Collagen-based Self Anti-inflammatory Wound Dressing

Inflammatory reaction is a key factor for wound healing. Excessive inflammation causestissue edema, ulcerateon and even putrescence, preventing wounds from repairing andrecovering. This clinical problem has attracted increasing attention. Recently, a clinicalresearch found that collagen and polyvinyl pyrrolidone (PVP) mixture showed significantanti-inflammation activity and could promote tissue reconstruction. This work aimed toprepare a hybrid sponge by mixing and crosslinking opened-ring PVP (ORPVP) with collagen,and further study its micro-structure, morphology, physic-chemical properties, stability,biocompatibility as well as inflammation inhibition activity. Finally, its potential as wounddressing will be evaluated.PVP is a widely used pharmaceutic adjuvant, and its lactam structure makes it extremelydifficult to be crosslinked with collagen to form a stable hydbird sponge. Thus, we firstlyestablished a method for preparing ORPVP by hydrolysized PVP to open the lactam rings andreleasing free carboxylic acid groups under high temperatured and pressure condtion. ORPVPwith different opened-ring ratio in the range of2.05%to4.85%was prepared. Their chemicalstructure was characterized and confirmed by FTIR and NMR.ORPVP with an opened-ring ratio of4.79%was chosen for preparing the hybrid sponges.ORPVP was firstly well mixed with collagen, lyophilized, crosslinked by EDC/NHS, and thenthe hybrid sponge was obtained. Sponges with different molar ratio of ORPVP to collagenwere also prepared for studying the effects of sponge composition on its properties. SEMobservation showed that the sponges possess homogeneous porous structure, with pore sizesranged from50to100μm. Physic-chemical characterization showed that sponges have greatswelling, moisture retention, and water vapor transmission properties. Though ORPVPslightly decreased swelling ratio, but it can greatly improved moisture retention, and reducethe loss of water. Col/ORPVP sponges also had improved stability against collagenaseenzymatic digestion. Col/ORPVP sponges showed good biocomtability in vitro as it did notcause hemolysis and had no cytotoxicity. Moreover, it could promote fibroblast attachmentand proliferation. Finally, the hybrid sponges had great inhibition on inflammatory cytokines,i.e., NO secretion reduced by57.10%, IL-6secretion reduced by50.89%, TNF-secretionreduced by22.46%and IL-1β secretion reduced by34.85%.Our results suggested that the hybrid sponges not only have excellent micro-structure,morphology, physic-chemical properties, stability, biocompatibility required for wounddressing materials, but also possess self anti-inflammation activities. This spongy materialwill have great potential to be developed as a new wound dressing in wound healing therapy.