Ali Md Azahar, Srivastava Saurabh, Agrawal Ved V, Willander Magnus, John Renu, Malhotra Bansi D
Department of Science and Technology Centre on Biomolecular Electronics, Biomedical Instrumentation Section, CSIR-National Physical Laboratory, Dr K. S. Krishnan Marg, New Delhi 110012, India.
J Mater Chem B. 2016 Apr 21;4(15):2706-2714. doi: 10.1039/c5tb02578h. Epub 2016 Apr 4.
A reagent-free, low-cost and sensitive immunosensor has been fabricated using anti-apolipoprotein B (AAB) conjugated l-cysteine in situ capped cadmium sulfide quantum dots (CysCdS QDs) bound to nickel oxide nanorods (nNiO) for detection of low density lipoprotein (LDL) molecules in human serum samples. The structural and morphological properties of AAB conjugated CysCdS QDs and nNiO have been investigated using electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and UV-visible techniques. In this immunosensor, the synthesized NiO nanorods act as mediators that allow the direct electron transfer due to their channeling effect resulting in a mediator-free biosensor. This mediator-free CysCdS-NiO based immunosensor shows improved characteristics such as a good sensitivity of 32.08 μA (mg dl) cm compared to that based on nNiO (1.42 μA (mg dl) cm) alone for detection of lipid (LDL) molecules over a wide concentration range, 5-120 mg dl (0.015-0.36 μM). The kinetic analysis yields an association constant (K) of 3.24 kM s, indicating that the antibody conjugated CysCdS-NiO platform has a strong affinity towards lipid molecules. The excellent electron transport properties of the CysCdS-NiO nanocomposite in this immunosensor reveal that it provides an efficient platform for routine quantification of LDL molecules in real samples.
一种无试剂、低成本且灵敏的免疫传感器已被制备出来，该传感器利用抗载脂蛋白B（AAB）共轭的l-半胱氨酸原位包覆硫化镉量子点（CysCdS QDs）并结合氧化镍纳米棒（nNiO），用于检测人血清样本中的低密度脂蛋白（LDL）分子。已使用电子显微镜、X射线衍射、傅里叶变换红外光谱和紫外可见技术研究了AAB共轭CysCdS QDs和nNiO的结构和形态特性。在这种免疫传感器中，合成的NiO纳米棒充当媒介物，由于其通道效应允许直接电子转移，从而形成无媒介物生物传感器。这种基于无媒介物CysCdS-NiO的免疫传感器显示出改进的特性，例如在5-120 mg dl（0.015-0.36 μM）的宽浓度范围内检测脂质（LDL）分子时，与仅基于nNiO（1.42 μA（mg dl）cm）相比，具有32.08 μA（mg dl）cm的良好灵敏度。动力学分析得出缔合常数（K）为3.24 kM s，表明抗体共轭的CysCdS-NiO平台对脂质分子具有很强的亲和力。这种免疫传感器中CysCdS-NiO纳米复合材料优异的电子传输特性表明，它为实际样品中LDL分子的常规定量提供了一个高效平台。
