Abstract：
Early and reliable detection of an infectious viral disease is critical to accurately monitor outbreaks and to provide individuals and health care professionals the opportunity to treat patients at the early stages of a disease. The accuracy of such information is essential to define appropriate actions to protect the population and to reduce the likelihood of a possible pandemic. Here, we show the fabrication of freestanding laser-induced graphene (FLIG) flakes that are highly sensitive sensors for high-fidelity viral detection. As a case study, we show the detection of SARS-CoV-2 spike proteins. FLIG flakes are nonembedded porous graphene foams ca. 30 μm thick that are generated using laser irradiation of polyimide and can be fabricated in seconds at a low cost. Larger pieces of FLIG were cut forming a cantilever, used as suspended resonators, and characterized for their electromechanics behavior. Thermomechanical analysis showed FLIG stiffness comparable to other porous materials such as boron nitride foam, and electrostatic excitation showed amplification of the vibrations at frequencies in the range of several kilo-hertz. We developed a protocol for aqueous biological sensing by characterizing the wetting dynamic response of the sensor in buffer solution and in water, and devices functionalized with COVID-19 antibodies specifically detected SARS-CoV-2 spike protein binding, while not detecting other viruses such as MS2. The FLIG sensors showed a clear mass-dependent frequency response shift of ∼1 Hz/pg, and low nanomolar concentrations could be detected. Ultimately, the sensors demonstrated an outstanding limit of detection of 2.63 pg, which is equivalent to as few as ∼5000 SARS-CoV-2 viruses. Thus, the FLIG platform technology can be utilized to develop portable and highly accurate sensors, including biological applications where the fast and reliable protein or infectious particle detection is critical.
摘要：
早期和可靠地检测传染性病毒性疾病对于准确监测暴发和为个人和卫生保健专业人员提供在疾病早期阶段治疗患者的机会至关重要。这些信息的准确性对于确定保护人口和减少可能的大流行可能性的适当行动至关重要。这里,我们展示了独立式激光诱导石墨烯（FLIG）薄片的制造，这些薄片是用于高保真病毒检测的高灵敏度传感器。作为一个案例研究，我们显示了SARS-CoV-2刺突蛋白的检测。FLIG薄片是非嵌入的多孔石墨烯泡沫。使用聚酰亚胺的激光照射产生的30μm厚,并且可以以低成本在几秒钟内制造。切割较大的FLIG片，形成悬臂，用作悬浮谐振器，并以其机电行为为特征。热机械分析显示FLIG刚度可与其他多孔材料相媲美，如氮化硼泡沫，静电激发显示振动在几千赫兹的频率范围内放大。我们通过表征传感器在缓冲溶液和水中的润湿动态响应，开发了用于水性生物传感的协议。和用COVID-19抗体功能化的装置特异性检测到SARS-CoV-2刺突蛋白结合，而不检测其他病毒，如MS2。FLIG传感器显示出明显的质量相关频率响应偏移，为~1Hz/pg，并且可以检测到低纳摩尔浓度。最终,传感器表现出2.63pg的突出检测极限，相当于5000种SARS-CoV-2病毒。因此，FLIG平台技术可用于开发便携式和高精度传感器，包括快速可靠的蛋白质或感染性颗粒检测至关重要的生物应用。
