Feasibility assessment of polyvinyl alcohol-based bioresorbable cardiovascular stents manufactured via solvent-cast direct writing extrusion

Background: Bioresorbable stents represent a promising approach in cardiovascular interventions compared to drug-eluting stents. Additive manufacturing, particularly ink deposition, offers customization and versatility. This study delves into the potential of solvent cast direct-write 3D printing to fabricate cardiovascular stents using environmentally friendly solvents. Methodology: Polyvinyl alcohol, a biocompatible synthetic polymer that dissolves in water, was investigated as a suitable material for stent fabrication. The polymer was deposited on a rotating mandrel and subsequently crosslinked to establish a pseudostable state. Test specimens and stents were fabricated for characterization of both the material and stent dynamics. Results: This outcome is potentially suitable for deployment in the human body environment and adaptable to various biomedical applications, such as drug delivery patches or implants. The research optimized the fabrication of various stent geometries using polyvinyl alcohol and evaluated the kinetics of the working environment of these stents. Specifically, the 8-cell diamond stent showed remarkable characteristics, such as a high overexpansion of more than 0.5 mm, a compression force of 0.02 N and an elastic recovery of 88.85 %, with a strut thickness of 50.25 mu m. Additionally, the study discusses the possibility of sterilizing polyvinyl alcohol with different methods, ethanol and autoclave were selected. Conclusions: The results indicate that autoclaving leads to an increase in crystallinity. This yields a decrease in water absorption and an increase in mechanical properties. These results suggest that polyvinyl alcohol-based stents fabricated by solvent-cast direct writing are potential candidates for bioresorbable stent design.