The development of biosensors mediated by synergistic quenching effect is of great significance for rapid and accurate clinical diagnosis. Hence, we prepared a cyan-emitting fluorescent Si dots for alkaline phosphatase (ALP) detection through the synergistic quenching effect of inner filter effect (IFE) and photo-induced electron transfer (PET). Si dots were prepared by microwave-assisted method, which displayed high quantum yield (28.7%), as well as good physiochemical properties, such as photo-stability, pH stability, and chemical stability. As the hydrolysate of 4-nitrophenyl phosphate disodium salt hexahydrate catalyzed by ALP, both IFE and PET of 4-nitrophenyl to Si dots were used for the turn-off mode detection of ALP. The linear relationships were established between the change of fluorescence intensity and ALP concentration in the range of 0.05 U L-1 to 5.0 U L-1, and 5.0 U L-1 to 80.0 U L-1, respectively. The detection limit was 0.01 U L-1. The synergistic quenching effect caused the turn-off mode detection to be more sensitive, and it can also be used for the accurate detection of ALP in human serum, thereby showing great anti-interference ability in complex environments.
Keywords: ALP detection; Inner filter effect; Photo-induced electron transfer; Si dots; Synergistic quenching effect.
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