Research progress of biosensors for detection of SARS-CoV-2 variants based on ACE2.

Currently, the coronavirus disease 2019 (COVID-19) pandemic is ravaging the world, causing serious crisis in economy and human health. The top priority is the detection and drug development of the novel coronavirus. The gold standard for real-time diagnosis of coronavirus disease is the reverse transcription-polymerase chain reaction (RT-PCR), which is usually operatively complex and time-consuming. Biosensors are known for their low cost and rapid detection, which are developing rapidly in detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The current study showed that the spike protein of SARS-CoV-2 will bind to angiotensin-converting hormone 2 (ACE2) to mediate the entry of the virus into cells. Interestingly, the affinity between ACE2 and SARS-CoV-2 spike protein increases with the mutation of the virus. Using ACE2 as a biosensor recognition receptor to detect SARS-CoV-2 will effectively avoid the decline of detection accuracy and false negative caused by variants. In fact, due to the variation of the virus, it may even lead to enhanced detection performance. In addition, ACE2-specific drugs to prevent SARS-CoV-2 from entering cells will be effectively evaluated using the biosensors even with virus mutations. Here, we reviewed the biosensors for rapid detection of SARS-CoV-2 by ACE2 and discussed the advantages of ACE2 as an antibody for the detection of SARS-CoV-2 variants. The review also discussed the value of ACE2-based biosensors for screening for drugs that modulate the interaction between ACE2 and SARS-CoV-2.

Recent Advances of Nanomaterials-Based Molecularly Imprinted Electrochemical Sensors.

Molecularly imprinted polymer (MIP) is illustrated as an analogue of a natural biological antibody-antigen system. MIP is an appropriate substrate for electrochemical sensors owing to its binding sites, which match the functional groups and spatial structure of the target analytes. However, the irregular shapes and slow electron transfer rate of MIP limit the sensitivity and conductivity of electrochemical sensors. Nanomaterials, famous for their prominent electron transfer capacity and specific surface area, are increasingly employed in modifications of MIP sensors. Staying ahead of traditional electrochemical sensors, nanomaterials-based MIP sensors represent excellent sensing and recognition capability. This review intends to illustrate their advances over the past five years. Current limitations and development prospects are also discussed.