Porous Chitosan Films Support Stem Cells and Facilitate Sutureless Tissue Repair

Photochemical tissue bonding with chitosan-based adhesive films is an experimental surgical technique that avoids the risk of thermal tissue injuries and the use of sutures to maintain strong tissue connection. This technique is advantageous over other tissue repair methods as it is minimally invasive and does not require mixing of multiple components before or during application. To expand the capability of the film to beyond just a tissue bonding device and promote tissue regeneration, in this study, we designed bioadhesive films that could also support stem cells. The films were modified with oligomeric chitosan to tune their erodibility and made porous through freeze-drying for better tissue integration. Of note, porous adhesive films (pore diameter ∼110 μm), with 10% of the chitosan being oligomeric, could retain similar tissue bonding strengths (13-15 kPa) to that of the nonporous chitosan-based adhesives used in previous studies when photoactivated. When tested in vitro, these films exhibited a mass loss of ∼20% after 7 days, swelling ratios of ∼270-300%, a percentage elongation of ∼90%, and both a tensile strength and Young's modulus of ∼1 MPa. The physical properties of the films were suitable for maintaining the viability and multipotency of bone-marrow-derived human mesenchymal stem cells over the duration of culture. Thus, these biocompatible, photoactivated porous, and erodible adhesive films show promise for applications in controlled cell delivery and regenerative medicine.