Sulfonated glycosaminoglycan bioinspired carbon dots for effective cellular labelling and promotion on the differentiation of mesenchymal stem cells
Though carbon dots (CDs) had been synthesized and applied in a variety of biological fields such as disease diagnosis and gene/drug delivery, the exploration on facile bioinspired synthesis and applications of CDs were still of great significance. Particularly, recent increasing researches had clearly confirmed that nanomaterials were able to affect a series of physiological behaviors and functions of mesenchymal stem cells (MSCs) (e.g. differentiation and pluripotency). Therefore, it was very important to develop multifunctional nanomaterials to simultaneously realize the cellular labelling and regulation on MSCs behaviors in practical applications. Herein, a sulfonated glycosaminoglycan bioinspired CDs as bi-functional nanomaterials were ingeniously designed for cellular imaging and promoting the differentiation of rat bone MSCs (rBMSCs) in different culture media. This bifunctional CDs were successfully prepared via one-pot hydrothermal synthesis by using D-glucosamine hydrochloride (GA·HCl) and sodium p-styrenesulfonate (NaSS) as the reactants. The synthesized CDs with uniform particle size (around 4 nm) were prone to be well-dispersed in aqueous solution, and exhibited remarkable fluorescence stability at different conditions. Besides, results of cell viability and proliferation also demonstrated that CDs possessed good biocompatibility, having negligible effects on the self-renewal potential of rBMSCs. The as-prepared CDs presented a cytoplasmatic distribution after ingested by rBMSCs, which made them particularly suitable for cellular imaging. More importantly, the addition of CDs in osteogenic and chondrogenic induction medium (OIM and CIM) respectively was capable of effectively promoting the osteogenic and chondrogenic differentiation of rBMSCs but having no influence on their pluripotency. In brief, this study not only implemented a cellular labeling method based on CDs that were synthesized by a biomimicking strategy, but also paved a new way to regulate the differentiation of MSCs by designing the multifunctional nanomaterials, which would afford extensive development for the facile synthesis and new application of CDs as well as provide some researching foundation for MSCs-based fields.