Department of Biochemistry, M. D. University, Rohtak-124 001, Haryana, India.
Analyst. 2012 Nov 7;137(21):5113-22. doi: 10.1039/c2an35629e. Epub 2012 Sep 18.
The construction of two amperometric l-lysine biosensors is described in this study. The construction comprises the covalent immobilization of lysine oxidase (LOx) onto nanocomposite composed of gold nanoparticles (AuNPs) and carboxylated multiwalled carbon nanotubes (c-MWCNT), decorated on (i) polyaniline (PANI) and (ii) poly 1,2 diaminobenzene (DAB), electrodeposited on Au electrodes. The biosensors were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) and electrochemical impedance spectroscopy (EIS) studies. The optimum response (current) was observed within 2 s at pH 7.0 and 25 °C for LOx/AuNPs/c-MWCNT/PANI/Au, and 4 s at pH 7.0 and 30 °C for LOx/AuNPs/c-MWCNT/DAB/Au electrodes. There was a linear relationship between current and lysine concentration ranging from 5.0 to 600 μM for LOx/AuNPs/c-MWCNT/PANI/Au with a detection limit of 5.0 μM, and 20 to 600 μM for the LOx/AuNPs/c-MWCNT/DAB/Au electrode with a detection limit of 20 μM. The PANI modified electrode was in good agreement with the standard HPLC method, with a better correlation (r = 0.992) compared to the DAB modified electrode (r = 0.986). These observations revealed that the PANI modified Au electrode was better than the DAB modified electrode, and hence it was employed for the determination of lysine in milk, pharmaceutical tablets and sera. The PANI modified electrode showed a half life of 120 days, compared to that of 90 days for the DAB modified electrode, after their 100 uses, when stored at 4 °C.
本研究描述了两种安培型 l-赖氨酸生物传感器的构建。该构建包括赖氨酸氧化酶（LOx）通过共价固定在由金纳米粒子（AuNPs）和羧基化多壁碳纳米管（c-MWCNT）组成的纳米复合材料上，该纳米复合材料修饰在（i）聚苯胺（PANI）和（ii）聚 1,2-二氨基苯（DAB）上，通过电化学沉积在 Au 电极上。通过扫描电子显微镜（SEM）、傅里叶变换红外（FTIR）和电化学阻抗谱（EIS）研究对生物传感器进行了表征。在 pH 7.0 和 25°C 下，对于 LOx/AuNPs/c-MWCNT/PANI/Au 电极，最佳响应（电流）在 2 s 内观察到，而在 pH 7.0 和 30°C 下，对于 LOx/AuNPs/c-MWCNT/DAB/Au 电极，最佳响应（电流）在 4 s 内观察到。对于 LOx/AuNPs/c-MWCNT/PANI/Au 电极，电流与赖氨酸浓度之间存在线性关系，范围为 5.0 至 600 μM，检测限为 5.0 μM，对于 LOx/AuNPs/c-MWCNT/DAB/Au 电极，电流与赖氨酸浓度之间存在线性关系，范围为 20 至 600 μM，检测限为 20 μM。PANI 修饰电极与标准 HPLC 方法非常吻合，与 DAB 修饰电极（r = 0.986）相比，相关性更好（r = 0.992）。这些观察结果表明，PANI 修饰的 Au 电极优于 DAB 修饰的电极，因此它被用于测定牛奶、药片和血清中的赖氨酸。与 DAB 修饰电极（r = 0.986）相比，PANI 修饰电极的相关性更好（r = 0.992）。这些观察结果表明，PANI 修饰的 Au 电极优于 DAB 修饰的电极，因此它被用于测定牛奶、药片和血清中的赖氨酸。与 DAB 修饰电极（r = 0.986）相比，PANI 修饰电极的相关性更好（r = 0.992）。这些观察结果表明，PANI 修饰的 Au 电极优于 DAB 修饰的电极，因此它被用于测定牛奶、药片和血清中的赖氨酸。PANI 修饰电极在 100 次使用后，在 4°C 下储存时，半衰期为 120 天，而 DAB 修饰电极的半衰期为 90 天。
