Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710119, China.
Mikrochim Acta. 2022 Jul 15;189(8):282. doi: 10.1007/s00604-022-05378-3.
A new fluorescence method was established for sensitive detection of β-galactosidase (β-gal) activity in spiked human serum and screening of inhibitor. Nitrogen-doped carbon quantum dots (N-CQDs) were prepared by solvothermal polymerization of N-methyl-2-pyrrolidinone in an alkaline condition. The colloidal N-CQDs exhibit good water solubility, stability, and emit bright green fluorescence with a maximum emission peak at 528 nm upon excitation at 420 nm. β-gal specifically catalyzes the decomposition of its substrate P-nitrophenyl-β-D-galactopyranoside into 4-nitrophenol, whose absorption spectrum overlaps well with the excitation spectrum of the N-CQDs. As a result, the fluorescence of the N-CQDs is remarkably quenched by 4-nitrophenol via an inner filter effect. The sensing platform presents a linear response range for β-gal activity from 0.05 to 3.0 U·L with a low limit of detection of 0.023 U·L. An acceptable precision is obtained with a relative standard deviation (RSD) of 3.1% for 1.0 U·L β-gal (n = 11). The method was applied to determine β-gal in spiked human serums with recoveries in the range 96.3-104.7%. The method was employed to evaluate inhibitor screening with D-galactal and chloroquine diphosphate as models.
建立了一种新的荧光法，用于灵敏检测人血清中β-半乳糖苷酶（β-gal）的活性和抑制剂的筛选。通过在碱性条件下将 N-甲基-2-吡咯烷酮进行溶剂热聚合，制备了氮掺杂碳量子点（N-CQDs）。胶体 N-CQDs 具有良好的水溶性、稳定性，在 420nm 激发下，最大发射峰在 528nm 处发出明亮的绿色荧光。β-gal 特异性地催化其底物对硝基苯-β-D-半乳糖吡喃糖苷分解为 4-硝基苯酚，其吸收光谱与 N-CQDs 的激发光谱很好地重叠。因此，4-硝基苯酚通过内滤效应显著猝灭 N-CQDs 的荧光。该传感平台对 β-gal 活性的线性响应范围为 0.05 至 3.0 U·L，检测限低至 0.023 U·L。对于 1.0 U·L β-gal（n=11），相对标准偏差（RSD）为 3.1%，获得了可接受的精密度。该方法已应用于测定人血清中 β-gal 的含量，回收率在 96.3-104.7%之间。该方法用于评估以 D-半乳糖醛和氯喹二磷酸盐为模型的抑制剂筛选。
