PH-Triggered, Lymph Node Focused Immunodrug Release by Polymeric 2-Propionic-3-Methyl-maleic Anhydrides with...

Area of Science:

• Biomaterials Science
• Immunology
• Polymer Chemistry

Background:

• Spatial control of innate immunity is crucial for effective vaccines and cancer therapies, minimizing off-target effects.
• Lipid-polymer amphiphiles naturally accumulate in lymphoid tissues after local administration.
• Stimuli-responsive carriers are needed for precise control over immune cell activation within draining lymph nodes.

Purpose of the Study:

• To develop pH-sensitive, cholesteryl end-group functionalized polymers for controlled immunoactivation of draining lymph nodes.
• To create polymer carriers capable of targeted delivery and triggered release of immunostimulatory agents.
• To investigate the in vivo efficacy of these carriers for enhancing immune responses.

Main Methods:

• Synthesis of methacrylamide-based polymers with pendant 2-propionic-3-methylmaleic anhydride groups via RAFT polymerization.
• Functionalization with a cholesterol chain-transfer agent and conjugation with amines (primary for irreversible, secondary for pH-sensitive linkage).
• Hydrophilization with PEG chains and evaluation of cellular uptake, pH-triggered drug release, lymph node drainage, and in vivo immune cell maturation.

Main Results:

• Developed pH-sensitive polymer amphiphiles with cholesteryl end groups.
• Demonstrated pH-responsive release of conjugated cargos (e.g., Toll-like receptor 7/8 agonists) upon acidification.
• Showed efficient lymph node drainage and enhanced maturation of antigen-presenting cells in vivo after subcutaneous injection.

Conclusions:

• Cholesteryl-linked methacrylamide-based polymers with pH-sensitive anhydride side groups are effective carriers for targeted immunodrug delivery.
• These polymers enable controlled immunoactivation within draining lymph nodes, offering potential for improved vaccine and cancer therapy strategies.
• The pH-responsive nature allows for precise drug release, enhancing therapeutic outcomes and minimizing systemic side effects.