Department of Chemistry, Vivekananda Institute of Technology (East), Jaipur 303 012, India.
Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247 667, India.
Bioelectrochemistry. 2014 Oct;99:24-9. doi: 10.1016/j.bioelechem.2014.06.003. Epub 2014 Jun 15.
An electrochemical study of the oxidation of 8-hydroxyguanine (8-OH-Gua) at gold nanoparticles attached to single walled carbon nanotube modified edge plane pyrolytic graphite electrode (AuNP-SWCNT/EPPGE) has been carried out to develop a method for the self diagnosis of diabetes. The level of 8-OH-Gua, an important biomarker of oxidative DNA damage, is higher in urine of diabetic patients than control subjects. A detailed comparison has been made between the square wave voltammetric (SWV) response of SWCNT/EPPGE and AuNP-SWCNT/EPPGE towards the oxidation of 8-OH-Gua in respect of several essential analytical parameters viz. sensitivity, detection limit, peak current and peak potential. The AuNP-SWCNT/EPPGE exhibited a well defined anodic peak at potential of ~221 mV for the oxidation of 8-OH-Gua as compared to ~312 mV using SWCNT/EPPGE at pH=7.2. Under optimized conditions linear calibration curve for 8-OH-Gua is obtained over a concentration range of 0.01-10.0 nM in phosphate buffer solution (PBS) of pH=7.2 with detection limit and sensitivity of 5.0 (±0.1) pM and 4.9 (±0.1) μA nM(-1), respectively. The oxidation of 8-OH-Gua occurred in a pH dependent process and the electrode reaction followed adsorption controlled pathway. The electrode exhibited an efficient catalytic response with good reproducibility and stability. The method has been found selective and successfully implemented for the determination of 8-OH-Gua in urine samples of diabetic patients.
电化学研究了附着在单壁碳纳米管修饰的边缘平面热解石墨电极（AuNP-SWCNT/EPPGE）上的 8-羟基鸟嘌呤（8-OH-Gua）的氧化，以开发一种用于自我诊断糖尿病的方法。糖尿病患者尿液中的 8-OH-Gua 水平高于对照组，是氧化 DNA 损伤的重要生物标志物。在 pH=7.2 时，对 SWCNT/EPPGE 和 AuNP-SWCNT/EPPGE 对 8-OH-Gua 氧化的方波伏安（SWV）响应进行了详细比较，比较了几个重要的分析参数，如灵敏度、检测限、峰电流和峰电位。与使用 SWCNT/EPPGE 时的312 mV 相比，AuNP-SWCNT/EPPGE 在221 mV 时对 8-OH-Gua 的氧化表现出明确的阳极峰。在优化条件下，在 pH=7.2 的磷酸盐缓冲溶液（PBS）中，8-OH-Gua 的浓度范围为 0.01-10.0 nM 时，可获得线性校准曲线，检测限和灵敏度分别为 5.0（±0.1）pM 和 4.9（±0.1）μA nM(-1)。8-OH-Gua 的氧化是一个依赖于 pH 的过程，电极反应遵循吸附控制途径。该电极表现出高效的催化响应，具有良好的重现性和稳定性。该方法具有选择性，并成功地用于测定糖尿病患者尿液中的 8-OH-Gua。
