BODIPY Photocage-Based Injectable Hydrogel for Light-Controlled Nanoparticle Release.

Area of Science:

• Biomaterials Science
• Drug Delivery Systems
• Photochemistry

Background:

• Light-controlled drug release offers therapeutic advantages but is limited by poor light penetration in tissues.
• Developing photoresponsive systems that function at clinically relevant depths is crucial for in vivo applications.

Purpose of the Study:

• To create an injectable and photodegradable hydrogel for controlled therapeutic release within subcutaneous tissue.
• To overcome the limitations of light penetration for in vivo photoresponsive drug delivery.

Main Methods:

• Formulation of a hydrogel using a 2-arm photocage with azide and a BCN-terminated 4-arm PEG.
• Gelation via strain-promoted azide-alkyne cycloaddition (SPAAC) upon mixing precursors.
• Controlled photocleavage and degradation using green light irradiation.
• Encapsulation and photo-release of nanoparticles.

Main Results:

• The hydrogel precursors are water-soluble, low-viscosity, and injectable via 23G needles.
• Rapid gelation occurs within minutes via SPAAC.
• Precise control over hydrogel degradation and drug release was achieved with green light.
• Successful encapsulation and light-triggered release of nanoparticles were demonstrated.
• Ex vivo studies in porcine models and human skin confirmed functionality and biocompatibility.

Conclusions:

• The developed injectable hydrogel enables precise, light-controlled drug delivery in subcutaneous tissues.
• This system effectively addresses the challenge of light penetration for photoresponsive therapeutics.
• The hydrogel shows promise for improving treatment compliance and patient quality of life in chronic conditions.