Semiconductor Based Biosensors for Bacterial Pathogens

Chan-En Chien (簡湛恩), Wei-Lun Wang, Yuh-Shyong Yang*

Department of Biological Science and Technology, National Yang Ming Chiao Tung University 

   Bacterial pathogen detection is critical in various fields, such as food products and water sources contamination results in severe consequences. Mainly, the widespread of Escherichia coli and Salmonella causes severe illness to mankind, especially drug-resistant Staphylococcus aureus (MRSA) is a life-threatened issue. Acidovorax avenue subsp. citrulli (Aac) is a pathogen of cucurbitaceous plants that can cause huge economic losses. Current bacterial detection methods involve bacteria isolation culture and biochemical tests, which are time-consuming. Although enzyme-linked immunosorbent assay (ELISA) detection is relatively fast, but it is high cost and requires trained personnel to perform the tests. Our lab has developed two label-free semiconductor-based bacterial detection platforms, which are extended gate field-effect transistor (EGFET) and poly-silicon nanowire field-effect transistor (pSiNWFET) biosensor. We demonstrated the development of these two semiconductor-based biosensors for bacterial sensing. The results indicate that the detection limit can reach 10 CFU/mL. The biosensors have the advantages of high sensitivity, label-free, real-time sensing at a relatively low cost that could satisfy the current unmet needs for bacterial detection. In addition to electrical measurement, we also combine the technique of scanning the biochip surface topography using an Atomic Force Microscope (AFM). The morphology of different target bacteria, such as rod-shaped or spherical-shaped, can be distinguished by using AFM. We expect this approach to become a powerful technique to validate the specificity of bacterial biosensors in biomedical research and food industries.