Du Fusheng, Zheng Kai, Zeng Shuwen, Yuan Yufeng
School of Electronic Engineering and Intelligentization, Dongguan University of Technology, Dongguan, 523808, China.
School of Civil Aviation, Northwestern Polytechnical University, Xi'an, Shanxi, 710072, China.
Nanophotonics. 2023 Mar 7;12(7):1271-1284. doi: 10.1515/nanoph-2022-0798. eCollection 2023 Apr.
This study theoretically demonstrated an insight for designing a novel tunable plasmonic biosensor, which was created by simply stacking a twisted bilayer graphene (TBG) superlattice onto a plasmonic gold thin film. To achieve ultrasensitive biosensing, the plasmonic biosensor was modulated by Goos-Hänchen (GH) shift. Interestingly, our proposed biosensor exhibited tunable biosensing ability, largely depending on the twisted angle. When the relative twisted angle was optimized to be 55.3°, such a configuration: 44 nm Au film/1-TBG superlattice could produce an ultralow reflectivity of 2.2038 × 10 and ultra-large GH shift of 4.4785 × 10 µm. For a small refractive index (RI) increment of 0.0012 RIU (refractive index unit) in sensing interface, the optimal configuration could offer an ultra-high GH shift detection sensitivity of 3.9570 × 10 µm/RIU. More importantly, the optimal plasmonic configuration demonstrated a theoretical possibility of quantitatively monitoring severe acute respiratory syndrome coronavirus (SARS-CoV-2) and human hemoglobin. Considering an extremely small RI change as little as 3 × 10 RIU, a good linear response between detection concentration of SARS-CoV-2 and changes in differential GH shift was studied. For SARS-CoV-2, a linear detection interval was obtained from 0 to 2 nM. For human hemoglobin, a linear detection range was achieved from 0 to 0.002 g/L. Our work will be important to develop novel TBG-enhanced biosensors for quantitatively detecting microorganisms and biomolecules in biomedical application.
本研究从理论上展示了一种设计新型可调谐等离子体生物传感器的思路，该传感器是通过将扭曲双层石墨烯（TBG）超晶格简单堆叠在等离子体金薄膜上制成的。为了实现超灵敏生物传感，该等离子体生物传感器由古斯-汉欣（GH）位移调制。有趣的是，我们提出的生物传感器表现出可调谐的生物传感能力，这在很大程度上取决于扭曲角度。当相对扭曲角度优化为55.3°时，这样的结构：44纳米金膜/1-TBG超晶格可产生2.2038×10的超低反射率和4.4785×10微米的超大GH位移。对于传感界面中0.0012 RIU（折射率单位）的小折射率（RI）增量，最佳配置可提供3.9570×10微米/RIU的超高GH位移检测灵敏度。更重要的是，最佳等离子体配置展示了定量监测严重急性呼吸综合征冠状病毒（SARS-CoV-2）和人类血红蛋白的理论可能性。考虑到低至3×10 RIU的极小RI变化，研究了SARS-CoV-2检测浓度与差分GH位移变化之间的良好线性响应。对于SARS-CoV-2，获得了0至2 nM的线性检测区间。对于人类血红蛋白，实现了0至0.002 g/L的线性检测范围。我们的工作对于开发用于生物医学应用中定量检测微生物和生物分子的新型TBG增强生物传感器具有重要意义。
