The experimental use of poly (alcohol-vinyl) (PVA) as a skin curative is increasing widely. However, the use of this hydrogel is challenging due to its favorable properties for microbiota growth. The association with silver nanoparticles (AgNPs) as an antimicrobial agent turns the match for PVA as a dressing, as it focuses on creating a physical barrier to avoid wound dehydration. When associated with extracellular components, such as the collagen matrix, the device obtained can create the desired biological conditions to act as a skin substitute. This study aimed to analyze the anti-microbiological activity and the in vitro and in vivo responses of a bilaminar device of PVA containing AgNPs associated with a membrane of collagen–hyaluronic acid (col-HA). Additionally, mesenchymal stem cells were cultured in the device to evaluate in vitro responses and in vivo immunomodulatory and healing behavior. The device morphology revealed a porous pattern that favored water retention and in vitro cell adhesion. Controlled wounds in the dorsal back of rat skins revealed a striking skin remodeling with new epidermis fulfilling all previously injured areas after 14 and 28 days. No infections or significant inflammations were observed, despite increased angiogenesis, and no fibrosis-markers were identified as compared to controls. Although few antibacterial activities were obtained, the addition of AgNPs prevented fungal growth. All results demonstrated that the combination of the components used here as a dermal device, chosen according to previous miscellany studies of low/mid-cost biomaterials, can promote skin protection avoiding infections and dehydration, minimize the typical wound inflammatory responses, and favor the cellular healing responses, features that give rise to further clinical trials of the device here developed

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A recent and quite promising technique for bone tissue engineering is the 3D printing, peculiarly regarding the production of high-quality scaffolds. The 3D printed scaffold strictly provides suitable characteristics for living cells, in order to induce treatment, reconstruction and substitution of injured tissue. The purpose of this work was to evaluate the behavior of the 3D scaffold based on Poly(L-co-D,L lactic acid-co-Trimethylene Carbonate) (PLDLA-TMC), which was designed in Solidworks™ software, projected in 3D Slicer™, 3D printed in filament extrusion, cultured with mesenchymal stem cells (MSCs) and tested in vitro and in vivo models. For in vitro study, the MSCs were seeded in a PLDLA-TMC 3D scaffold with 600 μm pore size and submitted to proliferation and osteogenic differentiation. The in vivo assays implanted the PLDLA-TMC scaffolds with or without MSCs in the calvaria of Wistar rats submitted to 8 mm cranial bone defect, in periods of 8–12 weeks. The results showed that PLDLA-TMC 3D scaffolds favored adherence and cell growth, and suggests an osteoinductive activity, which means that the material itself augmented cellular differentiation. The implanted PLDLA-TMC containing MSCs, showed better results after 12 weeks prior grafting, due the absence of inflammatory processes, enlarged regeneration of bone tissue and facilitated angiogenesis. Notwithstanding, the 3D PLDLA-TMC itself implanted enriched tissue repair; the addition of cells known to upregulate tissue healing reinforce the perspectives for the PLDLA-TMC applications in the field of bone tissue engineering in clinical trials.

An increasing interest in regenerative medicine has been an approach with natural products used for assorted skin treatments. Propolis from Apis mellifera species of bees have shown high acceptance due to antimicrobial and anti-inflammatory properties. However, just a few propolis types presents stronger effects in controlling inflammation. The current work describes an organic propolis recently isolated, named as OP6, that presented strong anti-inflammatory influences in vivo when associated with EDTA cross-linked hydrogel, used as a curative device in second-degree burns in a murine model. We developed a cellulose acetate hydrogel cross-linked with ethylenediaminetetraacetic dianhydride (HAC-EDTA) as a polymeric matrix for a bandage based on an ethanolic extract of propolis at 15%, 30%, and 60% (w/v) for treating second-degree burns. In vivo studies were carried out in Wistar rats divided into three groups: negative control (only lesion), positive control (lesion with HAC-EDTA film), and treatment group (lesion with the HAC-EDTA + OP6 at 15%, 30%, and 60%). Each group was randomized and equally subdivided into two subgroups according to the period of bandage wearing (7 and 14 days). Previous work of this research group selected the propolis OP6 sample source as the best candidate for the in vivo study. HAC-EDTA + OP6 15%, 30%, and 60% films demonstrated a concentration-dependent release rate, with the highest amount of propolis released after tests (484.3 mg) by HAC-EDTA enriched with the highest concentrated extract of propolis. HAC-EDTA + OP6 films were efficient in preventing infections, promoting lesion retraction, and tissue regeneration. The HAC-EDTA + OP6 30% treatment was more efficient, revealing a reduced inflammatory process and stimulating skin regeneration. The designed HAC-EDTA + propolis films were shown as promising tools for second-degree burns treatment, accelerating healing process to a full recovery tissue repair after 14 days.