Solvent Exchange Method for Protein-based Bioplastics

Abstract

Additive manufacturing (AM) has seen significant growth in tissue engineering and medical device applications, with bioplastics emerging as preferred materials due to their biocompatibility and environmental sustainability. However, these bioplastic systems typically contain high water content, presenting significant challenges during the drying process. The high water content leads to anisotropic shrinkage, resulting in undesirable bending and warping of printed structures, which compromises their dimensional accuracy and functional properties. This study investigates the optimization of solvent exchange protocols using ethanol to produce dimensionally stable prints from bovine serum albumin (BSA) and poly(ethylene glycol) diacrylate (PEGDA) resin through vat photopolymerization. Our methodology focuses on establishing precise drying procedures that maintain the structural integrity of the printed components while preserving their mechanical properties. The results demonstrate that solvent-exchanged samples exhibited less than 30% volume reduction compared to control samples, indicating superior dimensional stability. Mechanical characterization revealed that the solvent exchange process did not significantly alter the material's mechanical properties, suggesting the preservation of its structural functionality. Thermal analysis was conducted to quantify the residual water content in solvent-exchanged samples, providing insights into the effectiveness of the dehydration process. Furthermore, complex printed structures subjected to the optimized solvent exchange protocol showed significantly reduced shrinkage, bending, and warping compared to untreated samples. This work establishes a robust methodology for producing high-resolution, dimensionally stable BSA-PEGDA prints suitable for consistent mechanical testing and complex structure fabrication, potentially advancing the field of biofabrication for tissue engineering and medical device applications.