Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, Hubei Province, PR China.
Biosens Bioelectron. 2010 Feb 15;25(6):1370-5. doi: 10.1016/j.bios.2009.10.032. Epub 2009 Oct 30.
An amperometric biosensor for highly selective and sensitive determination of methyl parathion (MP) was developed based on dual-signal amplification: (1) a large amount of introduced enzyme on the electrode surface and (2) synergistic effects of nanoparticles towards enzymatic catalysis. The fabrication process includes (1) electrochemical deposition of gold nanoparticles by a multi-potential step technique at multiwalled carbon nanotube (MWCNT) film pre-cast on a glassy carbon electrode and (2) immobilization of methyl parathion degrading enzyme (MPDE) onto a modified electrode through CdTe quantum dots (CdTe QDs) covalent attachment. The introduced MWCNT and gold nanoparticles significantly increased the surface area and exhibited synergistic effects towards enzymatic catalysis. CdTe QDs are further used as carriers to load a large amount of enzyme. As a result of these two important enhancement factors, the proposed biosensor exhibited extremely sensitive, perfectly selective, and rapid response to methyl parathion in the absence of a mediator. The detection limit was 1.0 ng/mL. Moreover, since MPDE hydrolyzes pesticides containing the P-S bond, it showed high selectivity for detecting MP and many interfering compounds, such as carbamate pesticides. Other organophosphorous pesticides and oxygen-containing inorganic ions (SO(4)(2-), NO(3)(-)) did not interfere with the determination. The proposed MPDE biosensor presents good reproducibility and stability, and the MPDE is not poisoned by organophosphate pesticides. Unlike cholinesterase-based biosensor, the MPDE biosensor can be potentially reused and is suitable for continuous monitoring.
基于双重信号放大作用，研制出一种用于高度选择性和灵敏测定甲基对硫磷（MP）的安培生物传感器：（1）在多壁碳纳米管（MWCNT）预先涂覆在玻碳电极上的薄膜上，通过多电位阶跃技术电化学沉积大量酶；（2）通过 CdTe 量子点（CdTe QDs）共价附着将甲基对硫磷降解酶（MPDE）固定在修饰电极上。引入的 MWCNT 和金纳米粒子显著增加了酶的表面面积，并对酶的催化表现出协同作用。CdTe QDs 进一步用作载体以负载大量酶。由于这两个重要的增强因子，与使用媒介体的情况相比，所提出的生物传感器对甲基对硫磷表现出极其灵敏、完美的选择性和快速的响应。检测限为 1.0ng/mL。此外，由于 MPDE 可水解含有 P-S 键的农药，因此它对检测 MP 和许多干扰化合物（如氨基甲酸酯类农药）表现出高选择性。其他有机磷农药和含氧无机离子（SO(4)(2-), NO(3)(-))不会干扰测定。所提出的 MPDE 生物传感器具有良好的重现性和稳定性，且 MPDE 不会被有机磷农药毒害。与基于胆碱酯酶的生物传感器不同，MPDE 生物传感器可潜在地重复使用，适用于连续监测。
