Figure 3.

Laser ablation and optical breakdown of PEGylated fibrinogen. (a and b) The phase-contrast micrographs of microchannels inscribed into hydrogel-B samples using nanosecond (a) or femtosecond (b) laser ablation with varying power shows the visible damage to the hydrogel caused by the ablation. The percent of maximum power used is inscribed (nanosecond) or indicated (femtosecond) next to each microchannel, and shown relative to the corresponding laser's peak intensity (in W/cm²; scale bar = 100 μm). (c and d) SDS-PAGE (4–12% gradient gel) of homogenized samples of hydrogel-B exposed to different nanosecond (c) or femtosecond (d) laser energy levels shows progressive protein breakdown at higher energy levels in the nanosecond ablation, and no significant breakdown in the 6.8 × 10¹² W/cm² femtosecond peak energy (α, β, and γ chains of fibrinogen are indicated). Control samples shown include fibrinogen solution reduced (c1), fibrinogen solution nonreduced (c2), PEGylated fibrinogen solution reduced (c3), PEGylated fibrinogen solution nonreduced (c4), and homogenized PEGylated fibrinogen solution nonreduced (c5).