QCM Aptasensor for Rapid and Specific Detection of Avian Influenza Virus

There has been a need for rapid detection of Avian Influenza virus (AIV) H5N1 due to it being a potential pandemic threat. Most of the current methods, including culture isolation and PCR, are very sensitive and specific but require specialized laboratories and trained personnel in order to complete the tests and are time-consuming. The goal of this study was to design a biosensor that would be able to rapidly detect AIV H5N1 using aptamers as biosensing material and a quartz crystal microbalance (QCM) for transducing method. Specific DNA aptamers against AIV H5N1 were immobilized, through biotin and streptavidin conjugation, onto the gold surface of QCM sensor to capture the target virus. Magnetic nanobeads (150 nm in diameter) were then added as amplifiers considering its large surface/volume ratio which allows for faster movement and a higher target molecule binding rate. The result showed that the captured AIV caused frequency change, and more change was observed when the AIV concentration increased. The nanobead amplification was effective at the lower concentrations of AIV, however, it was not significant when the AIV concentration was 1 HA or higher. The detection limit of the aptasensor was 1 HAU with a detection time of 1 h. The capture of the target virus on to the surface of QCM sensor and the binding of magnetic nanobeads with the virus was confirmed with electron microscopy. Aptamers have unlimited shelf life and are temperature stable which allows this aptasensor to give much more consistent results specifically for in field applications.