PCL and PLG Scaffold Fabrication and Optimization – UROP Symposium

PCL and PLG Scaffold Fabrication and Optimization

Natalie Wright

Research Mentor(s): Aaron Morris
Program: CCSFP
Authors: Natalie Wright, Sydney Wheeler, Pre-PhD Candidate, Aaron Morris, PhD

Abstract

Reproducible biomaterial scaffold fabrication plays a critical role in the development of therapeutics and medical devices with diverse applications, including tissue engineering and immunotherapy. Designing biomaterial scaffolds to interact with specific cell types and alter cellular behavior is a growing area of research. One type of adaptive immune cell called T-cells express receptors specific to unique peptide antigens. By delivering disease-relevant antigens from implantable biomaterial scaffolds, it is possible to enrich disease-specific T-cells. To achieve the objective of enriching T-cells for inflammatory diseases, it is essential to fabricate scaffolds that are reproducible and uniform. We hypothesized that optimizing polymer and salt content during scaffold fabrication would enhance uniformity of the scaffolds. Two polymers were tested, both polycaprolactone (PCL) and poly(lactide-co-glycolide) (PLG). Amounts of polymer were weighed out to obtain percent weight/volume from 12% to 15% when dissolved in chloroform. Sodium chloride crystals were sieved to achieve a particle size in the range of 250-425 μm. The salt crystals were then mixed with the polymer solution at a ratio of 3.9 g NaCl per 1 mL of polymer mixture. The resulting mixture was cast in cylindrical molds and allowed to undergo solvent evaporation overnight. The scaffolds were removed from the molds, salt leached in dH2O and biopsy punched to create individual scaffolds of 5 mm in diameter. To ensure the removal of residual solvents, the scaffolds were lyophilized overnight. Subsequently, mass was measured for each individual scaffold to evaluate uniformity. In conclusion from several repetitions of this experiment, both PCL and PLG scaffolds in the 14% weight/volume category were the most uniform . Current work includes examining the salt content when 13% to 14% weight/volume ratios are mixed with salt ratios ranging from 3.7 g to 4.0 g per 1 mL of polymer mixture. By creating a reproducible scaffold, these experiments provide a platform for the enrichment of disease-specific T-cells using implantable biomaterial scaffolds conjugated with relevant antigens.

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