Photopolymerizable hydrogels for implants: Monte-Carlo modeling and experimental in vitro validation

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Medical Device Engineering

Background:

• Photopolymerization is crucial for bio-applications like drug delivery and tissue engineering.
• Current methods often use probes for liquid delivery and light curing, but this approach is not fully understood.
• Minimally invasive techniques require precise control over hydrogel formation within biological environments.

Purpose of the Study:

• To develop and validate a Monte Carlo model for simulating photopolymerization of injected hydrogels.
• To investigate the influence of dynamic optical properties and boundaries on hydrogel shape and volume.
• To explore methods for enhancing photopolymerization efficiency in confined biological spaces.

Main Methods:

• Developed a Monte Carlo model incorporating dynamic absorption, scattering, and solid-liquid boundaries.
• Validated the model using poly(ethylene glycol) dimethacrylate hydrogels, comparing simulated and experimental volume growth rates.
• Conducted in situ experiments and simulations of photopolymerization within tissue cavities.

Main Results:

• The model demonstrated excellent agreement with experimental data for hydrogel volume growth rates.
• Photopolymerization efficiency in a 152 mm³ cavity was significantly increased by adding scattering lipid particles (achieving 100% volume) compared to without particles (38 mm³).
• The study highlights the critical role of scattering in overcoming light penetration limitations.

Conclusions:

• The proposed Monte Carlo model offers a robust and straightforward method for analyzing complex photopolymerization scenarios.
• The findings suggest that incorporating scattering agents can substantially improve the efficacy of minimally invasive photopolymerization techniques.
• This research provides valuable insights for designing and optimizing photopolymerized hydrogels in various biomedical applications.