In silico Investigation of Light Intensity and Temperature Distribution in Tissue for Vaccine Adjuvant Using NIR...

Area of Science:

• Biomedical Engineering
• Immunology
• Photomedicine

Background:

• Vaccines are crucial for disease prevention but often face challenges with antigen distribution and adjuvant safety.
• Current adjuvants can cause side effects, driving the need for safer, more effective immune-enhancing technologies.
• Novel laser adjuvants offer a non-invasive approach to boost vaccine efficacy.

Purpose of the Study:

• To simulate the effective reaction area and thermal safety of a novel laser adjuvant for vaccines.
• To develop and validate numerical skin models for evaluating laser adjuvant effects in mice and humans.
• To assess the penetration depth and thermal safety of near-infrared laser irradiation on skin.

Main Methods:

• Developed numerical models of mouse and human skin (epidermis, dermis, connective tissue).
• Utilized ray tracing and heat conduction simulations for laser adjuvant analysis.
• Irradiated skin models with 1270 nm wavelength laser at 1.0 and 2.0 W/cm² for 180 seconds.

Main Results:

• Laser irradiation at 2.0 W/cm² reached mouse mast cells with a maximum temperature of 38.6°C, indicating safety.
• Simulations confirmed effective light penetration to mast cells in mouse skin models.
• In human skin models, 1270 nm laser light at 2.0 W/cm² did not adequately penetrate mast cells.

Conclusions:

• The developed numerical models are valuable for evaluating laser adjuvant safety and efficacy.
• Optimized laser irradiation parameters are necessary for effective adjuvant effects in human skin.
• Further research is needed to tailor laser adjuvant conditions for human vaccination strategies.