Nanopore analysis of microfluidically prepared samples using a probe-type lipid bilayer system

Stochastic nanopore sensing using biological nanopores is a powerful technique for detecting and analyzing biological molecules, with promising applications in point-of-care diagnostic systems. However, the need for sample pretreatment before nanopore sensing limits its applicability. Recently, integrated systems combining microfluidic devices and solid-state nanopores have been developed to perform all processes—from sample preparation to sensing—on a single chip. Despite this, integrating such systems with biological nanopores remains challenging owing to the fragility of lipid bilayers, complicating the inclusion of sample pretreatment functions. We developed a nanopore sensing platform capable of detecting microfluidically prepared samples using biological nanopores. DNA samples were mixed using a microfluidic concentration gradient generator (μCGG) that could combine three samples. The mixed samples were then detected using a biological nanopore sensor based on probe-type lipid bilayer systems, where lipid bilayers were formed by inserting microelectrodes into the outlet chambers. We compared the nanopore sensing results of DNA samples prepared with the μCGG to those prepared by pipetting. The scatter plot distributions, along with the number and distribution of peaks in dwell time and current blockage histograms, were highly similar, demonstrating the feasibility of the nanopore sensing platform. This paper presents the first nanopore sensing platform that integrates a microfluidic channel with a sample pretreatment function and a biological nanopore sensor. By combining the high sensitivity of biological nanopore sensors with the high-throughput, low-volume sample preparation of microfluidic devices, this integrated platform has the potential to be a powerful analytical tool for on-chip diagnosis.