Preparation of photo-reactive azidophenyl chitosan derivative for immobilization of growth factors

UV-crosslinking of chitosan/spent coffee ground composites for enhanced durability and multifunctionality

Spent coffee grounds (SCGs) have numerous applications and are often blended with polymers to create composites. However, SCGs are physically trapped within the polymer matrix, lacking strong chemical bonding. Therefore, this study has developed a new method for UV crosslinking composites using phenyl azide to address the issue of SCG leakage and limited durability of the composites. The main approach involves grafting phenyl azide onto chitosan, which is then combined with SCGs. When exposed to UV light, the SCGs become covalently linked to the chitosan chains. This method not only resolves the problem of chitosan's porous material fragility but also prevents SCG detachment, surpassing the performance of glutaraldehyde-crosslinked composites. Regarding applications, CS/SCG composites exhibit rapid heating and photothermal stability, making them suitable for use as thermal pads in evaporative water purification, enabling for the collection of pure water from contaminated sources. Furthermore, SCGs have the ability to adsorb metal ions, significantly enhancing the Cu2+ adsorption capacity of CS/SCG composites compared to pure CS, with an increase of more than twofold. This research not only presents a practical solution for stabilizing fillers within polymer matrices but also demonstrates the reusability of SCGs.

Antiadhesive Property of Photoreactive Azidophenyl Low-Molecular-Weight Chitosan in Rabbit Laminotomy Model

Newly developed photoreactive azidophenyl chitosan (P-ALMC) has characteristics of a transformable gel type and its outer layer could be sealed up like a film after UV radiation. We aim to evaluate the antiadhesive properties of P-ALMC through comparing it with hyaluronic acid-carboxymethylcellulose membrane (HA-CMC) in a rabbit laminotomy model. Laminotomies were performed at the L3-4, L4-5, and L5-6 levels in 41 rabbits and each level was randomly assigned to either receive saline (group I), HA-CMC (group II), or P-ALMC (group III). The extent of peridural fibrosis, density of fibroblasts and inflammatory cells, and dural thickness were evaluated at 6 and 12 weeks postoperatively. In the groups II and III, the extents of peridural fibrosis and dural thickness were significantly smaller than those in group I (P<0.001) and no differences between groups II and III were found at the postoperative 6 and 12 weeks. There were no differences of cell density among groups. P-ALMC showed effective antiadhesive properties comparable to HA-CMC and could be one of the candidates as an anti-adhesive agent for spine surgery even further study is required to identify the effectiveness of its unique characteristics as mechanical barrier.