基于酶电极的乳酸检测生物传感器

乳酸(C₃H₆O₃)，又名2-羟基丙酸、丙醇酸，属于羟基酸的一种。乳酸在食品工业、临床医学、生物技术等行业具有极其重要的意义，因此如何高通量检测不同样品中的乳酸成为目前业界研究的重点。传统乳酸检测方法操作繁琐、费时费力或需要昂贵的检测设备，乳酸生物传感器可以克服这些限制，不需要样品制备，能够快速、简便、可靠地定量测定食品或血浆中的乳酸，具有广阔的应用前景。乳酸酶电极生物传感器主要有两种类型——基于L-乳酸氧化酶(L-LOD)和L-乳酸脱氢酶(L-LDH)的乳酸生物传感器。本文综述了L-LOD和L-LDH结构特征、来源及催化机理，讨论了改善基于酶电极的乳酸传感器性能的3种策略(电极材料改造策略、酶固定化策略、酶分子工程改造策略)，还根据用于制造乳酸生物传感器的不同载体包括膜、透明凝胶基质、水凝胶载体、纳米颗粒等对乳酸生物传感器进行了归类分析，最后本文将目前商品化应用的酶电极乳酸生物传感器特点进行了对比总结讨论，阐述了乳酸生物传感器的未来应用方向，并对未来发展前景进行了展望。

Lactic Acid Biosensor Based on Enzyme Electrode

Lactic acid (C₃H₆O₃), also known as 2-hydroxypropionic acid, propanoic acid, is a type of hydroxy acid. It is an essential metabolite of human and microbial cells. In diagnosis and medical management, determination of lactate level in serum is greatly required, and it is also important to measure lactate in fermentative foods to access their quality. Therefore, how to detect lactic acid in different samples with high throughput has become the focus of different researches. The traditional lactic acid detection methods are complicated, time-consuming and laborious, or requires expensive detection equipments. However, the electrochemical enzymatic L-lactate biosensors combining the robustness of electrochemical techniques with the specificity of biological recognition processes showed great advantages over the conventional analytical techniques in size, cost, sensitivity, selectivity, response speed and sample pre-treatment, which show a broad application prospects. There are two main types of lactate biosensors based on L-lactate oxidase (L-LOD) and L-lactate dehydrogenase (L-LDH). Designing a successful enzyme-based L-lactate biosensor requires assembling the enzyme onto a solid carrier and selecting an appropriate transduction strategy between the enzyme and the electrode. Due to the restriction of enzyme molecular structures, reaction mechanism and electrode materials, the traditional lactate biosensors have some limitations in sensitivity, selectivity and stability. Therefore, an increased research was performed to improve the performance of lactate sensors according to the characteristic of the enzymes and the electron transfer type. In this paper, we provide an overview of the structural characteristics, origin and catalytic mechanism of L-LOD and L-LDH, and discuss three strategies, including electrode material modification, enzyme immobilization and enzyme engineering modification, to improve the performance of enzyme electrode based lactate biosensors. In addition, the lactate biosensors were compared and analyzed on the basis of different carriers including membrane, transparent gel matrix, hydrogel carrier, nano-particles, etc. Finally, we comprehensively described the merits and demerits of current commercial lactate sensors and preconceive how emerging new technologies may benefit to future lactate biosensor design.