School of Mechanical Engineering, Sharif University of Technology, Tehran, Iran; Stem Cell and Regenerative Medicine Institute, Sharif University of Technology, Tehran 11155-9161, Iran.
School of Mechanical Engineering, Sharif University of Technology, Tehran, Iran; Stem Cell and Regenerative Medicine Institute, Sharif University of Technology, Tehran 11155-9161, Iran.
Int J Biol Macromol. 2023 Dec 31;253(Pt 3):126929. doi: 10.1016/j.ijbiomac.2023.126929. Epub 2023 Sep 17.
The replication of skin's dermal and epidermal morphology within a full-thickness wound using a bi-layer hydrogel to cater to their distinct needs is a compelling pursuit. Moreover, human placenta extract (HPE), containing a diverse array of bioactive agents, has proven to be effective in promoting the wound healing process and enhancing epidermal keratinocytes. This study presents a multifunctional bi-layer hydrogel incorporating HPE for accelerating full-thickness wound healing through sustained HPE release, inhibition of bacteria invasion, and promotion of cell proliferation. The upper layer of the scaffold, known as the dressing layer, is composed of carboxymethyl cellulose and sodium alginate, serving as a supportive layer for cell proliferation. The under layer, referred to as the regenerative layer, is composed of chitosan and gelatin, providing an extracellular matrix-like, porous, moist, and antibacterial environment for cell growth. The scaffold was optimized to replicate the morphology of the dermal and epidermal layers, with suitable fibroblast infiltration and a pore size of approximately 283μm. Furthermore, the degradation rate of the samples matched the wound healing rate and persisted throughout this period. The sustained HPE release rate, facilitated by the degradation rate, was optimized to reach ~98% after 28 days, covering the entire healing period. The samples demonstrated robust antibacterial capabilities, with bacterial inhibition zone diameters of and 2.63±0.12cm for S. aureus and E. coli, respectively. The biocompatibility of the samples remained at approximately 68.33±4.5% after 21 days of fibroblast cell culture. The in vivo experiment indicated that the HPE@Bilayer hydrogel promotes the formation of new blood vessels and fibroblasts during the early stages of healing, leading to the appropriate formation of granulation tissue and a wound contraction rate of (79.31±3.1)%. Additionally, it resulted in the formation of a thick epidermal layer (keratinization) that effectively covered all the impaired areas, achieving a wound contraction rate of 95.83±6.3% at the late stage of wound healing. Furthermore, immunohistochemistry staining for CD31 and TGF-β revealed that the HPE@Bilayer group had 22 blood vessels/field and 34%-66% immunoactive cells, respectively, after 14 days of healing. However, by day 21, angiogenesis and TGF-β expression had declined, demonstrating that the wounds had been successfully treated with minimal scarring.
利用双层水凝胶复制全层伤口的皮肤真皮和表皮形态，以满足它们各自的需求，这是一项引人注目的研究。此外，含有多种生物活性物质的人胎盘提取物（HPE）已被证明能有效促进伤口愈合过程和增强表皮角质形成细胞。本研究提出了一种多功能双层水凝胶，其中包含 HPE，通过持续释放 HPE、抑制细菌入侵和促进细胞增殖来加速全层伤口愈合。支架的上层，即敷料层，由羧甲基纤维素和海藻酸钠组成，作为细胞增殖的支撑层。下层，即再生层，由壳聚糖和明胶组成，为细胞生长提供细胞外基质样的多孔、潮湿和抗菌环境。支架经过优化，以复制真皮和表皮层的形态，具有合适的成纤维细胞浸润和大约 283μm 的孔径。此外，样品的降解率与伤口愈合率相匹配，并在整个愈合期间持续存在。通过降解率优化 HPE 的释放速率，在 28 天后达到约 98%，覆盖整个愈合期。样品表现出强大的抗菌能力，金黄色葡萄球菌和大肠杆菌的抑菌圈直径分别为和 2.63±0.12cm。经过 21 天的成纤维细胞培养，样品的生物相容性保持在约 68.33±4.5%。体内实验表明，HPE@双层水凝胶在愈合早期促进新血管和成纤维细胞的形成，导致适当的肉芽组织形成和（79.31±3.1）%的伤口收缩率。此外，它形成了一层厚厚的表皮层（角化），有效地覆盖了所有受损区域，在伤口愈合的后期实现了 95.83±6.3%的伤口收缩率。此外，CD31 和 TGF-β的免疫组织化学染色显示，在愈合的第 14 天，HPE@双层组每个视野有 22 个血管和 34%-66%的免疫活性细胞。然而，到第 21 天，血管生成和 TGF-β表达下降，表明伤口已成功治愈，几乎没有疤痕。
