Parameters optimization for biological molecules patterning using 248-nm ultrafast lasers

Laser-induced forward transfer has been used for the deposition of photoactive biotin in micron-scale patterns. The process uses a 500 fs pulsed KrF laser beam to transfer small amounts of a liquid solution target as micron-size droplets to a substrate placed parallel and in close proximity to it. The biomolecules remain active after the transfer; this is demonstrated through fluorescence assays. In addition to the laser parameters, those regarding the target composition and the receiving surface for the miniaturization of the transferred patterns have been studied and optimized. Droplets as small as 5 μm have been obtained by reducing the target thickness and transfer energy; by increasing the percentage of glycerol added in the biomolecules solution and by using hydrophobic surfaces as receiving substrates. The influence of the glycerol addition and the hydrophobicity of the receiving surfaces on the activity of the transferred biomolecules have also been studied.