Patel Manoj K, Singh Jay, Singh Manish K, Agrawal Ved Varun, Ansari S G, Malhotra B D
National Physical Laboratory (CSIR), Department of Science and Technology, Centre on Biomolecular Electronics, Biomedical Instrumentation Section, Dr. K. S. Krishnan Marg, New Delhi 110012, India.
J Nanosci Nanotechnol. 2013 Mar;13(3):1671-8. doi: 10.1166/jnn.2013.7123.
We report the application of nano crystalline tin oxide quantum dots (SnO2-QDs) for electrochemical detection of Vibrio cholerae based on DNA hybridization technique. SnO2-QDs (- 1-5 nm) have been synthesized by laser ablation technique in liquid (LAL) and electrophoretically deposited onto hydrolyzed surface of indium tin oxide (ITO) coated glass electrode. A single stranded oligonucleotide probe (23 bases) have been designed form the virulent gene sequence of V. cholerae and has been immobilized onto SnO2-QDs/ITO surface for the fabrication of ssDNA/SnO2-QDs/ITO bioelectrode and these bioelectrode have been further used for DNA hybridization (dsDNA/SnO2-QDs/ITO). The electrochemical response studies have been carried out with different concentration genomic DNA (100-500 ng/microL), which indicated that SnO2 provides an effective surface to bind with the phosphate group of DNA, thus resulting in an enhanced electron transport. The hybridized electrode exhibits linear response with regression coefficient (R) 0.974, high sensitivity 35.20 nA/ng/cm2, low detection limit (31.5 ng/microL), faster response time (3 s) and high stability of 0-120 days when stored under refrigerated conditions.
我们报道了基于DNA杂交技术的纳米晶氧化锡量子点（SnO₂-QDs）在霍乱弧菌电化学检测中的应用。通过液体激光烧蚀技术（LAL）合成了SnO₂-QDs（-1-5纳米），并电泳沉积到氧化铟锡（ITO）涂层玻璃电极的水解表面上。从霍乱弧菌的致病基因序列设计了一条单链寡核苷酸探针（23个碱基），并将其固定在SnO₂-QDs/ITO表面，用于制备单链DNA/SnO₂-QDs/ITO生物电极，这些生物电极进一步用于DNA杂交（双链DNA/SnO₂-QDs/ITO）。对不同浓度的基因组DNA（100-500纳克/微升）进行了电化学响应研究，结果表明SnO₂提供了一个与DNA磷酸基团结合的有效表面，从而增强了电子传输。杂交电极呈现线性响应，回归系数（R）为0.974，灵敏度高，为35.20纳安/纳克/平方厘米，检测限低（31.5纳克/微升），响应时间快（3秒），在冷藏条件下储存0-120天具有高稳定性。
