Fabrication and <i>in vivo</i> characterization of FRESH-based 3D printed chitosan construct for small intestine regeneration

This study demonstrates the implantation of a 3D printed small intestine (SI) construct using alkali-dissolved chitosan ink and freeform reversible embedding of suspended hydrogels bioprinting technology. The research addresses the significant clinical challenges posed by inflammatory bowel disease (IBD) and short bowel syndrome (SBS), which often require surgical interventions leading to substantial loss of SI surface area. High costs, side effects, and donor shortages limit traditional treatments such as total parenteral nutrition and small bowel transplantation. Therefore, developing an engineered artificial intestine represents a critical need. The 3D printed constructs were evaluated through mechanical characterization, blood biocompatibility tests, antibacterial assays, and SI regenerative capacity. The mechanical properties indicated the constructs' ability to withstand significant deformation, while the blood compatibility tests showed minimal hemolysis and blood coagulation, supporting the material's suitability for implantation. Antibacterial tests revealed that the constructs could inhibit bacterial growth, reducing the risk of implant-associated infections. Following the implantation of the prepared constructs in rats, the post-implantation analysis indicated successful integration and biocompatibility with no significant adverse reactions. The biochemical parameters, like inflammatory markers, were slightly higher than the normal range. All other parameters, like bilirubin and albumins, etc, were in the normal range. This study highlights the potential of 3D printed chitosan-based constructs in organ regeneration and presents a promising solution for treating SBS and IBD. The findings support further exploration of the fabricated 3D printed biocompatible materials for medical applications in regenerative medicine and tissue engineering.