3-D biomimetic micro-channel network by laser direct writing

Nanosecond and femtosecond near IR laser direct write is a useful tool for fabricating 3D, multiple-level microfluidic structures. Using a diode-pumped nanosecond fundamental Nd:YAG laser, multi-depth, multi-width microstructures on silicon were fabricated without lithography-based technology. The molten material inside the microchannel was ejected by a modified assist gas and thus the amount of laser ablation was increased. The solidified molten material and the debris build-up due to the strong thermal reaction of silicon to the nanosecond IR laser pulse was cleaned up with chemical wet etching in HF and HNO3 solution. Micromachining experiments were also done using a femtosecond fiber laser. Microchannels ranging from 2-20¼m could be fabricated using the femtosecond laser. The usefulness of laser micromachining was demonstrated by realizing a semicircular cross-sectional microchannel, which is difficult to accomplish with the lithography-based technology. Rapid prototyping of an artificial vascular network having variable depth and width was carried out and a fluid flow in the PDMS replica of the network was visualized.Nanosecond and femtosecond near IR laser direct write is a useful tool for fabricating 3D, multiple-level microfluidic structures. Using a diode-pumped nanosecond fundamental Nd:YAG laser, multi-depth, multi-width microstructures on silicon were fabricated without lithography-based technology. The molten material inside the microchannel was ejected by a modified assist gas and thus the amount of laser ablation was increased. The solidified molten material and the debris build-up due to the strong thermal reaction of silicon to the nanosecond IR laser pulse was cleaned up with chemical wet etching in HF and HNO3 solution. Micromachining experiments were also done using a femtosecond fiber laser. Microchannels ranging from 2-20¼m could be fabricated using the femtosecond laser. The usefulness of laser micromachining was demonstrated by realizing a semicircular cross-sectional microchannel, which is difficult to accomplish with the lithography-based technology. Rapid prototyping of an artificial vascular net...