State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University , Changsha 410082, PR China.
Anal Chem. 2012 Jan 3;84(1):45-9. doi: 10.1021/ac202895j. Epub 2011 Dec 15.
A novel acetylcholinesterase (AChE) liquid crystal (LC) biosensor based on enzymatic growth of gold nanoparticles (Au NPs) has been developed for amplified detection of acetylcholine (ACh) and AChE inhibitor. In this method, AChE mediates the hydrolysis of acetylthiocholine (ATCl) to form thiocholine, and the latter further reduces AuCl(4)(-) to Au NPs without Au nanoseeds. This process, termed biometallization, leads to a great enhancement in the optical signal of the LC biosensor due to the large size of Au NPs, which can greatly disrupt the orientational arrangement of LCs. On the other hand, the hydrolysis of ATCl is inhibited in the presence of ACh or organophosphate pesticides (OPs, a AChE inhibitor), which will decrease the catalytic growth of Au NPs and, as a result, reduce the orientational response of LCs. On the basis of such an inhibition mechanism, the AChE LC biosensor can be used as an effective way to realize the detection of ACh and AChE inhibitors. The results showed that the AChE LC biosensor was highly sensitive to ACh with a detection limit of 15 μmol/L and OPs with a detection limit of 0.3 nmol/L. This study provides a simple and sensitive AChE LC biosensing approach and offers effective signal enhanced strategies for the development of enzyme LC biosensors.
一种基于金纳米粒子（Au NPs）酶促生长的新型乙酰胆碱酯酶（AChE）液晶（LC）生物传感器已被开发用于放大检测乙酰胆碱（ACh）和 AChE 抑制剂。在这种方法中，AChE 介导乙酰硫代胆碱（ATCl）的水解形成硫代胆碱，后者进一步将 AuCl(4)(-)还原为 Au NPs，而无需 Au 纳米种子。由于 Au NPs 的尺寸较大，这个过程称为生物金属化，导致 LC 生物传感器的光学信号大大增强，因为 Au NPs 可以极大地破坏 LC 的取向排列。另一方面，在存在 ACh 或有机磷农药（OPs，AChE 抑制剂）的情况下，ATCl 的水解被抑制，这将减少 Au NPs 的催化生长，从而降低 LC 的取向响应。基于这种抑制机制，AChE LC 生物传感器可作为一种有效方法来实现对 ACh 和 AChE 抑制剂的检测。结果表明，AChE LC 生物传感器对 ACh 具有高灵敏度，检测限为 15 μmol/L，对 OPs 的检测限为 0.3 nmol/L。本研究提供了一种简单灵敏的 AChE LC 生物传感方法，并为酶 LC 生物传感器的发展提供了有效的信号增强策略。
