Direct-write femtosecond laser ablation and DNA combing and imprinting for fabrication of a nanofluidic device on ethylene glycol dimethacrylate polymer

It is necessary to have ordered lateral nanochannels to manipulate liquids, ions and biomolecules at extremely high levels of spatial confinement for nanofluidics, molecular separation, and DNA/gene delivery applications. Using DNA Combing and Imprinting (DCI) technique, well ordered arrays of microwells connected by nanoscale channels with sizes on the order of 10 nm can be created in ethylene glycol dimethacrylate (EGMDA) polymer. Still larger microscale channels which lead into the arrays are needed to allow the arrays of microwells and nanochannels to be externally filled with desired reagents, molecules, cells. In the present work, direct-femtosecond laser ablation was employed as post process to fabricate these microscale filling channels. Single pulse and multiple pulses overlap ablations were first conducted on EGMDA polymer using focused femtosecond laser beam. Scanning electron microscopy (SEM) was employed to measure ablated channel width. Single pulse ablation threshold fluence and incubation coefficient were found and were used to predict microchannel width. Finally, femtosecond laser ablation was used to fabricate filling channels on microwell/nanochannel arrays. Fluorescent flow test was performed on the microchannels and nanochannels to verify connectivity between the laser-ablated filling channels and the microwell/nanochannel arrays.