Nanofluidic sensing at normal physiological condition by coupling ion concentration polarization with a limit of detection of one femtomole

Traditional nanofluidic devices lose function at normal physiological condition (e.g. 0.1 M), because the thickness of electrical-double-layer (EDL) λ_D (~1 nm) under this circumstance is much smaller than typical nanochannel size, which significantly limits their clinical applications. This work enables nanofluidic sensing of Biotin at normal physiological condition by coupling ion concentration polarization (ICP) with nanofluidic crystal (NFC), which utilizes the enrichment effect for target preconcentration and the depletion effect for buffer desalination, with a limit of detection of 1 fM.