Evaluation of a bilayered, micropatterned hydrogel dressing for full-thickness wound healing

Abstract

Nearly 12 million wounds are treated in emergency departments throughout the United States every year. The limitations of current treatments for complex, full-thickness wounds are the driving force for the development of new wound treatment devices that result in faster healing of both dermal and epidermal tissue. Here, a bilayered, biodegradable hydrogel dressing that uses microarchitecture to guide two key steps in the proliferative phase of wound healing, re-epithelialization, and revascularization, was evaluated in vitro in a cell migration assay and in vivo in a bipedicle ischemic rat wound model. Results indicate that the Sharklet TM -micropatterned apical layer of the dressing increased artificial wound coverage by up to 64%, P ¼ 0.024 in vitro. In vivo evaluation demonstrated that the bilayered dressing construction enhanced overall healing outcomes significantly compared to untreated wounds and that these outcomes were not significantly different from a leading clinically available wound dressing.Collectively, these results demonstrate high potential for this new dressing to effectively accelerate wound healing.Keywords: Micropattern, wound healing, biomaterials, hydrogel, gelatin, microarchitectureExperimental Biology and Medicine 2016; 241: 986-995.

Capillary alginate gel (Capgel™) for the treatment of full-thickness dermal wounds in a hypoxic mouse model

“…[40] Previously, Capgel TM has been used in conjunction with a micro patterned gelatin-based construct, Sharklet. [41] Using a similar grading scheme for wound outcome, the Sharklet dressing did not yield any statistical differences in rates of re-epithelization, though this may be due to the mouse model, which, unlike humans or pigs, relies primarily on contracture to close a dermal wound. Further experimentation to increase sample size, possibly in a different, more cooperative animal model (e.g., porcine), would allow for improved analysis.…”

Manufacturing micropatterned collagen scaffolds with chemical-crosslinking for development of biomimetic tissue-engineered oral mucosa

“…Although chemically crosslinked hydrogels are apt to be less biocompatible than physically crosslinked ones due to the potential cytotoxicity of the residual chemicals and reagents, EDC has been utilized in many soft tissue-engineered products, including CollaMend and Sharklet. These facts indicate insignificance of EDC cytotoxicity 17,[29][30][31] . However, the stability of collagen gel treated with EDC decreases the degradation rate in vivo 32,33 .…”

“…In this work, we have extended our previous technique, combined with MEMS process for fabricating negative molds, to engineer collagen scaffolds, applying it to different designs of DEJ-like micropattern. Several reports have shown a similar strategy to develop micropattern of intricate DEJ-like structure onto the surface of hydrogel scaffolds using photolithography as dermal substitutes for clinical application to reconstruct tissue defects 16,17 . However, their basic microarchitecture was a "grooved" pattern only, which is not as complex as the prototypes produced in this study.…”

Recent developments in drug-eluting dressings for the treatment of chronic wounds

“…The controlled release of bFGF from a heparin-based coacervate accelerated the wound healing by promoting cell proliferation, re-epithelialization by stimulating secretion of VEGF, and collagen deposition in vivo, in a mouse cutaneous wound model, where the heparin stabilizes the bFGF and prolongs its half-life [12]. The sequential activity of proadrenomedullin N-terminal 20 peptide and bemiparin (a fractionated low-molecular-weight heparin) topically from a bilayered construct favored epithelialization in both ischemic and non-ischemic model [13]. The use of growth factors and peptides topically presents some challenges due to biological degradation by the enzymes present in the wound site which lead to a decreased therapeutic efficacy.…”