Achieving bone regeneration with harmless visible light

The team, which includes Dr. Jinyoung Yun and graduate student Hyun Taek Woo, has developed an injectable adhesive hydrogel that uses visible light to simultaneously achieve cross-linking and mineralisation, eliminating the need for traditional bone grafts.

Bone defects, often resulting from trauma, infections, or congenital conditions, are becoming a critical challenge in aging populations. Conventional treatments typically involve bone grafts combined with bio adhesives, but they face significant limitations, such as difficulties in maintaining shape and adhesive strength within the body. These methods also struggle to deliver both effective bone regeneration and adhesion simultaneously.

The POSTECH team has addressed these challenges by introducing a hydrogel system activated by visible light, a safe alternative for medical use. The hydrogel’s unique properties allow it to cross-link, where its components bond and solidify, while simultaneously promoting mineralisation, forming calcium and phosphate essential for bone growth. Unlike earlier methods, which required separate preparation and mixing of bone grafts and adhesives, this system integrates both functions into a single injectable solution.

The hydrogel’s composition includes natural alginate from brown algae, mussel adhesive protein containing RGD peptides, calcium ions, phosphonodiols, and a photoinitiator. This coacervate-based formulation is designed to retain its shape and position after injection. When exposed to visible light, it undergoes cross-linking and forms amorphous calcium phosphate, which serves as a bone graft material. This process eliminates the need for additional grafts or adhesives, providing a streamlined approach to bone repair.

In animal trials, the hydrogel demonstrated promising results. It was effectively injected into femoral bone defects, adhered securely, and delivered essential components for bone regeneration. The findings highlight its potential to transform the treatment of bone defects, offering a simpler, safer, and more effective alternative to current methods.

Professor Cha commented: “The injectable hydrogel system for bone regeneration developed by our research team represents an innovative alternative to conventional complex treatments for bone diseases and will greatly advance bone tissue regeneration technology.”

This research was supported by the Ministry of Health and Welfare’s Dental Medical Technology Research and Development Project and the Integrated End-to-End Medical Device R&D Project.