Chitosan–hyaluronic acid hydrogel coated poly(caprolactone) multiscale bilayer scaffold for ligament regeneration

• Stacked Ch-HA hydrogel coated PCL aligned/random multiscale fibers were developed.
• The coated scaffold showed enhanced protein adsorption and cytocompatibility.
• Ligament fibroblast cells attached along the fiber direction in all the scaffolds.
• Higher cell retention was observed after hydrogel coating on fibers.
• Ch-HA hydrogel coating on PCL aligned multiscale would aid in ligament regeneration.

Ligament tears, seen in young athletes to elderly people, pose a very challenging problem to achieve complete healing, due to its hypocellularity that decelerate regeneration of ligament after injury. Tissue engineering is an approach for the ligament regeneration that optimizes the response of cell–biomaterial interaction to fasten regeneration using engineered scaffolds that mimic the native environment. Electrospinning techniques and hydrogels are useful to engineer the structure of ligament. In this study, electrospun multiscale fibrous scaffold of PCL aligned microfibers/random nanofibers (PCL aligned multiscale fibers) and PCL random microfibers/nanofibers (PCL random multiscale fibers) were developed. Chitosan–hyaluronic acid hydrogel coating was done on these fibrous scaffolds and this was layered to form a bilayered construct. The developed scaffold was characterized by SEM, FTIR, and tensile testing. Protein adsorption studies show better protein adsorption on coated scaffolds compared to uncoated scaffolds which further improved the cell viability as determined by Alamar blue assay and DNA quantification by Pico green assay. Rabbit ligament fibroblast cell attachment and infiltration study conducted on the scaffolds showed cell elongation along the aligned fibers, which would be advantageous in the need to align cells along the direction of force in native ligament environment. Hydrogel coating on PCL random multiscale fibers show better cell infiltration. This study implies the use of hydrogel coated systems to provide a reservoir for cells and nutrients and further modifications of these systems would make it promising for ligament regeneration.