Microfabrication of hydrogels based on femtosecond laser three-dimensional ablation

Hydrogels are widely used in biome dical applications such as drug delivery and tissue engineering. Micro-manufacturing of hydrogels can open new opportunities. Methods such as photolithography and soft lithography rely on masks for hydrogel shaping, while extrusion and inkjet printing are limited in their ability to achieve high-precision. On the other hand, femtosecond laser direct writing (FsLDW) technology enables programmable construction of arbitrary microscopic patterns. Previous works of FsLDW mainly focus on two-photon induced polymerization for three-dimensional (3D) manufacturing. This study aims to exploit high-energy lasers to induce bond cleavage in polymers, achieving 3D subtractive processing of hydrogels. A resolution 900 nm was achieved. Moreover, the resulting patterned channels exhibit multicolor fluorescence, introducing a novel design concept that is significant for the development of diverse functionalized hydrogels.