novel anti-aging hydrogels. The biodegradability, biocompatibility, anti-inflammation effect, skin absorption as well as anti-aging mechanisms of the hydrogel will be deeply investigated in future work. Finally, we will seek the potential clinical applications of these novel hydrogels.