Full-thickness Wound Model Research Articles

Effects of ALA-PDT on the macrophages in wound healing and its related mechanisms in vivo and in vitro

BackgroundSeveral studies have suggested the effectiveness of photodynamic therapy (PDT) for wound healing. Macrophages are critical immune cells necessary for regulated inflammation during wound repair. However, the available information regarding the effects of PDT on macrophages during cutaneous wound healing remains insufficient. This study aimed to further investigate these aspects in vivo and in vitro. MethodsMouse full-thickness wound models were used as the study samples to investigate the therapeutic effects and mechanisms of 5-aminolevulinic acid (ALA) PDT. Wound healing rate, granulation tissue formation, local inflammation, M1/M2 macrophages differentiation, were measured at different time points treated by ALA-PDT. The polarization of macrophages induced by ALA-PDT was further evaluated in vitro using PCR and western blot analysis. ResultsALA-PDT could promote formation of granulation tissue, increase inflammatory infiltration and activate M1 macrophages in the early stage of injury. While, ALA-PDT could also facilitate absorption of granulation tissue, inhibit inflammatory infiltration and enhance M2 macrophages polarization in the later stage of wound repair. In vitro, ALA-PDT could modulate the ratio of M2 polarization to M1 polarization via NF-κB signaling pathway. ConclusionsALA-PDT topical application stimulates wound healing by regulating formation of granulation tissue, inflammatory process and M1/M2 macrophages differentiation. The study places a preliminary theoretical basis for topical ALA-PDT to be administered clinically in cutaneous wounds healing.

Porous Se@SiO2 Nanoparticles Enhance Wound Healing by ROS-PI3K/Akt Pathway in Dermal Fibroblasts and Reduce Scar Formation

Hypertrophic scarring, which is characterized by excessive extracellular matrix deposition and abnormal fibroblast homeostasis, is an undesirable outcome of dermal wound healing. Once formed, the scar will replace the normal function of local skin, and there are few noninvasive clinical treatments that can cure it. Se@SiO2 nanoparticles were synthesized to suppress oxidative stress, which induced the presence and activation of myofibroblasts during wound recovery. The characterization, antioxidant capacity and biological safety of Se@SiO2 NPs were evaluated. A full-thickness excisional wound model was established, and the wounds were divided into three groups. The re-epithelization and distribution of collagen fibers were assessed using hematoxylin and eosin staining and Masson’s trichome staining after specific treatments. Our results revealed that the Se@SiO2 NPs accelerated dermal wound healing and suppressed the formation of hypertrophic scars, accompanied by oxidative stress inhibition. Moreover, we found that Se@SiO2 NPs worked by activating the PI3K/Akt pathway and upregulating the phosphorylation of Akt. The findings of our study provide a new method to promote dermal scar-free wound healing by suppressing excessive oxidative stress and through PI3K/Akt pathway activation.

Preparation and characterization of a hydroxypropyl methylcellulose based wafer for simultaneous delivery of phenytoin and insulin as wound dressing material

In this study, a novel wafer based on Hydroxypropyl methylcellulose (HPMC) was prepared as a wound dressing for the simultaneous delivery of phenytoin (PT) and insulin; evaluation of the cutaneous wound repair property was performed too. Due to its low water solubility, PT was encapsulated in polymeric micelles (PM) by the film hydration method at different polymer/drug ratios and characterized in terms of particle size (PS), polydispersity index (PdI), zeta potential (ZP), drug loading (DL) %, entrapment efficiency (EE) %, and drug release. Then, the optimized PT loaded PM (PT-PM) was embedded in the wafers prepared from the HPMC polymer, alone or in combination with Carbopol 940 (CB) and xanthan gum (XG). This wafer also contained a fixed amount of insulin (PT-PM-Insulin-wafer). The obtained wafers were evaluated in terms of morphology, water uptake ability, porosity, bioadhesion and hardness features. Finally, the efficacy of the PT-PM-Insulin-wafer was assessed in full-thickness excision wound models. The optimized PT-PM showed the PS of 84.05 ± 1.80 nm, PdI of 0.28 ± 0.22, ZP of −3.38 ± 0.26 mV, DL of 15.63 ± 0.01%, EE of 92.66 ± 0.08%, and the release efficiency of 59.95 ± 0.03%. The results obtained from the XRD studies of PT-PM also demonstrated the transition of the crystalline nature of the PT to the amorphous form, while FTIR studies showed some intermolecular interaction of PT and the Soluplus® copolymer chain. It was also found that the incorporation of XG into HPMC wafers influenced the microstructure, thus increasing the porosity, water uptake ability and bioadhesion. Compared with other groups, the PT-PM-Insulin-wafer group showed the enhancement of wound closure through increasing collagen deposition and re-epithelialization. The present study, therefore, revealed that the PT-PM-Insulin-wafer group might have very promising applications for wound healing.

Urolithin A Promotes Angiogenesis and Tissue Regeneration in a Full-Thickness Cutaneous Wound Model

The treatment of chronic wound is an important topic of current clinical issue. Neovascularization plays a crucial role in skin wound healing by delivering fresh nutrients and oxygen to the wound area. The aim of this study was to investigate the mechanisms of urolithin A (UA) in angiogenesis during wound healing. The results of in vitro experiments showed that treatment with UA (5–20 μM) promoted the proliferation, migration, and angiogenic capacity of HUVECs. Furthermore, we investigated the effect of UA in vivo using a full-thickness skin wound model. Subsequently, we found that UA promoted the regeneration of new blood vessels, which is consistent with the results of accelerated angiogenesis in vitro experiments. After UA treatment, the blood vessels in the wound are rapidly formed, and the deposition and remodeling process of the collagen matrix is also accelerated, which ultimately promotes the effective wound healing. Mechanistic studies have shown that UA promotes angiogenesis by inhibiting the PI3K/AKT pathway. Our study provides evidence that UA can promote angiogenesis and skin regeneration in chronic wounds, especially ischemic wounds.

Accelerated Wound Healing and Keratinocyte Proliferation through PI3K/Akt/pS6 and VEGFR2 Signaling by Topical Use of Pleural Fluid.

Impaired wound healing is an ongoing issue that cancer patients undergoing chemotherapy or radiotherapy face. Our previous study regarding lung-cancer-associated pleural fluid (LCPF) demonstrated its propensity to promote endothelial proliferation, migration, and angiogenesis, which are crucial features during cutaneous wound healing. Therefore, the current study aimed to investigate the effect of pleural fluid on cutaneous wound closure in vitro and in vivo using HaCaT keratinocytes and a full-thickness skin wound model, respectively. Both heart-failure-associated pleural fluid (HFPF) and LCPF were sequentially centrifuged and filtered to obtain a cell-free status. Treatment with HFPF and LCPF homogeneously induced HaCaT proliferation with cell cycle progression, migration, and MMP2 upregulation. Western blotting revealed increased PI3K/Akt phosphorylation and VEGFR2/VEGFA expression in HaCaT cells. When treated with the PI3K inhibitor, LCPF-induced keratinocyte proliferation was attenuated with decreased pS6 levels. By applying the VEGFR2 inhibitor, LCPF-induced keratinocyte proliferation was ameliorated by pS6 and MMP2 downregulation. The effect of LCPF-induced cell junction rearrangement was disrupted by co-treatment with a VEGFR2 inhibitor. Compared with a 0.9% saline dressing, LCPF significantly accelerated wound closure and re-epithelization when used as a dressing material in a full-thickness wound model. Histological analysis revealed increased neo-epidermis thickness and dermis collagen synthesis in the LCPF-treated group. Furthermore, LCPF treatment activated basal keratinocytes at the wound edge with the upregulation of Ki-67, VEGFA, and MMP2. Our preliminaries provided the benefit of wet dressing with pleural fluid to improve cutaneous wound closure through enhanced re-epithelization and disclosed future autologous application in cancer wound treatment.

Transplantation of decellularised human amniotic membranes seeded with mesenchymal stem cell-educated macrophages into animal models.

The reconstruction of chronic skin wounds remains a public health challenge in dermatology. Precisely controlling and monitoring the wound-healing process should result in enhanced outcomes for the patient. Cell-based therapies have shown great potential in medicine due to their immunomodulatory and healing properties. Herein, we produced activated macrophages by treating circulating monocytes with mesenchymal stem cell (MSC) supernatant. We also demonstrated the critical role of activated macrophages transplantation using amniotic membranes in accelerating wound healing in an animal wound model. The activated macrophages not only exhibited immunomodulatory cytokines like transforming growth factorβ (TGFβ) and interleukin 10 (and IL10) secretion but also showed attachment and proliferation ability on the amniotic membrane scaffold. Moreover, MSCs supernatant-treated cells also displayed significant ARG1, CD206, and IL 10 genes expression. Inspired by the in vitro results, we examined the in vivo therapeutic efficacy of the activated macrophage transplantation using an acellular amniotic membrane carrier in a full-thickness cutaneous wound model. The wound healing rate was significant in the group treated with macrophages generated via mesenchymal cell therapy seeded human amniotic membrane. There was less scarring in the wound sites after placing cell-scaffold constructs in the wound sites in the animal models. Overall, macrophages stimulated with mesenchymal cells' supernatant exhibited improved healing processes in incisional wounds by decreasing the inflammatory phase, increasing angiogenesis, and reducing scar tissue development.

Three-dimensional cultivation of human adipose-derived stem cells with human decellularized adipose tissue matrix scaffold promotes diabetic wound healing

Diabetic wounds are a worldwide health problem, with increasing morbidity and risk of amputation. This study investigated a novel application of a human decellularized adipose tissue matrix (hDAM) as a natural 3D scaffold for delivering human adipose-derived stem cells (hASCs) to diabetic wounds. The porous structure, ability to preserve extracellular matrix components, and convenient storage conditions of decellularized hDAM make it a potential clinical wound dressing material. The hASCs cultured in the hDAM scaffold exhibited a fibroblast-like morphology and more evenly distributed cells on both the surface and inside the porous structure of the hDAM scaffold. In addition, the biocompatibility of hDAM enhanced the hASCs proliferation, maintenance of the stemness properties, and release of angiogenic cytokines compared to those under standard culture conditions. Moreover, cell suspensions derived from hASCs cultured in hDAM scaffolds promoted the proliferation and migration of human umbilical vascular endothelial cells, indicating its potential effect in promoting angiogenesis. Furthermore, the potential clinical therapeutic efficacy of the hASC-hDAM composite for diabetic wound healing was evaluated using a full-thickness wound model in diabetic mice. Diabetic rats treated with the hASCs-seeded hDAM scaffold displayed enhanced wound healing efficiency, including an improved blood perfusion volume for wounds, reduced number of inflammatory cells, and enhanced epithelization. This study demonstrated that the 3D model that combined hASCs and an hDAM could accelerate wound healing and might hold potential for clinical application to enhance diabetic wound healing and regeneration.

Mesenchymal Stem Cells From Mouse Hair Follicles Reduce Hypertrophic Scarring in a Murine Wound Healing Model

Wound healing of acute full-thickness injuries and chronic non-healing ulcers leads to delayed wound closure, prolonged recovery period and hypertrophic scarring, generating a demand for an autologous cell therapy and a relevant pre-clinical research models for wound healing. In this study, an immunocompetent model for wound healing was employed using a syngeneic murine cell line of mesenchymal stem cells cultured from the mouse whisker hair follicle outer root sheath (named moMSCORS). moMSCORS were isolated using an air-liquid interface method, expanded in vitro and characterized according to the MSC definition criteria - cell viability, in vitro proliferation, MSC phenotype and multi-lineage differentiations. Moreover, upon applying moMSCORS in an in vivo full-thickness wound model in the syngeneic C57BL/6 mice, the treated wounds displayed different morphology to that of the untreated wound beds. Quantitative evaluation of angiogenesis, granulation and wound closure involving clinical scoring and software-based quantification indicated a lower degree of inflammation in the treated wounds. Histological staining of treated wounds by the means of H&E, Alcian Blue, PicroSirius Red and αSMA immune labelling showed lower cellularity, less collagen filaments as well as thinner dermal and epidermal layers compared with the untreated wounds, indicating a general reduction of hypertrophic scars. The decreased inflammation, accelerated wound closure and non-hypertrophic scarring, which were facilitated by moMSCORS, hereby address a common problem of hypertrophic scars and non-physiological tissue properties upon wound closure, and additionally offer an in vivo model for the autologous cell-based wound healing.Graphic

Adipose-Derived Stem Cell Conditioned Medium and Wound Healing: A Systematic Review.

Adipose-derived stem cells (ASCs) have been growing in popularity for their potential in wound healing and tissue engineering. Stem cell therapies are limited in application, with the need to maintain cell viability and function as well as safety concerns. It has been increasingly reported that the effects of ASCs are predominantly attributable to the paracrine effects of the secreted factors, which can be collected in conditioned medium (CM). The goal of this systematic review was to investigate the effects on wound healing of CM collected from ASC culture. Original articles relevant to ASC-CM and wound healing (in vitro: dermal fibroblast, epidermal keratinocytes, and their equivalent cell lines; in vivo: full-thickness wound models) were included. The agreement level of selections between two investigators was calculated by the kappa scores. And the information concerning to the publications, CM preparation, and its application and effects was extracted and reported in a systematic way and summarized in tables. In total, 121 publications were initially identified through a search of the PubMed/MEDLINE database with a specific search algorithm, and 36 articles were ultimately included after 2 screenings. Nineteen were in vitro studies that met the search criteria and 17 were in vivo studies with or without in vitro data. In summary, based on the included articles, treatment with ASC-CM, to a large extent, resulted in positive effects on wound healing in vitro and in vivo. Modulation of the culture conditions of ASCs producing the CM, including hypoxic conditions, alternative substrates, medium supplementation, as well as genetic modification of cells, favorably promoted the effects of ASC-CM. Finally, a discussion of the future perspectives and therapeutic potential of ASC-CM, which also addresses the limitations of the field, is presented. A limitation of the evidence is the inconsistency in CM preparation methods among included articles. In conclusion, ASC-CM is a promising novel cell-free therapy for wound healing in regenerative medicine and warrants further exploration. Impact Statement This systematic review researched in vitro and in vivo studies regarding therapeutic effects of adipose-derived stem cell (ASC) conditioned medium (CM) on wound healing, generally indicating favorable effects. ASC-CM can avoid safety concerns accompanying stem cell therapies and reduce the cost of treatment. Modulation in the process of ASC culture and CM preparation may promote its therapeutic potential. The limitation and future perspectives of the field of ASC-CM therapy were also presented. ASC-CM may be useful to its future application for a wide range of clinical targets including inflammatory and ischemic diseases.

Apoptotic bodies extracted from adipose mesenchymal stem cells carry microRNA-21–5p to induce M2 polarization of macrophages and augment skin wound healing by targeting KLF6

BackgroundAdipose-derived mesenchymal stem cells (adMSCs) are suggested as potential tools for the treatment of regenerative diseases, including tissue repair. This study aimed to explore the function of adMSC-derived apoptotic bodies in skin wound healing and the molecules of action. MethodsThe acquired adMSCs and their-derived apoptotic bodies were identified. A murine model of full-thickness skin wounds was treated with apoptotic bodies. The wound healing process of mice and the pathological changes in wound tissues were examined. Ana-1 macrophages were treated with lipopolysaccharide (LPS) and apoptotic bodies for in vitro experiments. Polarization of macrophages was examined by immunofluorescence staining of the specific biomarkers and ELISA kits. Dermal microvascular endothelial cells (DMECs) or dermal fibroblasts (DFs) were co-cultured with apoptotic bodies or the LPS- and apoptotic bodies-treated Ana-1 cells. Downstream molecules mediated by apoptotic bodies were screened by microarray and bioinformatic analyses. ResultsApoptotic bodies treatment accelerated skin wound healing in mice and promoted formation of granulation tissues and blood vessels in wound tissues. Apoptotic bodies treatment induced M2 polarization of macrophages. The angiogenesis ability of DMECs, and the viability and migration of DFs were increased when co-cultured with the apoptotic bodies-treated Ana-1 cells. MicroRNA (miR)-21–5p was abundantly expressed in ABs, and kruppel like factor 6 (KLF6) mRNA was confirmed as a target of miR-21–5p. Overexpression of KLF6 reduced M2 polarization of macrophages and blocked the promoting effect of apoptotic bodies on wound healing in vitro and in vivo. ConclusionmiR-21–5p carried by adMSC-derived apoptotic bodies targets KLF6 to induce M2 polarization of macrophages and augment skin wound healing.

Mussel-inspired adhesive gelatin-polyacrylamide hydrogel wound dressing loaded with tetracycline hydrochloride to enhance complete skin regeneration.

Even though the global wound care market size was valued at USD 19.83 billion in 2020, it is still a challenge to develop a hydrogel-based wound dressing with a good mechanical property, adhesiveness and antibacterial property. This study established and validated a mussel-inspired adhesive hydrogel wound dressing with antibacterial activity by dispersing tetracycline hydrochloride into hydrogel based polydopamine, gelatin and polyacrylamide. A tough hydrogel with a fracture stress of 0.42 MPa was prepared by changing the contents of the gelatin and polyacrylamide. With the addition of polydopamine and tetracycline hydrochloride, the hydrogel was endowed with an adhesive property (with a tissue adhesive strength of 4.13 kPa) and antibacterial activity against both Escherichia coli and Staphylococcus aureus. Finally, a rat full-thickness skin defect wound model was used to evaluate the performance of the hydrogels in wound repair. The hydrogel group showed a significantly reduced wound area (95.72%) compared with the blank group (86.34%) on day 14. The hydrogel promoted the collagen deposition, weakened the inflammatory response and enhanced wound healing. Therefore, the hydrogel with multifunctional properties is a promising candidate for complete skin regeneration.

Preparation and properties of N-glycosylated chitosan/polyvinyl alcohol hydrogels for use in wound dressings.

Chitosan and its derivatives show potent biocompatibility, biodegradability, antimicrobial activity, hemostatic effects, and wound healing properties. Their application in wound dressings has garnered substantial research interest. In this work, we prepared a drug-loaded hydrogel by mixing N-glycosylated chitosan with polyvinyl alcohol (PVA), followed by loading of ofloxacin. A 2:1 volume ratio of chitosan to PVA was found to be optimal based on swelling and water evaporation rates. The slow-drug-release performance of the blended hydrogel was best when the ofloxacin loading was 5.0%. The ofloxacin-loaded hydrogel shows excellent antimicrobial properties in vitro and wound healing ability in an in vivo rabbit full-thickness excision wound model. The chitosan/PVA blended hydrogel has great potential for use in wound dressings and sustained drug release.

M2 Macrophage-Derived Concentrated Conditioned Media Significantly Improves Skin Wound Healing.

Macrophages, with many different phenotypes play a major role during wound healing process, secreting the cytokines crucial to angiogenesis, cell recruitment and ECM remodeling. Therefore, macrophage-derived cytokines may be attractive therapeutic resource for wound healing. To obtain a conditioned media (CM) from macrophages, human monocyte THP-1 cells were seeded on TCP or human fibroblast-derived matrix (hFDM) and they were differentiated into M1 or M2 phenotype using distinct protocols. A combination of different substrates and macrophage phenotypes produced M1- and M2-CM or M1-hFDM- and M2-hFDM-CM, respectively. Proteome microarray determines the cytokine contents in those CMs. CMs-treated human dermal fibroblast (hDFB) was analyzed using collagen synthesis and wound scratch assay. Concentrated form of the CM (CCM), obtained by high-speed centrifugation, was administered to a murine full-thickness wound model using alginate patch, where alginate patch was incubated in the M2-CCM overnight at 4°C before transplantation. On 14day post-treatment, examination was carried out through H&E and Herovici staining. Keratinocyte and M2 macrophages were also evaluated via immunofluorescence staining. Cytokine analysis of CMs found CCL1, CCL5, and G-CSF, where CCL5 is more dominant. We found increased collagen synthesis and faster wound closure in hDFB treated with M2-CM. Full-thickness wounds treated by M2-hFDM-CCM containing alginate patch showed early wound closure, larger blood vessels, increased mature collagen deposition, enhanced keratinocyte maturation and more M2-macrophage population. Our study demonstrated therapeutic potential of the CM derived from M2 macrophages, where the cytokines in the CM may have played an active role for enhanced wound healing.

Nano-Sized Extracellular Matrix Particles Lead to Therapeutic Improvement for Cutaneous Wound and Hindlimb Ischemia.

Cell-derived matrix (CDM) has proven its therapeutic potential and been utilized as a promising resource in tissue regeneration. In this study, we prepared a human fibroblast-derived matrix (FDM) by decellularization of in vitro cultured cells and transformed the FDM into a nano-sized suspended formulation (sFDM) using ultrasonication. The sFDM was then homogeneously mixed with Pluronic F127 and hyaluronic acid (HA), to effectively administer sFDM into target sites. Both sFDM and sFDM containing hydrogel (PH/sFDM) were characterized via immunofluorescence, sol–gel transition, rheological analysis, and biochemical factors array. We found that PH/sFDM hydrogel has biocompatible, mechanically stable, injectable properties and can be easily administered into the external and internal target regions. sFDM itself holds diverse bioactive molecules. Interestingly, sFDM-containing serum-free media helped maintain the metabolic activity of endothelial cells significantly better than those in serum-free condition. PH/sFDM also promoted vascular endothelial growth factor (VEGF) secretion from monocytes in vitro. Moreover, when we evaluated therapeutic effects of PH/sFDM via the murine full-thickness skin wound model, regenerative potential of PH/sFDM was supported by epidermal thickness, significantly more neovessel formation, and enhanced mature collagen deposition. The hindlimb ischemia model also found some therapeutic improvements, as assessed by accelerated blood reperfusion and substantially diminished necrosis and fibrosis in the gastrocnemius and tibialis muscles. Together, based on sFDM holding a strong therapeutic potential, our engineered hydrogel (PH/sFDM) should be a promising candidate in tissue engineering and regenerative medicine.

Studying the in vivo application of a liquid dermal scaffold in promoting wound healing in a mouse model.

Lack of matrix deposition is one of the main factors that complicates the healing process of wounds. The aim of this study was to test the efficacy and safety of a liquid dermal scaffold, referred to as MeshFill (MF) that can fill the complex network of tunnels and cavities which are usually found in chronic wounds and hence improve the healing process. We evaluated in vitro and in vivo properties of a novel liquid dermal scaffold in a delayed murine full-thickness wound model. We also compared this scaffold with two commercially available granular collagen-based products (GCBP). Liquid dermal scaffold accelerated wound closure significantly compared with no-treated control and collagen-based injectable composites in a delayed splinted wound model. When we compared cellular composition and count between MF, no treatment and GCBP at the histology level, it was found that MF was the most analogous and consistent with the normal anatomy of the skin. These findings were matched with the clinical outcome observation. The flowable in situ forming scaffold is liquid at cold temperature and gels after application to the wound site. Therefore, it would conform to the topography of the wound when liquid and provides adequate tensile strength when solidified. This patient-ready gelling dermal scaffold also contains the nutritional ingredients and therefore supports cell growth. Applying an injectable liquid scaffold that can fill wound gaps and generate a matrix to promote keratinocytes and fibroblasts migration, can result in improvement of the healing process of complex wounds.

Controlled pVEGF delivery via a gene-activated matrix comprised of a peptide-modified non-viral vector and a nanofibrous scaffold for skin wound healing

Regulating cell function and tissue formation by combining gene delivery with functional scaffolds to create gene-activated matrices (GAMs) is a promising strategy for tissue engineering. However, fabrication of GAMs with low cytotoxicity, high transfection efficiency, and long-term gene delivery properties remains a challenge. In this study, a non-viral DNA delivery nanocomplex was developed by modifying poly (D, L-lactic-co-glycolic acid)/polyethylenimine (PLGA/PEI) nanoparticles with the cell-penetrating peptide KALA. Subsequently, the nanocomplex carrying plasmid DNA encoding vascular endothelial growth factor (pVEGF) was immobilized onto a polydopamine-coated electrospun alginate nanofibrous scaffold, resulting in a GAM for enhanced skin wound healing. The nanocomplex exhibited much lower cytotoxicity and comparable or even higher transfection efficiency compared with PEI. The GAM enabled sustained gene release and long-tern transgene expression of VEGF in vitro. In an excisional full-thickness skin wound rat model, the GAM could accelerate wound closure, promote complete re-epithelization, reduce inflammatory response, and enhance neovascularization, ultimately enhancing skin wound healing. The current GAM comprising a low-toxic gene delivery nanocomplex and a biocompatible 3D nanofibrous scaffold demonstrates great potential for mediating long-term cell functions and may become a powerful tool for gene delivery in tissue engineering. Statement of significanceGene delivery is a promising strategy in promoting tissue regeneration as an effective alternative to growth factor delivery, but the study on three-dimensional gene-activated scaffolds remains in its infancy. Herein, a biodegradable nanofibrous gene-activated matrix integrating non-viral nanoparticle vector was designed and evaluated both in vitro and in vivo. The results show that the nanoparticle vector provided high transfection efficiency with minimal cytotoxicity. After surface immobilization of the nanocomplexes carrying plasmid DNA encoding vascular endothelial growth factor (pVEGF), the nanofibrous scaffold enabled sustained DNA release and long-term transgene expression in vitro. In a rat full-thickness skin wound model, the scaffold could accelerate wound healing. This innovative gene-activated matrix can be a promising candidate for tissue regeneration.

Injectable hydrogel for postoperative synergistic photothermal-chemodynamic tumor and anti-infection therapy

Tumor surgery is usually accompanied by neoplasm residual, tissue defects, and multi-drug resistant bacterial infection, causing high tumor recurrence, low survival rate, and chronic wounds. Herein, a light-activated injectable hydrogel based on bioactive nanocomposite system is developed by incorporating Ag2S nanodots conjugated Fe-doped bioactive glass nanoparticles (BGN-Fe-Ag2S) into biodegradable PEGDA and AIPH solution for inhibiting tumor growth, treating bacterial infection, and promoting wound healing. Under laser irradiation, the photothermal effect mediated by Ag2S nanodots would trigger the decomposition of AIPH, generating alkyl radicals to initiate the gelation of PEGDA. The in-situ gelatinized hydrogel, with outstanding photothermal effect and chemodynamic effect derived from the doped Fe in BGN-Fe-Ag2S, can not only eliminate multidrug-resistant bacteria but also efficiently ablated tumor during treatment. Moreover, the hydrogel significantly accelerated wound healing with more skin appendages in the full-thickness cutaneous wounds model because of the hydrolysis of bioactive glass. These results manifest that this multifunctional hydrogel is a suitable biomaterial to inhibit tumor proliferation and overcome tissue bacterial infection after surgical removal of tumors.

One-Step Synthesis of Multifunctional Chitosan Hydrogel for Full-Thickness Wound Closure and Healing.

Multifunctional hydrogel as a sealant or wound dressing with high adhesiveness and excellent antibacterial activity is highly desirable in clinical applications. In this contribution, one-step synthetic hydrogel based on quaternized chitosan (QCS), tannic acid (TA), and ferric iron (Fe(III)) is developed for skin incision closure and Staphylococcus aureus (S. aureus)-infected wound healing. In this hydrogel system, the ionic bonds and hydrogen bonds between QCS and TA form the main backbone of hydrogel, the metal coordination bonds between TA and Fe(III) (catechol-Fe) endow hydrogel with excellent adhesiveness and (near-infrared light) NIR-responsive photothermal property, and these multiple dynamic physical crosslinks enable QCS/TA/Fe hydrogel with flexible self-healing ability and injectability. Moreover, QCS/TA/Fe hydrogel possesses superior antioxidant, anti-inflammatory, hemostasis, and biocompatibility. Also, it is safe for vital organs. The data from the mouse skin incision model and infected full-thickness skin wound model presented the high wound closure effectiveness and acceleration of the wound healing process by this multifunctional hydrogel, highlighting its great potential in wound management.

Accelerating skin barrier repair using novel bioactive magnesium-doped nanofibers of non-mulberry silk fibroin during wound healing

Novel magnesium doped non-mulberry silk fibroin nanofibers with ability to enhance skin barrier function were successfully fabricated using electrospinning technique for wound healing applications. Magnesium nanoparticles incorporated in the electrospun nanofibers releases Mg2+ ions at the site of implementation. The effect of Mg2+ is of considerable concern in wound healing due to its skin barrier repair ability and its role in blood coagulation. The physicochemical characterization of the scaffold was investigated by determining the morphology and secondary structure confirmation. The effects of Mg2+ ions in silk fibroin microenvironment have been evaluated using SEM, XRD, and FTIR to confirm the incorporation of magnesium in the film. The aim of this study is to see the effect of doped Mg on the structural, physical, and biological properties of non-mulberry silk fibroin (NSF) film. The magnesium doped nanofibrous film exhibited enhanced mechanical property, satisfactory blood clotting ability, and good in vitro degradability. This silk fibroin-based film mimicking extracellular matrix for skin regeneration were constructed using electrospinning technique. The wound healing efficiency of prepared nanofibers were evaluated in full-thickness wound models of rat. The Mg doped silk fibroin film exhibited faster wound healing activity (14 days) among all experimental group. The study indicates the potential of magnesium-doped silk /PVA film as skin substitute film.

VEGF loaded porcine decellularized adipose tissue derived hydrogel could enhance angiogenesis in vitro and in vivo

Decellularized adipose tissue (DAT) has been widely applied in soft tissue regeneration, however, DAT may play a promising role in accelerating wound healing because of suitable physical characteristics and biological properties. In this research, we fabricated the DAT hydrogel and the VEGF loaded heparinized-DAT hydrogel (VEGF hydrogel) and evaluated their efficiency in full-thickness skin wound model. We designed one method to encapsulate VEGF to hep-DAT hydrogel in order to control VEGF release rate. Result showed that the VEGF release could last up to 3 day, and 1 ml hep-DAT hydrogel (5 mg/ml) could bind up to (64.521 ± 11.550) ng VEGF which was 4.2 times to that of DAT hydrogels. Moreover, the VEGF released in 3 days still preserved biological activities that the released VEGF could enhance tube formation of HUVECs in vitro. Otherwise, the VEGF hydrogel could significantly accelerate wound healing compared with DAT hydrogel and VEGF injection, collagen deposition and newly formed vessels in the VEGF hydrogel groups were also higher than those of other groups. We believed that the VEGF hydrogel could be one attractive biomaterial for potential clinical applications.