Study on a series of water-soluble photoinitiators for fabrication of 3D hydrogels by two-photon polymerization

A series of water-soluble benzylidene cyclanone dyes T1-T3 were synthesized. Their photo-physical properties were investigated using UV-Vis spectra, fluorescence spectra and two-photon absorption spectra. The maximum two-photon absorption cross-sections (σ2) of T1-T3 in deionized water were determined as 567 GM, 808 GM and 231 GM. Using T1-T3 as photoinitiators (PIs) directly, 2D and 3D nano patterns based on two-photon crosslinking or polymerization of bovine serum albumin (BSA), water-soluble acrylic ester monomer (SR610) and hyaluronic acid derivative (HAGM) were successfully fabricated, respectively. Much lower threshold energies and wider fabrication windows were obtained in the formulations containing these PIs compared with commercial ones. Furthermore, the cytotoxicity study showed a favorable biocompatibility of these PIs, which indicated T1-T3 would have application prospects in 3D fabrication of biomaterials.