Electrospun soy protein-based scaffolds for skin tissue engineering and wound healing

Abstract

In order to bypass some of the limitations of currently available skin substitutes and wound dressings, we explored the use of bioactive scaffolds made of plant-derived proteins. We hypothesized that these “green” materials may confer bioactive properties to enhance wound healing and skin regeneration. We optimized the parameters for electrospinning fibrous scaffolds from soy protein isolate (SPI) with addition of 0.05% poly(ethylene oxide) (PEO) dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol, and characterized these scaffolds based on their physical and mechanical properties, degradation behavior, and in vitro biocompatibility. SPI/PEO scaffolds remained stable without further cross-linking, possessing mechanical properties similar to those reported for human skin, and supported the adhesion and proliferation of cultured primary human dermal fibroblasts alone and in organotypic co-culture with primary human epidermal keratinocytes. Using targeted PCR arrays and qPCR validation, we found similar gene expression profiles of fibroblasts cultured for 2h and 24h on SPI substrates and on collagen type I at both time points. On both substrates there was a pronounced time-dependent up-regulation of several genes related to extracellular matrix (ECM) remodeling, including MMP-10, MMP-1, collagen VII, integrin-α2 and laminin-β3, indicating that both plant- and animal-derived materials induce similar responses from the cells after initial adhesion, degrading substrate proteins and depositing ECM in a “normal” remodeling process.Electrospun SPI/PEO scaffolds were evaluated in vivo against Tegaderm™ wound dressing, a standard in wound care, in a full-thickness excision wound model in the hairless rat. SPI/PEO scaffolds promoted a slightly but not significantly faster initial wound closure than Tegaderm™. The similar quantitative response in both groups was corroborated by non-invasive optical measurements using functional near infrared spectroscopy (fNIR). Electrospun SPI/PEO scaffolds provided qualitative benefits over Tegaderm™, including greater compliance to the wound shape, and the tendency to absorb wound exudates. SPI/PEO scaffolds integrated well with the wound and detached naturally with the formed encrustation at day 7 that occurred in both treatment groups. SPI/PEO scaffolds are therefore promising as a new type of treatment for non-healing wounds, and further studies will help to elucidate potential mechanisms by which it promotes wound healing at a cellular and/or molecular level.%%%%Ph.D., Biomedical Engineering – Drexel University, 2011