Woo Sung Oh, Froberg James, Pan Yanxiong, Tani Sakurako, Goldsmith Brett R, Yang Zhongyu, Choi Yongki
Department of Physics, North Dakota State University, Fargo, North Dakota 58108, USA.
Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108, USA.
ACS Appl Electron Mater. 2020 Apr 28;2(4):913-919. doi: 10.1021/acsaelm.9b00840. Epub 2020 Mar 9.
Although graphene-based biosensors provid extreme sensitivity for the detection of atoms, gases, and biomolecules, the specificity of graphene biosensors to the target molecules requires surface decoration of graphene with bifunctional linkers such pyrene derivatives. Here, we demonstrate that the pyrene functionalization influences graphene's electrical properties by yielding partial formation of bilayer graphene which was confirmed by Raman 2D spectrum. Based on this observation, we introduce quadratic fit analysis of the nonlinear electrical behavior of pyrene-functionalized graphene near the Dirac point. Compared to the conventional linear fit analysis of the transconductance at a distance from the Dirac point, the quadratic fit analysis of the nonlinear transconductance near the Dirac point increased the overall protein detection sensitivity by a factor of 5. Furthermore, we show that both pyrene linkers and gating voltage near the Dirac point play critical roles in sensitive and reliable detection of proteins' biological activities with the graphene biosensors.
尽管基于石墨烯的生物传感器在检测原子、气体和生物分子方面具有极高的灵敏度，但石墨烯生物传感器对目标分子的特异性需要用芘衍生物等双功能连接体对石墨烯进行表面修饰。在此，我们证明芘功能化通过产生部分双层石墨烯的形成来影响石墨烯的电学性质，这一点通过拉曼2D光谱得到了证实。基于这一观察结果，我们引入了对狄拉克点附近芘功能化石墨烯的非线性电学行为的二次拟合分析。与在远离狄拉克点处对跨导进行的传统线性拟合分析相比，狄拉克点附近非线性跨导的二次拟合分析将整体蛋白质检测灵敏度提高了5倍。此外，我们表明芘连接体和狄拉克点附近的门控电压在利用石墨烯生物传感器灵敏且可靠地检测蛋白质生物活性方面都起着关键作用。
