A simple electrokinetic protein preconcentrator utilizing nano-interstices.

This work proposes a simple method for creating nanofluidic channels for protein preconcentration through self-assembled gold nanoparticles (AuNPs) using the exclusion-enrichment effect. A depletion force is elicited in nano-interstices among self-assembled AuNPs due to the overlap of electrical double layers (EDLs); therefore, proteins quickly accumulate. The experimental results show that the generation of depletion forces is correlated with the size of the AuNPs. The self-assembled monolayer of AuNPs (13 nm in diameter) can successfully preconcentrate proteins through effective EDL overlapping. This approach provides a new process to produce nanochannels that does not require high-voltage or time-consuming fabrication.