(549a) DNA Dynamics in Nanofluidics Under Pulsed Field Electrophoresis

Nanofluidics is the study and application of fluid/particle flow in fluidic conduits at the length scale of nanometers. Due to its small size, nanofluidic devices can handle exceedingly small amount of materials, which provides high resolution for delivering, sensing, and separation of mass-limited samples. When integrated with microchannels as the inlet/outlet, the function of nanofluidic structures can be extended to the system level. Recently, a single-cell nanochannel electroporation (NEP) technique was developed in our laboratory to realize dosage-controlled delivery that could not be achieved by bulk electroporation and microchannel electroporation methods. During the operation of NEP, DNA/RNA transfection agents were electrophoretically transported into individual cells through the nanochannel under electric pulses. The gene delivery mechanism during NEP is governed by the DNA electrophoretic dynamics under pulses. In this study, we carried out Brownian dynamics simulation to investigate the electrophoretic transport of DNA through the nanochannel under electric pulses. The effect of multiple long and short pulses with the same total pulse length is studied in the simulation. Due to the recoiling of DNA chains during the interval between pulses, the transport of DNA under short pulses is not as efficient as that under long pulses. The effect of electric field distribution and DNA conformation on the degree of entrance is analyzed. Multiple-chain dynamics is also studied by simulating multiple chains with intermolecular repulsion. Due to the chain retreatment and the blocking effect, the intermolecular interaction is stronger and the reduction of transportation rate is higher under short pulses. Experimental observations on single DNA dynamics are also implemented in order to verify our simulations.