Sequential preconcentration by nanofluidic electrostatic sieving for high sensitive analysis of neurotransmitters released by single cells

[[abstract]]This paper introduces a nanofluidic electrostatic sieving (NES) microdevices incorporating electrochemical sensor with sequential applied electric fields to pre-concentrate scarce neurotransmitters released from single PC-12 cells for continuous detection. The NES device consists of insulating layer coated silicon nanowires (SINWs) array for not only the electrostatic gating of charged molecules but also the sieving of different size molecules. For sequential preconcentration, in every 30 s successively, and the voltage of 10 V was applied at the concentrator after 240s to collect charged biomolecules by the electrostatic repulsion. A detection limit of 30∼75 zeptomoles was achieved, which is close to the levels released by a single neuron in vitro. As a result, the device has potential to improve the detection limit of that requires time-dependent analysis of single-cells