Influenza A virus-specific aptamers screened by using an integrated microfluidic system.

The influenza A virus is a notorious pathogen that causes high morbidity, high mortality, and even severe global pandemics. Early and rapid diagnosis of the virus is therefore crucial in preventing and controlling any influenza outbreaks. Recently, novel nucleic acid-based affinity reagents called aptamers have emerged as promising candidates for diagnostic assays as they offer several advantages over antibodies, including in vitro selection, chemical synthesis, thermal stability and relatively low costs. Aptamers with high sensitivity and specificity are generated via Systematic Evolution of Ligands by Exponential Enrichment (SELEX), a process that is currently time-consuming, as well as labor- and resource-intensive. In this study, an integrated microfluidic system was developed and was successfully applied to screen a specific aptamer for the influenza A/H1N1 (InfA/H1N1) virus in an automated and highly efficient manner. The selected aptamer was implemented in a magnetic-bead assay, which demonstrated specific and sensitive detection of the InfA/H1N1 virus, even in biological samples such as throat swabs. Consequently, this specific aptamer presents a promising affinity reagent for clinical diagnosis of InfA/H1N1. This is the first demonstration of screening influenza virus-specific aptamers using the microfluidic SELEX technology, which may be expanded for the rapid screening of aptamers against other pathogens for future biomedical applications.