writer：Liping Song, L. Zhang, K. Xu, Youju Huang*, P. Gao, H.Y. Fang, J.W. Zhang, Z.H. Nie and Tao Chen*
keywords：Fluorescent Microsphere Probe, Qualitative and Quantitative Detection, Trypsin Activity
source：期刊
specific source：Nanoscale Advances, 2019, 1, 162 - 167
Issue time：2019年

Current technologies still face big challenges to achieve simultaneous rapid qualitative and quantitative detection of trypsin. In our present study, we developed a simple and effective

strategy to sensitively, qualitatively and quantificationally analyze the activity of trypsin, by using fluorescent polystyrene (PS) microsphere probe. The PS spheres were first functionalized by the surface coating of polyethylene glycol (PEG), which can significantly decrease the possibility of nonspecific physical adsorption of fluorescein isothiocyanate isomer modified peptide (peptide-FITC), and then bridge PS-PEG sphere with the peptide-FITC. The

chemically bonded peptide-FITC-PS microspheres were then employed to real-time monitor the activity of trypsin. The peptide was rich in lysine and arginine residues, which were the recognition sites of trypsin. When trypsin was interacting with peptide-FITC-PS microspheres, the peptide-FITC fluorescent would be rapidly decomposed into free small fragments in solution, resulting in the gradual decrease of fluorescent performance of PS spheres. By taking

advantage of fluorescent changes in confocal microscope imaging and fluorescent spectrum intensity, it is easy to achieve qualitative and quantitative detection of trypsin, with a highly sensitive detection limit down to 0.5 ng mL-1 and high selectivity. The designed fluorescent PS microsphere probe would be very promising in various applications such as food safety inspection, personal healthcare and on-site environmental monitoring.