Autofluorescence-free detection of trypsin based on persistent luminescent nanospheres and gold nanoparticle aggregation.

Trypsin (Try) is involved in various physiological processes in the human body, and its abnormal expression is associated with certain diseases. Therefore, its simple and accurate detection has important practical significance. Herein, a persistent luminescence sensing system is developed for autofluorescence-free detection of Try based on the blue emitting SiO2/Sr2MgSi2O7:Eu2+ (SSMSE) persistent luminescent nanospheres synthesized by the mSiO2 template method and gold nanoparticle (AuNP) aggregation. Try can specifically hydrolyze peptides in the detection system to produce peptide fragments that can induce the aggregation of AuNPs, which weakens the quenching effect of AuNPs and leads to a decrease in the quenching degree of persistent luminescence of SSMSE, achieving Try detection. The proposed detection system demonstrates a good linear relationship within the range of 1-60 µg L-1 with a low detection limit of 0.40 µg L-1 and the ability to detect Try in actual samples with a recovery rate of 91.2%-106%. The developed method has expanded the use of SSMSE and provides new ideas for Try detection, which has certain practical value.