Microfluidic in-reservoir pre-concentration using a buffer drain technique

Abstract

Pre-concentration methods are essential for detecting low concentrations of influenza virus in biological samples from patients. Here, we describe a new method for draining buffer from solution in the reservoir of a microfluidic device to increase the concentration of virus in the reservoir. Viruses were captured in the reservoir by an ion depletion barrier from connected ion selective microfluidic channels. 75 mu l of buffer was successfully drained from a 100 mu l sample, resulting in a 4-fold increase in influenza hemagglutinin concentration in the reservoir. The volume of the final concentrated sample was suitable for detection of influenza hemagglutinin by the enzyme-linked immunosorbent assay, demonstrating the usefulness of the developed platform for enhanced sensitivity of virus detection in a conventional analysis.