Develop a Portable Multiplexed EG-FET Reader for On-Site Bio Detection 

許凱茵,林秀芳,歐陽均兒,楊淑君,趙亦祿,楊裕雄 

Institute of Molecular Medicine and Bioengineering, 

National Yang Ming Chiao Tung University 

Porcine Epidemic Diarrhea Virus and Porcine Deltacoronavirus pose significant challenges,  causing severe intestinal infections, high mortality rates, and substantial economic losses in swine  industry. These viruses spread rapidly, leading to cross-infections. Although current diagnostic  methods offer high sensitivity, they require specialized personnel, expensive equipment, and  lengthy processing times, limiting their real-time, on-site monitoring feasibility. Therefore, a  portable, rapid, and sensitive multi-pathogen detection system with minimal sample preparation is  essential for effective disease surveillance and biosecurity management. This study develops a  portable biosensor integrating an Extended Gate Field-Effect Transistor (EGFET) biochip with a  Raspberry Pi platform, enabling simultaneous detection of multiple biological markers for  real-time nucleic acid analysis. This study was divided into three parts: (i) In hardware design,  resistor and capacitor parameters were optimized and validated using an oscilloscope to ensure  circuit stability and measurement accuracy. Temperature testing was conducted to assess system  stability under different environmental conditions. (ii) In software development, implemented in  Python, measurement functions and an optimized human-machine interface for improved  usability were included. A precision Source Measurement Unit (SMU) was also used to validate  the same biochip and confirm that the portable reader's performance has a similar precision as that  of the SMU. (iii) The biosensing part includes using specific probes to determine synthetic  sequences, cDNA, and crude extracted samples. These results demonstrated that portable readers  and biochips have high sensitivity, specificity, and multi-pathogen detection capabilities. This study successfully developed a prototype of a portable multi-EGFET biosensor reader, offering an inexpensive, highly sensitive, user-friendly, and stable on-site livestock disease detection. In the  future, this system can integrate more functions and potentially advance point-of-care testing technology, improve disease prevention efficiency, and minimize economic losses. 

Keywords: Portable biosensor, EGFET, MCU, Raspberry Pi, Nucleic acid detection