Streaming potential sensing in paper-based microfluidic channels

Streaming potential measurements detected the presence of adsorbed polyvinylamine or potassium polyvinylsulfate in paper-based microfluidic devices. Capillary driven flow in filter paper induced measurable potentials in the range −80 to +80 mV. The magnitude and polarity of the measured potentials were sensitive to the presence of adsorbed polymer. In a second example, paper treated with BSA gave a positive streaming potential at pH 3.7, below the isoelectric point of BSA, and a negative potential at high pH. We propose that streaming potential may provide an electronic interface for paper-based biosensors.