Oral mucosal vaccination using integrated fiber microneedles.

Area of Science:

• Biomedical Engineering
• Immunology
• Drug Delivery Systems

Background:

• The oral mucosa offers an accessible route for immunization, potentially inducing both local and systemic immunity.
• Challenges in oral mucosal immunogenicity evaluation stem from physical barriers and complex immune microenvironments.
• Previous microneedle research lacked optimization in delivery site, geometry, and release kinetics, limiting physiological response understanding.

Purpose of the Study:

• To develop advanced integrated fiber microneedle devices for tunable oral mucosal drug delivery.
• To investigate the impact of microneedle geometry, release kinetics, and delivery site on oral mucosal immunogenicity.
• To establish a versatile platform for controlled antigen delivery to the oral mucosa.

Main Methods:

• Fabrication of integrated fiber microneedles with adjustable geometries and release profiles (burst and sustained).
• Administration of microneedles to buccal and sublingual mucosa in preclinical models.
• Assessment of immune responses, including seroconversion and antigen-specific interferon-γ secretion in splenocytes.

Main Results:

• Integrated fiber microneedles successfully induced seroconversion and antigen-specific immune responses.
• Microneedle release kinetics significantly modulated the magnitude and dynamics of the immune response.
• Optimal microneedle length for immunogenicity was site-specific (longer for buccal, shorter for sublingual).
• The Th1/Th2 immune response phenotype varied with microneedle length.

Conclusions:

• Integrated fiber microneedles represent a promising, multifunctional delivery system for the oral mucosa.
• Tunable microneedle systems offer a powerful tool for dissecting and optimizing oral mucosal immunity.
• This technology supports further development of novel oral vaccine strategies.