State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, College of Chemistry, Nankai University, Tianjin, 300071, China.
Nanoscale. 2020 May 14;12(18):10390-10398. doi: 10.1039/d0nr01837f.
The detection of enzyme activity can provide valuable insights into clinical diagnosis. Herein, we synthesize gold nanobipyramids@MnO2 nanoparticles (AMNS) as the surface-enhanced Raman spectroscopy (SERS) substrate for the first time and design a "turn-on" SERS strategy for the detection of enzyme activity without the need for a complicated SERS nanotag preparation process. In the presence of alkaline phosphatase (ALP), 2-phosphate-l-ascorbic acid trisodium salt (AAP) can be hydrolyzed to ascorbic acid (AA), which can etch the shell of AMNS by reducing MnO2 to Mn2+. The cracked MnO2 shell-caused electromagnetic field enhancement from AMNS can give rise to a significant increase in the Raman intensity of the adsorbed molecules (i.e., crystal violet, CV) on the surfaces of nanobipyramids. Thus, the ALP activity can be accurately quantified based on the MnO2 shell thickness dependent Raman signal output from CV. A linear dynamic range from 0.4 to 20 mU mL-1 with a detection limit of 0.04 mU mL-1 is achieved, which is more sensitive than other spectroscopic methods for ALP detection. Because of its advantages of sensitivity, convenience and versatility, this approach provides a new perspective to disease-related biomolecular detection in the future.
酶活性的检测可以为临床诊断提供有价值的见解。在此，我们首次合成了金纳米双锥@MnO2 纳米粒子（AMNS）作为表面增强拉曼光谱（SERS）基底，并设计了一种无需复杂 SERS 纳米标签制备过程的“开启”SERS 策略来检测酶活性。在碱性磷酸酶（ALP）存在下，2-磷酸-L-抗坏血酸三钠盐（AAP）可以被水解为抗坏血酸（AA），AA 可以通过将 MnO2 还原为 Mn2+来蚀刻 AMNS 的壳。由 AMNS 引起的 MnO2 壳破裂引起的电磁场增强可以导致吸附在纳米双锥表面上的分子（即结晶紫，CV）的拉曼强度显著增加。因此，基于 CV 从 MnO2 壳厚度相关的拉曼信号输出，可以准确地定量 ALP 活性。实现了从 0.4 到 20 mU mL-1 的线性动态范围和 0.04 mU mL-1 的检测限，比其他用于 ALP 检测的光谱方法更灵敏。由于其灵敏度、便利性和多功能性的优势，这种方法为未来与疾病相关的生物分子检测提供了新的视角。
