Pressure-Modulated Selective Electrokinetic Trapping for Direct Enrichment, Purification, and Detection of Nucleic Acids in Human Serum

Micro total analysis systems (μTAS) have been extensively developed for the detection of nucleic acids (NAs) in resource-limited settings in recent years, yet the sample preparation steps that interface real-world samples with on-chip analytics remain as the technical bottleneck. We report pressure-modulated selective electrokinetic trapping (PM-SET) for the direct enrichment, purification, and detection of NAs in human serum in one step without involving the tedious solid phase extraction, chemical amplification, and surface hybridization-based assays. Under appropriately modulated hydrostatic pressures, NAs in human serum were selectively enriched in an electrokinetic concentrator with the majority of background proteins removed, achieving an enrichment factor of >4800 in 15 min. A sequence-specific NA was detected simultaneously during the enrichment process using a complementary morpholino (MO) probe, realizing a limit of detection of 3 pM in 15 min. PM-SET greatly reduces the cost, time, and complexity of sample preparation for NA detection, which could be easily interfaced with existing NA detection devices to achieve true sample-to-answer biomolecular analytics.