Synthesis of biocompatible BSA-GMA and two-photon polymerization of 3D hydrogels with free radical type I photoinitiator

Int J Bioprint. 2023 Mar 12;9(5):752. doi: 10.18063/ijb.752. eCollection 2023.

Abstract

Although the development of three-dimensional (3D) printing technology is growing rapidly in the biomedical field, it remains a challenge to achieve arbitrary 3D structures with high resolution and high efficiency. Protein hydrogels fabricated by two- photon polymerization (TPP) have excellent mechanical properties, high precision, and 3D architecture. However, a large number of the amino acid group in bovine serum albumin (BSA) would be consumed when the protein-based hydrogels use dyes of free radical type II photoinitiators. In this study, we use glycidyl methacrylate (GMA) to modify BSA molecules to obtain a series of BSA-GMA materials, allowing the protein material to be two-photon polymerized with a water-soluble free radical type I photoinitiator. The precisely controllable 3D structure of the BSA-GMA hydrogel was fabricated by adjusting the concentration of the precursor solution, the degree of methacrylation, and the processing parameters of the TPP technique. Importantly, BSA-GMA materials are free of acidic hazardous substances. Meanwhile, the water-soluble initiator lithium phenyl (2,4,6-trimethylbenzoyl) phosphite (LAP) allows TPP on the vinyl group of the GMA chain and thus without consuming its amino acid group. The as-prepared BSA-GMA hydrogel structure exhibits excellent autofluorescence imaging, pH responsiveness, and biocompatibility, which would provide new avenues for potential applications in tissue engineering and biomedical fields to meet specific biological requirements.

Keywords: Biocompatible scaffold; Bovine serum albumin; Free radical type I initiator; Hydrogel; Two-photon polymerization.