A sensitive polymer dots fluorescent sensor for determination of α-L-fucosidase activity in human serum

α- l -Fucosidase (AFu) is an important biomarker for early diagnosis of hepatocellular carcinoma and fucosidosis. In this study, a novel, sensitive and selective polymer dots (PDs) fluorescent sensing strategy based on inner filter effect was firstly developed for AFu activity determination. The PDs with a high quantum yield of 53.6% were synthesized by a mild one-pot method. The detection mechanism of this strategy was based on inner filter effect between PDs and p-nitrophenol (PNP) which was the hydrolyzate of 4-nitrophenyl-α- l -fucopyranoside (PNPF) catalyzed by AFu. The absorption of PNP overlapped the fluorescence excitation spectrum of the PDs, which resulted in a fluorescence quenching or weakening of PDs. The sensing system showed a good linear relationship within 0.01-0.9 U L −1 and provided a low AFu detection limit of 0.001 U L −1 (S/N = 3). This PDs sensor were successfully applied for the determination of AFu in human serum samples.