A sustainable and nondestructive method to high-throughput decolor Lycium barbarum L. polysaccharides by graphene-based nano-decoloration

Lycium barbarum L. polysaccharides (LBPs) with outstanding biological activities are of increasing interest. Traditional purification approaches are time-consuming and often involve toxic solvents that destroy the functionality and structure of polysaccharides. Herein, we report a sustainable and nondestructive strategy for purifying LBPs using graphene-based nano-decoloration. The amination of graphene oxide (GO) enables the resulted aminated reduced GO (NH 2 -rGO) with abundant sp 2 -hybridized carbon domains, displaying high adsorption capacity toward pigments in crude polysaccharides. As such, within 5 min, NH 2 -rGO can highly effectively and fast to decolor LBPs, with a high decoloration ratio of 98.72% and a high polysaccharides retention ratio of 95.62%. Importantly, compared with traditional decoloration methods, NH 2 -rGO is nondestructive toward LBPs and has good reusability. Moreover, it exhibited widespread-use decoloration performance to decolor several common plant species. Overall, our proposed nano-decoloration approach is a general-purpose, sustainable, and nondestructive method to purify LBPs.