Chemically crosslinkable thermosensitive polyphosphazene gels as injectable materials for biomedical applications

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Chemical Engineering

Background:

• Injectable hydrogels are promising for biomedical applications.
• Developing materials with tunable mechanical properties and controlled degradation is crucial.
• Poly(organophosphazenes) offer a versatile platform for biomaterial design.

Purpose of the Study:

• To synthesize and characterize chemically crosslinkable and thermosensitive poly(organophosphazenes).
• To evaluate their potential as injectable biomaterials for tissue engineering and protein delivery.
• To investigate the influence of polymer structure on hydrogel properties and degradation.

Main Methods:

• Synthesis of poly(organophosphazenes) with thiol, hydrophobic, and hydrophilic groups.
• Hydrogel formation via hydrophobic interactions and thiol cross-linking (divinyl sulfone, PEG divinyl sulfone).
• Characterization using Field Emission-Scanning Electron Microscopy (FE-SEM), swelling tests, rheology, and in vivo degradation studies.

Main Results:

• Aqueous polymer solutions formed hydrogels at body temperature.
• Gel strength was enhanced by hydrophobic interactions and thiol cross-linking.
• Hydrogel network structure, gel strength, and degradation rate were tunable based on thiol content.
• In vivo studies demonstrated controlled degradation of dual cross-linked gels.

Conclusions:

• Chemically crosslinkable and thermosensitive poly(organophosphazenes) can be engineered as injectable hydrogels.
• Tunable network properties and degradation rates make them suitable for biomedical applications.
• These materials show significant promise for tissue engineering and controlled protein delivery systems.