Microfluidic paper-based sample preconcentrator by ION concentration polarization

Microfluidic paper-based analytical devices (μPAD) for molecule preconcentrator have critical problem in non-specific binding and dispersion of the collected molecules, so there is a limitation to the use of direct body fluid (i.e. serum). To address this problem, we demonstrate molecule preconcentration on paper-based reservoir preconcentrator by ion concentration polarization (ICP) with minimal addition on paper-based reservoir using an undiluted human serum. The cation selective membrane (i.e., Nafion) is patterned on adhesive tape, and this tape is punching to create sample reservoir and buffer reservoir, and then attached to paper-based reservoir. When an electric field is applied across the Nafion, ICP is initiated to preconcentrate the molecules in the sample paper-based reservoir. As a result, fluorescent dyes (alexa fluor 488) in undiluted human serum sample are preconcentrated up to 5-fold. This result is a major advance in molecule preconcentration using an undiluted body fluid for the growing field of POC diagnostics.