Amity Center of Nanotechnology, Amity University, Haryana, 122413, India; Department of Biotechnology Engineering and Food Technology, Chandigarh University, Mohali, 140413, India.
Department of Medical Biotechnology, Gujarat Biotechnology University (GBU), Gujarat International Finance and Tec (GIFT) City. Gandhinagar, Gujarat, 382355, India.
Chemosphere. 2022 Aug;300:134428. doi: 10.1016/j.chemosphere.2022.134428. Epub 2022 Apr 5.
The graphene quantum dots (GQDs) was synthesized using potato starch and water by hydrothermal method and further used for reduction of tetracholoroauric acid to form graphene quantum dots-gold (GQDs@AuNPs) nanocomposite. The GQDs/GQDs@AuNPs were analyzed using FTIR, UV-Vis, Flourometry and HR-TEM. The synthesized GQDs@AuNPs were further used for fabrication of cost-effective screen-printed paper electrode (SPPE) based DNA sensor for the detection of O. tsutsugamushi using htrA gene specific 5'NH2 linked DNA probe. Modification of SPPE using GQDs@AuNPs nanocomposite and ssDNA probe was monitored using EIS, FTIR, FE-SEM and AFM. The sensor detection limit (LOD) was assessed as 0.002 ng/μl from the standard calibration curve with the correlation coefficient, R = 0.993. The sensitivity of the DNA sensor was calculated as 7700 μA/cm/ng for ssGDNA of O. tsutsugamushi using cyclic voltammetry. The sensor validation was done using scrub typhus patient's blood DNA samples. The sensor showed good storage stability at 4 °C for six months with just a loss of 12% of the initial current values. The SPPE/DNA sensor developed is very specific, sensitive, stable and detects O. tsutsugamushi in less time.
采用水热法以马铃薯淀粉和水为原料合成了石墨烯量子点（GQDs），并进一步将其用于还原四氯金酸，形成石墨烯量子点-金（GQDs@AuNPs）纳米复合材料。通过傅里叶变换红外光谱（FTIR）、紫外-可见光谱（UV-Vis）、荧光光谱和高分辨率透射电子显微镜（HR-TEM）对 GQDs 和 GQDs@AuNPs 进行了分析。进一步将合成的 GQDs@AuNPs 用于制备基于成本效益的丝网印刷纸电极（SPPE）的 DNA 传感器，用于检测恙虫病东方体（O. tsutsugamushi）的 htrA 基因特异性 5'NH2 连接的 DNA 探针。使用 GQDs@AuNPs 纳米复合材料和 ssDNA 探针修饰 SPPE 后，通过电化学阻抗谱（EIS）、傅里叶变换红外光谱（FTIR）、场发射扫描电子显微镜（FE-SEM）和原子力显微镜（AFM）进行了监测。通过标准校准曲线评估传感器的检测限（LOD）为 0.002ng/μl，相关系数 R 为 0.993。使用循环伏安法，计算出 O. tsutsugamushi 的 ssGDNA 的 DNA 传感器的灵敏度为 7700μA/cm/ng。使用恙虫病患者的血液 DNA 样本对传感器进行了验证。传感器在 4°C 下储存 6 个月稳定性良好，仅损失初始电流值的 12%。开发的 SPPE/DNA 传感器具有特异性强、灵敏度高、稳定性好的特点，并且能够在更短的时间内检测到恙虫病东方体。
