A Portable Impedance Biosensing System for Rapid Detection of Avian Influenza Virus

Abstract. Avian influenza virus (AIV) H5N1 is a highly infectious pathogen that can be dangerous to both poultry and humans. A rapid and sensitive detection method is needed to help prevent the spread of AIV H5N1. In this study, a portable impedance biosensing system was designed to integrate a laptop computer with LabVIEW software, a data acquisition (DAQ) device, a sample delivery system, a micro-flow cell, and a gold interdigitated microelectrode (IDME) into an automatic instrument for rapid detection of AIV H5N1. Streptavidin was first immobilized onto the IDME surface, and then biotin-labeled H5N1-specific aptamer was immobilized on the IDME surface through streptavidin and biotin binding. Samples were delivered through the sample delivery system into the micro-flow cell, and AIV H5N1 was captured by the aptamer on the IDME, resulting in a change in the impedance. A virtual instrument (VI) was programmed with LabVIEW software to provide a platform for sample delivery, impedance measurement, data processing, and control. The audio card of the laptop was used as a function generator, while the DAQ device was used for data communication. The impedance measured by this biosensing system was compared with that measured by a BAS IM6 impedance analyzer, and the error was less than 5%. The results indicated that the developed system could detect AIV H5N1 at a detection limit of 0.84 HAU per 200 I¼L without interaction with three non-target AIV subtypes (H1N1, H5N2, and H5N3). The system was portable and automatic, and it showed great potential as a diagnostic and epidemiological tool for detection of AIV in the field.