【Huazhong Agricultural University: Development of portable immune sensors for the identification of porcine epidemic diarrhea virus】

1. Background

This study developed and validated a portable immunosensor based on floating gate carbon nanotube field-effect transistor (FG CNT-FET) for rapid, sensitive, and accurate identification of PEDV.

Porcine Epidemic Diarrhea (PED) is an acute and highly contagious intestinal infectious disease caused by Porcine Epidemic Diarrhea Virus (PEDV), mainly causing watery diarrhea, vomiting, dehydration, and even death in piglets. In 1977, PEDV was first discovered in Belgium,The virus was wildly prevalent in China at the end of 2010. Its incidence rate was almost 100%, and the mortality rate was as high as 50%~90%, which caused disastrous economic losses to the pig industry in China. Therefore, in order to effectively block the spread of PEDV and prevent the occurrence of major epidemics, it is crucial to develop and establish fast and effective detection methods.

2. Research content

Field effect transistor (FET) is a biosensing platform with excellent sensitivity, label free and real-time detection, low cost, and easy integration. Currently, FET based biosensors are increasingly being used for the detection of various biomarkers.Among various nanomaterials, carbon nanotubes (CNTs) are ideal channel materials for FET biosensors due to their ultra-thin thickness, excellent electrical properties, and good biocompatibility. In previous research, a plug and play floating gate CNT field-effect transistor (FG CNT-FET) biochip has been constructed, integrating an intelligent portable reader.It is combined with the improved CRISPR/Cas12a system and introduces a G-triple stranded reporter gene, achieving ultra sensitive and real-time detection of cardiac troponin I, demonstrating good application prospects.On this basis, this study utilized the high affinity of antigen antibodies to prepare and purify monoclonal antibodies that can specifically bind to PEDV-S protein. Then, the antibodies were further functionalized using FG CNT-FET chips to create an immunosensor FG CNT-FET for detecting PEDV virus particles.

Due to the high affinity of antigen-antibody and the high κ-dielectric layer technology of FG CNT-FET, the developed biosensor has high sensitivity and specificity. The immunosensor can detect PEDV and porcine Delta Coronavirus (PDCoV) in less than 1 minute.Meanwhile, the detection thresholds for PEDV-S protein and PEDV virions can be as low as 8.1fg /mL (recombinant PEDV-S protein) and 100.14TCID50 /mL (PEDV virions), respectively, which are the lowest values achieved by PEDV antigen detection methods reported so far.in addition, because the sensor is small and portable, it can be used as a chip reader deployed in the field to achieve rapid and effective detection of PEDV in the way of "sample in-answer out", which provides the possibility for further large-scale on-site monitoring of infectious diseases on farms.

Source: Sensor Expert Network