The Institute of NBC Defense PLA Army, Beijing 102205, China.
Unit No. 32169 of PLA, Nyingchi 860000, China.
Sensors (Basel). 2023 Jun 22;23(13):5820. doi: 10.3390/s23135820.
Protective antigen (PA) is an important biomarker for the early diagnosis of anthrax, and the accurate detection of protective antigen under extremely low concentration conditions has always been a hot topic in the biomedical field. To complete the diagnosis of anthrax in a timely manner, it is necessary to detect PA at extremely low concentrations, as the amount of PA produced in the early stage of anthrax invasion is relatively small. Graphene field-effect transistor (Gr-FET) biosensors are a new type of material for preparing biosensors, with the advantages of a short detection time and ultra-low detection limit.
The effect of different concentrations of diluents on the affinity of PA monoclonal antibodies was determined via an ELISA experiment. Combined with the Debye equation, 0.01 × PBS solution was finally selected as the diluent for the experiment. Then, a PA monoclonal antibody was selected as the bio-recognition element to construct a Gr-FET device based on CVD-grown graphene, which was used to detect the concentration of PA while recording the response time, linear range, detection limit, and other parameters.
The experimental results showed that the biosensor could quickly detect PA, with a linear range of 10 fg/mL to 100 pg/mL and a detection limit of 10 fg/mL. In addition, the biosensor showed excellent specificity and repeatability.
By constructing a Gr-FET device based on CVD-grown graphene and selecting a PA monoclonal antibody as the bio-recognition element, a highly sensitive, specific, and repeatable Gr-FET biosensor was successfully prepared for detecting extremely low concentrations of anthrax protective antigen (PA). This biosensor is expected to have a wide range of applications in clinical medicine and biological safety monitoring.
保护性抗原（PA）是炭疽病早期诊断的重要生物标志物，在极低浓度条件下准确检测保护性抗原一直是生物医学领域的热点。为了及时完成炭疽病的诊断，有必要在极低浓度下检测 PA，因为炭疽病入侵早期产生的 PA 量相对较少。石墨烯场效应晶体管（Gr-FET）生物传感器是一种新型的生物传感器制备材料，具有检测时间短、检测极限超低的优点。
通过 ELISA 实验确定不同浓度稀释剂对 PA 单克隆抗体亲和力的影响。结合德拜方程，最终选择 0.01×PBS 溶液作为实验的稀释剂。然后，选择 PA 单克隆抗体作为生物识别元件，基于 CVD 生长的石墨烯构建 Gr-FET 器件，用于检测 PA 的浓度，同时记录响应时间、线性范围、检测限等参数。
实验结果表明，该生物传感器能够快速检测 PA，线性范围为 10 fg/mL 至 100 pg/mL，检测限为 10 fg/mL。此外，该生物传感器表现出优异的特异性和重复性。
通过构建基于 CVD 生长石墨烯的 Gr-FET 器件，并选择 PA 单克隆抗体作为生物识别元件，成功制备了用于检测极低浓度炭疽保护性抗原（PA）的高灵敏度、高特异性和高重复性的 Gr-FET 生物传感器。该生物传感器有望在临床医学和生物安全监测等领域得到广泛应用。
