Department of Biochemistry, M.D. University, Rohtak 124 001, Haryana, India.
Enzyme Microb Technol. 2013 Apr 10;52(4-5):265-71. doi: 10.1016/j.enzmictec.2013.01.006. Epub 2013 Jan 25.
A commercial lysine oxidase (LyOx) from Trichoderma viride was immobilized covalently onto gold nanoparticles (AuNPs) and platinum nanoparticles (PtNPs) electrodeposited onto Au electrode using 3-aminopropyltriethoxy silane (3-APTES) and glutaraldehyde cross linking chemistry. A lysine biosensor was fabricated using LyOx/3-APTES/AuNPs-PtNPs/Au electrode as a working electrode, Ag/AgCl (3M KCl) as standard electrode and Pt wire as auxiliary electrode connected through a potentiostat. The enzyme electrode was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The cumulative effect of AuNPs and PtNPs showed excellent electrocatalytic activity at low applied potential for detection of H2O2, a product of LyOx reaction. The sensor showed its optimum response within 4s, when polarized at 0.2V vs. Ag/AgCl in 0.1M phosphate buffer, pH 7.5 at 30°C. The linear range and detection limit of the sensor were 1.0-600μM and 1.0μM (S/N=3), respectively. Biosensor measured lysine level in sera, milk and amino acid tablet, which correlated well with those by standard HPLC method. The enzyme electrode lost 50% of its initial activity after 200 uses over a period of 4 months.
一种来自绿色木霉的商业赖氨酸氧化酶（LyOx）通过 3-氨丙基三乙氧基硅烷（3-APTES）和戊二醛交联化学固定在金纳米粒子（AuNPs）和铂纳米粒子（PtNPs）上，这些纳米粒子通过电沉积在 Au 电极上。使用 LyOx/3-APTES/AuNPs-PtNPs/Au 电极作为工作电极、Ag/AgCl（3M KCl）作为标准电极和 Pt 丝作为辅助电极，通过电化学工作站构建了赖氨酸生物传感器。酶电极通过扫描电子显微镜（SEM）、傅里叶变换红外（FTIR）光谱、电化学阻抗谱（EIS）和循环伏安法（CV）进行了表征。AuNPs 和 PtNPs 的累积效应在低施加电位下对 H2O2 的检测表现出优异的电催化活性，H2O2 是 LyOx 反应的产物。该传感器在 30°C 下，于 0.1M 磷酸盐缓冲液、pH 值为 7.5 时，在 0.2V 相对于 Ag/AgCl 偏置下，4s 内达到最佳响应。传感器的线性范围和检测限分别为 1.0-600μM 和 1.0μM（S/N=3）。该生物传感器测量了血清、牛奶和氨基酸片剂中的赖氨酸水平，与标准 HPLC 方法测量的结果相关性良好。酶电极在 4 个月的时间内使用 200 次后，其初始活性损失了 50%。
