rapid detection of sars-cov-2 antigen using electrochemical aptasensor based on in-situ two-step preparation of co3(btc)2/spce

Abstract: in global diseases such as sars-cov-2 pandemic, a rapid, accurate, selective, inexpensive, and portable test is needed to diagnostic test at home and preventing the spread of the disease [1, 2]. aptamer-sensors (aptasensors) as novel diagnostic tools have attracted sufficient research interest in biomedical sciences. thus, a label free and ultra-sensitive electrochemical aptasensor for sars-cov-2 spike glycoprotein detection using co3(btc)2 mof, synthesized by in situ growth method, were presented. for this purpose, co-ldh was first synthesized on the disposable screen-printed carbon electrode (spce) surface by electrodeposition method, then, by pouring the h3btc on the surface, the co-ldh became directly co-btc mof [3]. co3(btc)2 as a high-performance surface substrate leads to more loading of aptamer strings, as biological receptor elements, and increases electrochemical sensitivity. the presence of sars-cov-2 spike glycoprotein and the formation of the target-aptamer complex leads to a change in charge transfer resistance (rct) between [fe(cn)6]3–/4– as the redox probe and the electrode surface. the designed aptasensor showed a wide linear sensing range between rct and increasing sars-cov-2 spike glycoprotein concentration in the range of 0.5 fg ml−1 to 1.0 μg ml−1 with a low detection limit of 0.1 fg ml−1 and response time 15 min. in addition, desirable repeatability and reproducibility, selectivity and possibility of application in real samples were found from the provided aptasensor. also, the aptasensor efficiency was evaluated by real samples of sick and healthy individuals and compared with the standard polymerase chain reaction (pcr) method and acceptable results were observed. then, the combination of intrinsic properties of electrochemical technology and the advantages of aptamers can promise promising sensors with fast, sensitive and stable performance.