Shoja Yalda, Rafati Amir Abbas, Ghodsi Javad
Department of Physical Chemistry, Faculty of Chemistry, Bu-Ali Sina University, P.O. Box 65174, Hamedan, Iran.
Department of Physical Chemistry, Faculty of Chemistry, Bu-Ali Sina University, P.O. Box 65174, Hamedan, Iran.
Enzyme Microb Technol. 2017 May;100:20-27. doi: 10.1016/j.enzmictec.2017.02.001. Epub 2017 Feb 2.
Sensing and determination of d-alanine is studied by using an enzymatic biosensor which was constructed on the basis of d-amino acid oxidase (DAAO) immobilization by sol-gel film onto glassy carbon electrode surface modified with nanocomposite of gold nanofilm (Au-NF) and multiwalled carbon nanotubes (MWCNTs). The Au-NF/MWCNT nanocomposite was prepared by applying the potentiostatic technique for electrodeposition of Au-NF on the MWCNT immobilized on glassy carbon electrode surface. The modified electrode is investigated by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), linear sweep voltammetry (LSV) and cyclic voltammetry(CV) techniques. The linear sweep voltammetry was used for determination of d-alanine and the results showed an excellent linear relationship between biosensor response and d-alanine concentration ranging from 0.25μM to 4.5μM with correction coefficient of 0.999 (n=20). Detection limit for the fabricated sensor was calculated about 20nM (for S/N=3) and sensitivity was about 56.1μAμMcm. The developed biosensor exhibited rapid and accurate response to d-alanine, a good stability (4 weeks) and an average recovery of 98.9% in human serum samples.
通过使用一种酶生物传感器来研究D-丙氨酸的传感与测定，该酶生物传感器是基于通过溶胶-凝胶膜将D-氨基酸氧化酶（DAAO）固定在由金纳米膜（Au-NF）和多壁碳纳米管（MWCNT）的纳米复合材料修饰的玻碳电极表面构建而成。通过应用恒电位技术在固定于玻碳电极表面的MWCNT上电沉积Au-NF来制备Au-NF/MWCNT纳米复合材料。通过扫描电子显微镜（SEM）、能量色散X射线光谱（EDX）、线性扫描伏安法（LSV）和循环伏安法（CV）技术研究修饰电极。使用线性扫描伏安法测定D-丙氨酸，结果表明生物传感器响应与D-丙氨酸浓度在0.25μM至4.5μM范围内呈现出良好的线性关系，校正系数为0.999（n = 20）。所制备传感器的检测限计算约为20nM（S/N = 3），灵敏度约为56.1μAμMcm。所开发的生物传感器对D-丙氨酸表现出快速准确的响应、良好的稳定性（4周）以及在人血清样品中的平均回收率为98.9%。
