IEEE Trans Nanobioscience. 2022 Apr;21(2):265-272. doi: 10.1109/TNB.2021.3118726. Epub 2022 Mar 31.
In this paper, ultra-low level selective detection of bovine serum albumin (BSA) has been demonstrated, based on chemically derived graphene i.e., reduced graphene oxide (RGO) nanosheets. The working principle of the sensor is based upon change in conductance of the RGO nanosheets with different concentration of BSA. The change in conductance is based on the charge transfer between BSA and functional groups of RGO. The morphological and structural characterizations of RGO nanosheets were carried out by scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Raman spectroscopy is performed to further validate the interaction between RGO sensing layer and BSA molecules. Electrical impedance spectroscopy is performed to observe the impedance variation when BSA interacts with RGO. The sensor device exhibits sensitivity of 10 nA/pM. The lower limit of detection (LOD) of the sensor is found to be 1 pM and response time around 35 s, confirming very high sensitivity for BSA. All electrical (current-voltage) measurements were carried out at 2 V bias for low power operation. The sensor exhibits highest sensitivity at 30 °C and for RGO thickness ~4 nm. The RGO based sensor device is selective towards BSA when compared to proteins like L-Histidine, HSA, BHB and Biotin. Our results suggest that RGO based devices are promising for low-cost, portable and real time detection of BSA at room temperature.
本文基于化学衍生的石墨烯，即还原氧化石墨烯（RGO）纳米片，实现了对牛血清白蛋白（BSA）的超低水平选择性检测。传感器的工作原理基于不同浓度 BSA 引起的 RGO 纳米片电导率变化。电导率的变化基于 BSA 和 RGO 官能团之间的电荷转移。通过扫描电子显微镜（SEM）、透射电子显微镜（TEM）、原子力显微镜（AFM）、傅里叶变换红外光谱（FTIR）和 X 射线衍射（XRD）对 RGO 纳米片的形貌和结构进行了表征。拉曼光谱用于进一步验证 RGO 传感层与 BSA 分子之间的相互作用。进行了阻抗谱分析以观察 BSA 与 RGO 相互作用时的阻抗变化。该传感器器件的灵敏度为 10 nA/pM。传感器的检测下限（LOD）为 1 pM，响应时间约为 35 s，证实了对 BSA 非常高的灵敏度。所有电（电流-电压）测量均在 2 V 偏压下进行，以实现低功耗操作。在 30°C 时，RGO 厚度约为 4nm 时，传感器表现出最高的灵敏度。与 L-组氨酸、HSA、BHB 和生物素等蛋白质相比，基于 RGO 的传感器对 BSA 具有更高的选择性。我们的结果表明，基于 RGO 的器件有望用于在室温下低成本、便携式和实时检测 BSA。
