Injectable, Ribbon-Like Microconfetti Biopolymer Platform for Vaccine Applications

Area of Science:

• Biomaterials Science
• Immunology
• Vaccine Technology

Background:

• High-aspect-ratio acetalated dextran microconfetti (MC) previously demonstrated sustained subcutaneous drug release.
• MC offer potential as a novel injectable vaccine delivery platform.

Purpose of the Study:

• To investigate the efficacy of MC as an injectable vaccine platform.
• To evaluate MC's ability to deliver adjuvants and antigens and stimulate immune responses.

Main Methods:

• MC fabrication via electrospinning and high-shear homogenization.
• Loading MC with resiquimod adjuvant and adsorbing ovalbumin antigen.
• In vitro assessment of cytokine production and cytotoxicity in dendritic cells.
• In vivo evaluation of humoral and Th1-skewed immune responses after subcutaneous injection.

Main Results:

• Steady release of resiquimod from MC created an in vivo immunostimulatory depot.
• Resiquimod-loaded MC stimulated inflammatory cytokine production without cytotoxicity.
• MC of various sizes were internalized by antigen-presenting cells, facilitating antigen presentation.
• Blank MC stimulated a humoral response, while adjuvant-loaded MC enhanced immune responses, particularly Th1-skewed responses.

Conclusions:

• Acetalated dextran MC represent a versatile injectable vaccine platform.
• MC effectively deliver adjuvants and antigens, modulating immune responses.
• MC fabrication allows for tunable immune stimulation, highlighting their potential in vaccine development.