Fabrication of three-dimensional metal structures embedded in hydrogel by using femtosecond laser ablation and electroplating

We demonstrated a method of fabricating three-dimensional (3D) metal structures in hydrogels with good conductivity by using femtosecond laser ablation and electroplating. The hydrogel containing Ag⁺ was first ablated by a femtosecond laser to form microchannels with an entrance achieving surface and then sandwiched between the anode and cathode to operate electroplating. Silver structures were formed along the microchannel from the microchannel entrance close to the cathode due to reduction of Ag⁺. The average resistivity of metal structures is measured to be about 4 × 10⁻⁷ Ω m. A tetrahedron metallic microstructure embedded in hydrogel by this method was demonstrated to show its ability of 3D micromachining.