ELectrokinetic traps for integrated biological sample analysis

A new device integrating diverse electrokinetic steps is presented to extract and enrich analytes directly from blood followed by electrophoretic separation. Two sequentially coupled nanojunctions with different pore size formed a trap with selective ion transport properties. The balance between depletion forces near the nanojunctions and/or apparent electromigration can be tuned for analysis of proteins, DNA, or pharmaceuticals. Here, we demonstrate the analysis of ampicillin from blood within 5 min. The obtained linear range of 2.5-20 μg/mL covers the therapeutically relevant concentration for treating sepsis.