Catunda Lucas Gomes da Silva, Martimiano do Prado Thiago, de Oliveira Tássia Regina, Almeida Dos Santos Daniel Júnior, Gomes Nathalia Oezau, Correa Daniel Souza, Faria Ronaldo Censi, Machado Sérgio Antonio Spinola
Institute of Chemistry of São Carlos, University of São Paulo, São Carlos, SP 13560-970, Brazil.
Nanotechnology National Laboratory for Agriculture (LNNA), Embrapa Instrumentação, São Carlos, SP 13560-970, Brazil.
Electrochim Acta. 2023 May 20;451:142271. doi: 10.1016/j.electacta.2023.142271. Epub 2023 Mar 20.
Fast, sensitive, simple, and cheap sensors are highly desirable to be applied in the health system because they improve point-of-care diagnostics, which can reduce the number of cases of infection or even deaths. In this context, here we report the development of a label-free genosensor using a screen-printed electrode modified with 2D-carbonylated graphitic carbon nitride (CN), poly(diallyldimethylammonium) chloride (PDDA), and glutathione-protected gold nanoparticles (GSH-AuNPs) for photoelectrochemical (PEC) detection of SARS-CoV-2. We also made use of Arduino and 3D printing to miniaturize the sensor device. The electrode surface was characterized by AFM and SEM techniques, and the gold nanoparticles by UV-Vis spectrophotometry. For SARS-CoV-2 detection, capture probe DNA was immobilized on the electrode surface. The hybridization of the final genosensor was tested with a synthetic single-strand DNA target and with natural saliva samples using the photoelectrochemistry method. The device presented a linear range from 1 to 10,000 fmol L and a limit of detection of 2.2 and 3.4 fmol L using cpDNA 1A and 3A respectively. The sensibility and accuracy found for the genosensor using cpDNA 1A using biological samples were 93.3 and 80% respectively, indicating the potential of the label-free and portable genosensor to detect SARS-CoV-2 RNA in saliva samples.
快速、灵敏、简单且廉价的传感器非常适合应用于医疗系统，因为它们能改善即时诊断，从而减少感染病例甚至死亡人数。在此背景下，我们报道了一种无标记基因传感器的研制，该传感器使用了经二维羰基化石墨相氮化碳（CN）、聚二烯丙基二甲基氯化铵（PDDA）和谷胱甘肽保护的金纳米颗粒（GSH-AuNPs）修饰的丝网印刷电极，用于对严重急性呼吸综合征冠状病毒2（SARS-CoV-2）进行光电化学（PEC）检测。我们还利用了Arduino和3D打印技术来实现传感器设备的小型化。通过原子力显微镜（AFM）和扫描电子显微镜（SEM）技术对电极表面进行了表征，并用紫外可见分光光度法对金纳米颗粒进行了表征。对于SARS-CoV-2检测，将捕获探针DNA固定在电极表面。使用光电化学方法，用合成单链DNA靶标和天然唾液样本对最终的基因传感器杂交情况进行了测试。该设备的线性范围为1至10,000 fmol/L，分别使用cpDNA 1A和3A时的检测限为2.2和3.4 fmol/L。使用cpDNA 1A检测生物样本时，基因传感器的灵敏度和准确率分别为93.3%和80%，表明这种无标记便携式基因传感器在检测唾液样本中SARS-CoV-2 RNA方面具有潜力。
