Flow Behavior Characterization of DNA Molecules in Passive Nanofluidic Devices†

This work aims to develop a method for analyzing the dynamic flow of single DNA molecules through nanochannels in fluidic chip which work passively. For this purpose, a two-laser system was used, which is coupled into a fluorescence microscope and can detect labeled DNA molecules using a single photon counter for signal read-out in real-time. The two laser spots are focused at different points of the nanochannel, and can be used to obtain the speed and molecular extension of the DNA. For example, a velocity of 1.82 μm/ms and a spatial extension of 0.9 μm were determined for pUC18/19 DNA (2686 bp) in a nanochannel with a width and depth of 200 nm × 100 nm and a length of 10 μm.