Activation of the BMP2/SMAD4 signaling pathway for enhancing articular cartilage regeneration of mesenchymal stem cells utilizing chitosan/alginate nanoparticles on 3D extracellular matrix scaffold.

This study investigated the efficacy of using chitosan/alginate nanoparticles loaded with recombinant human bone morphogenetic-2 (rhBMP-2) and SMAD4 encoding plasmid to enhance the chondrogenesis of human bone marrow mesenchymal stem cells (hBM-MSCs) seeded on an extracellular matrix (ECM). The research treatments included the stem cells treated with the biological cocktail (BC), negative control (NC), hBM-MSCs with chondrogenic medium (MCM), hBM-MSCs with naked rhBMP-2 and chondrogenic medium (NB/C), and hBM-MSCs with naked rhBMP-2 and chondrogenic medium plus SMAD4 encoding plasmid transfected with polyethyleneimine (PEI) (NB/C/S/P). The cartilage differentiation was performed with real-time quantitative PCR analysis and alizarin blue staining. The data indicated that the biological cocktail (BC) exhibited significantly higher expression of cartilage-related genes compared to significant differences with MCM and negative control (NC) on chondrogenesis. In the (NB/C/S/P), the expression levels of SOX9 and COLX were lower than those in the BC group. The expression pattern of the ACAN gene was similar to COL2A1 changes suggesting that it holds promising potential for cartilage regeneration.

Skin Tissue Engineering Advances in Burns: A Brief Introduction to the Past, the Present, and the Future Potential.

Burn injuries are a severe form of skin damage with a significant risk of scarring and systemic sequelae. Approximately 11 million individuals worldwide suffer burn injuries annually, with 180,000 people dying due to their injuries. Wound healing is considered the main determinant for the survival of severe burns and remains a challenge. The surgical treatment of burn wounds entails debridement of necrotic tissue, and the wound is covered with autologous skin substitutes taken from healthy donor areas. Autologous skin transplantation is still considered to be the gold standard for wound repair. However, autologous skin grafts are not always possible, especially in cases with extensive burns and limited donor sites. Allografts from human cadaver skin and xenografts from pig skin may be used in these situations to cover the wounds temporarily. Alternatively, dermal analogs are used until permanent coverage with autologous skin grafts or artificial skins can be achieved, requiring staged procedures to prolong the healing times with the associated risks of local and systemic infection. Over the last few decades, the wound healing process through tissue-engineered skin substitutes has significantly enhanced as the advances in intensive care ensuring early survival have led to the need to repair large skin defects. The focus has shifted from survival to the quality of survival, necessitating accelerated wound repair. This special volume of JBCR is dedicated to the discoveries, developments, and applications leading the reader into the past, present, and future perspectives of skin tissue engineering in burn injuries.

PVA-Based Nanofibers Containing Chitosan Modified with Graphene Oxide and Carbon Quantum Dot-Doped TiO2 Enhance Wound Healing in a Rat Model.

Electrospun nanofibrous constructs based on nanoparticles and biopolymers have recently been used in tissue engineering because of their similarity to the extracellular matrix in nature. In this study, electrospun chitosan-carbon quantum dot-titanium dioxide-graphene oxide (CS-CQD-TiO2-GO) nanofibrous mats were synthesized for use as wound dressings by the electrospinning method. To increase the biodegradation rate and water resistance, the fabricated nanofibrous mats were cross-linked. SEM images showed a uniform and coherent structure of CS-CQD-TiO2-GO nanocomposites and CS-CQD-TiO2-GO electrospun nanofibers mats. FTIR analysis, XRD pattern, SEM mapping, and EDS spectrum demonstrate the accuracy of the synthesis as well as the elemental and chemical structure of the nanofibrous mat. The water contact angle indicated that the nanofibrous mat had a hydrophilic property, which is essential for controlling wound exudates. The tensile strength and elongation tests showed that the nanofibrous mat has suitable mechanical properties for wound dressing, including significant flexibility and strength. Interestingly, antimicrobial testing illustrated that the fabricated nanofibrous mat had antibacterial activity against Gram-negative and Gram-positive bacteria. Appropriate cell viability and cytocompatibility of treated mouse fibroblast NIH3T3 cells with the nanofibrous mat were determined using an MTT assay. The animal study results confirmed the proper potential of the nanofibrous mat in wound dressing applications.

In vitro and in vivo evaluation of a nanofiber wound dressing loaded with melatonin.

Wound healing is a complicated process that takes a long time to complete. The three-layer nanofiber wound dressing containing melatonin is highly expected to show remarkable wound repair by reducing the wound healing time. In this study, chitosan (Cs)-polycaprolactone (PCL)/ polyvinylalcohol (PVA)-melatonin (MEL)/ chitosan-polycaprolactone three-layer nanofiber wound dressing was prepared by electrospinning for melatonin sustained release. The characteristics of the wound dressing were further evaluated. The wound dressing had a high water uptake after 24 h (401%), and the water contact angle results showed that it had hydrophilicity effect that supported the cell attachment. The wound healing effect of wound dressing was examined using a full-thickness excisional model of rat skin by the local administration of MEL. The gene expressions of transforming growth factor-beta (TGF-ß1), alpha-smooth muscle actin (α-SMA), collagen type I (COL1A1), and collagen type III (COL3A1) were further studied. The histopathological evaluation showed the complete regeneration of the epithelial layer, remodeling of wounds, collagen synthesis, and reduction in inflammatory cells. The NF + 20% MEL significantly increased TGF-ß1, COL1A1, COL3A1, and α-SMA mRNA expressions. This wound dressing may have a considerable potential as a wound dressing to accelerate the wound healing.

Synthesis of PLGA/chitosan/zeolites and PLGA/chitosan/metal organic frameworks nanofibers for targeted delivery of Paclitaxel toward prostate cancer cells death.

In the present study, the various zeolites including hydrophilic Y zeolite, hydrophobic ZSM-5 zeolite and metal organic frameworks (MOFs) including MIL-101 and ZIF-8 were incorporated into the PLGA/chitosan nanofibers for controlled release of Paclitaxel anticancer drug against prostate cancer in vitro and in vivo. The synthesized nanoparticles and nanofibers were characterized using FTIR, XRD, SEM, BET and water contact angle analysis. The drug loading efficiency of nanofibers containing zeolites and MOFs indicated that the MOFs were more useful compared with zeolites for higher loading of Paclitaxel molecules. The Paclitaxel release behavior from nanofibers containing zeolites and MOFs were also examined. The MTT assay and DAPI staining analysis were used to determine the cytotoxicity and apoptosis effect of nanofibers containing Paclitaxel against LNCaP prostate cancer cell lines. The tumor inhibition rate in vivo was carried out to obtain the optimum nanofibrous formulation with maximum cell death percentage and tumor inhibition rate. The obtained results revealed the better activity of MOFs compared nanozeolites for higher loading of Paclitaxel drug into the nanoparticles and a more sustained release of drug from nanofibers containing MOFs.

Design, fabrication, and optimization of a dual function three-layer scaffold for controlled release of metformin hydrochloride to alleviate fibrosis and accelerate wound healing.

Abnormal wound healing caused by the over-expression of collagen and fibronectin leads to fibrosis, the major complication of all treatment modalities. A three-layer nanofiber scaffold was designed, optimized, and fabricated. This scaffold comprised two supportive polycaprolactone (PCL)-chitosan layers on the sides and a polyvinyl alcohol (PVA)-metformin hydrochloride (metformin-HCl) in the middle. The physico-chemical properties of scaffold, such as mechanical characteristics, degradation, swelling, and in-vitro drug release, were evaluated. The biological tests, including cell viability in response to metformin-HCl and Tween 80, scaffold biocompatibility, cell attachment, and antibacterial activity, were further conducted. The wound healing effect of scaffold loaded with metformin-HCl (MSc+Met) was assessed in donut-shaped silicone splints in rats. Histopathological and immunohistochemical evaluation as well as mRNA expression levels of fibrosis markers were also studied. SEM images indicated a uniform, bead-less morphology and high porosity. Surface modification of scaffold by Tween 80 improved the surface hydrophilicity and enhanced the adhesion and proliferation of fibroblasts. The scar area on day 15 in MSc+Met was significantly lower than that of other groups. Histopathological and immunohistochemical evaluation revealed that group MSc+Met was the best, having significantly lower inflammation, higher angiogenesis, the smallest scar width and depth, maximum epitheliogenesis score, and the most optimal modulation of collagen density. Local administration of metformin-HCl substantially down-regulated the expression of fibrosis-involved genes: transforming growth factor (TGF-ß1), collagen type 1 (Col-I), fibronectin, collagen type 3 (Col-III), and alpha-smooth muscle actin (α-SMA). Inhibiting these genes alleviates scar formation but delays wound healing; thus, an engineered scaffold was used to prevent delay in wound healing. These results provided evidence for the first time to introduce an anti-fibrogenic slow-releasing scaffold, which acts in a dual role, both alleviating fibrosis and accelerating wound healing.

UiO-66 metal organic framework nanoparticles loaded carboxymethyl chitosan/poly ethylene oxide/polyurethane core-shell nanofibers for controlled release of doxorubicin and folic acid.

Doxorubicin (DOX) and folic acid (FA) were incorporated into the UiO-66 metal organic framework (MOF) and following were loaded into the carboxymethyl chitosan/poly ethylene oxide (PEO)/polyurethane core-shell nanofibers for controlled release of DOX and FA toward MCF-7 cells death. The synthesized nanocarriers were characterized using TEM, XRD, and SEM analysis. The drug loading efficiency and release profiles of DOX/MOF and FA/MOF from synthesized nanofibers have been investigated. The fitting of kinetic data by the pharmacokinetic models demonstrated the non-Fickian diffusion from nanofibers and Fickian diffusion from core-shell fibers. The cytotoxicity of synthesized nanofibers toward MCF-7 cancer cells was evaluated using DAPI staining, MTT assay and flow cytometry tests to investigate the simultaneous use of DOX and FA in the nanofibrous matrix for MCF-7 cells death in vitro. The maximum cell death using DOX-FA loaded-core-shell fibers produced by coaxial electrospinning method under 0.3, 0.5 and 0.8 mLh-1 shell flow rates were found to be 82 ± 0.7, 83 ± 0.5 and 87 ± 0.5% after 168, 240 and 240 h, respectively. The cytotoxicity results indicated that the co-delivery of DOX and FA into the core-shell fibers could be widely used for various cancers treatment.

Synthesis and evaluation of injectable thermosensitive penta-block copolymer hydrogel (PNIPAAm-PCL-PEG-PCL-PNIPAAm) and star-shaped poly(CL─CO─LA)-b-PEG for wound healing applications.

BACKGROUND: Loss of skin integrity due to injury, burning, or illness makes the development of new treatment options necessary. Skin tissue engineering provides some solutions for these problems. OBJECTIVE: The potential of a biodegradable star-shaped copolymer [Poly(CL─CO─LA)-b-PEG] and penta-block copolymer hydrogel (PNIPAAm-PCL-PEG-PCL-PNIPAAm) was assessed for skin tissue engineering applications. METHODS: Two copolymers were synthesized for cellular culture scaffolds and their mechanical properties were compared. The resulting star-shaped copolymer and thermosensitive penta-block copolymer were characterized using Fourier transform infrared and nuclear magnetic resonance spectroscopy. The crystallizability of the two copolymers was analyzed using X-ray diffraction. The resulting thermosensitive penta-block copolymer was evaluated by differential thermal analysis, differential scanning calorimetry and thermogravimetric analysis. Scanning electron microscopy and in vitro degradation of the polymer network in phosphate buffer solutions (pH 7.4) at 37°C were also examined. The pore size of the gels was calculated with Image Analyzer software. Finally, the cytotoxic, morphological, and gene expression effects of copolymers on the skin fibroblast were evaluated. RESULTS: The experiments showed that the PNIPAAm-PCL-PEG-PCL-PNIPAAm polymer with the right composition and the expected molecular weight was achieved. The hydrogel had less crystallizability compared with its precursors. The resulting thermosensitive hydrogel had a three-dimensional structure with interconnected pores that mimicked the extracellular matrix. The control of the degradability rate can be possible by weight percent changes. The pore size correlated with the polymer concentration in aqueous solution and the pore sizes of the 20 wt% hydrogel were better for fibroblast cultivation than those of the 10 wt% hydrogel. Cell proliferation on the 20% gel was more than that of the 10% gel. The hydrogel not only preserved the viability and phenotypical morphology of the entrapped cells but also stimulated the initial cell-cell interactions and proliferation of fibroblasts. The hydrogel did not influence cell conformation and this property of the polymer underlined its safety. Cells seeded on this copolymer showed a normal and spear shape and formed a focal adhesion with the hydrogel surface. Notably, the hydrogel increased collagen I α1 and collagen III mRNAs expression. CONCLUSION: Due to the low molecular weight and poor mechanical strength of the star-shaped copolymer, it was not considered for fabrication of the scaffolds for wound healing. The biodegradable, biocompatible, injectable and thermosensitive PNIPAAm-PCL-PEG-PCL-PNIPAAm hydrogel in 20 wt% demonstrated a desirable potential for future application as a cell scaffold in skin tissue engineering and wound healing.

Graphene oxide-l-arginine nanogel: A pH-sensitive fluorouracil nanocarrier.

Nowadays, putting forward an accurate cancer therapy method with minimal side effects is an important topic of research. Nanostructures, for their ability in controlled and targeted drug release on specific cells, are critical materials in this field. In this study, a pH-sensitive graphene oxide-l-arginine nanogel was synthesized to carry and release 5-fluorouracil. Optimized conditions using statistical analysis, based on the maximum relative viscosity of nanogel, were evaluated: 5.489 for the concentration of l-arginine and 2.404 for pH. The prepared nanogels were characterized using scanning electron microscope and transmission electron microscope images and Fourier-transform infrared spectroscopic analysis. Cytotoxicity was assessed using the sulforhodamine B (SRB) assay on MCF-7 breast cancer cells. The fluorouracil release was measured by the dialysis bag method, UV spectrophotometry, and fluorouracil calibration diagram. Results proved the successful controlled release of fluorouracil at pH 5.4 and the beneficial role of graphene-oxide- l-arginine- fluorouracil nanogel in eliminating cancer cells.