Display omitted
•A GT scaffold was constructed between substrate and polyamide layer to provide water channels.•The GT scaffold can influence the interfacial polymerization to obtain a thin ...separation layer.•The prepared TFC membrane had a high permeability and selectivity.
In order to realize energy saving and resource recovery in desalination and waste-water treatment, it is urgent to develop nanofiltration (NF) membranes with high permeability and selectivity. Therefore, many researchers devote to designing different hydrophilic polymer-interlayers for the thin-film composite (TFC) membranes, targeting to prepare NF membranes with outstanding separation performance. However, the thin polymer-interlayer (<10 nm) can only slow down the diffusion rate of aqueous monomer and affect the interfacial polymerization (IP) process, forming a thin and defect-free polyamide (PA) layer. Herein, we constructed a hydrophilic and homogeneous gelatin (GT) scaffold with a thickness of over 100 nm on polysulfone (PSF) substrate and prepared a PA separation layer by IP process to obtain a high-performance TFC based NF membrane. The scaffold can not only affect the diffusion rate of piperazing (PIP) in IP process to form a thin PA layer, but also provide additional channels for water diffusion, which would significantly improve the permeability of NF membranes. Moreover, the fabricated PA layer has a high cross-linking degree and a negative surface potential, endowing the NF membrane with a high salts rejection rate, especially for divalent anions. Hence the permeability of the resulting NF membrane (up to 16.95 ± 1.18 L m−2 h−1 bar−1) is about 2.5 times as compared with the controlled membrane, while achieving a high Na2SO4 rejection of 99.3% ± 0.2%. In addition, the coefficient of selectivity for NF membrane are 97.73 for αNaCl/Na2SO4 and 45.66 for αNaCl/MgSO4 respectively, which are several times higher than those of the controlled NF membrane. This work provides a low-cost and facile method to prepare a TFC based NF membrane with a high permeability and selectivity.
Display omitted
Skin regeneration is one of the most important issues in tissue engineering. Research on more effective biomaterials that will enhance regeneration while enabling requirements of a ...healing skin site is an important challenge in skin tissue engineering. In this study, heparin was encapsulated in Poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) which were then incorporated into Sericin/Gelatin (Ser/Gel) nanofibers during the electrospinning process in order to develop a combined system that has controlled release approach, besides the ability to help the regeneration of skin tissue by the involvement of biopolymers; gelatin, and sericin. The loading capacity and heparin encapsulation efficiency in the nanoparticles were determined as 30.04 mg/g of polymer and 60%, respectively. Cumulative release of heparin from NPs for 1 week was faster than from NPs loaded gelatin scaffolds and from dual protein (Ser/Gel) scaffolds with ratios: 1/7 and 1/2 (approximately 85%, 65%, 55%, and 40%, respectively). Sericin addition slowed down the degradation properties of the scaffold. The scaffold having a Ser/Gel ratio (1/2) was found as the most promising candidate because of its proper fiber morphology, high water retention, and low degradation degree.
Diabetes is associated with numerous complications, such as diabetic skin wounds or ulcerations. The aim of this study was to evaluate experimentally the effectiveness of applying polycaprolactone ...(PCL)‐gelatin scaffold, with or without rat CD93 hematopoietic stem cells (HSCs), in diabetic wound healing in a rat model. CD93 HSCs were aseptically isolated from rat bone marrow using fluorescent activated cell sorting (FACS) method and FACS‐SORTER. A total of 25 Wistar rats were divided into five groups including Group I (sham, nondiabetic, and wound covered only with sterile dressing), II (control, diabetic rat), III (CD93 HSCs alone), IV (PCL‐gelatin scaffold), and V (CD93 HSCs+PCL‐gelatin scaffold). Animals were killed on Days 7, 14, or 28 posttreatment and histological sections were blindly evaluated by two expert pathologists. Death‐associated protein kinase 1 (DAPK‐1) gene and vesicular endothelial growth factors (VEGF) protein expression were evaluated using reverse transcription‐polymerase chain reaction and western blot, respectively. The thickest and the thinnest epidermises microscopically were belonged to CD93+HSCs+scaffold and the control group, respectively. The growth rate of the epidermis and adnexal epithelia was the highest in both the cell and cell+scaffold groups. Evaluation of the protein expression level of VEGF indicated that the expression levels of this growth factor were the most on Day 7 posttreatment in sham, HSCs alone, and HSCs cell+scaffold groups. While the lowest expression levels of this growth factor was detected in the control and scaffold groups. The gene expression level of DAPK‐1 on Day 7 posttreatment was higher than that of the Day 14 posttreatment in all groups. The highest and lowest gene expression levels of DAPK‐1 belonged to control and sham groups, respectively. According to our findings, CD93 HSCs offer new prospects for the treatment of diabetic ulcers and concomitant application of these cells with PCL‐gelatin nanofiber scaffold significantly improves diabetic wound treatment.
Based on the findings of the present study, it can be concluded that the polycaprolactone (PCL)‐gelatin scaffold associated with CD93+HSCs could act as an appropriate tissue engineering construct in diabetic wound healing. The CD93 HSCs present adhesion, growth, and proliferation properties in the vicinity of the PCL‐gelatin nanofiber scaffold. Despite delayed wound healing in diabetic ulcer, this compound can accelerate the wound healing process of diabetic wounds in rat. This property is due to the stimulation of vesicular endothelial growth factors secretion at the wound site as well as stimulation of angiogenesis for early regeneration, higher collagenization rate, epidermis formation, and thickening of the dermis in less time. Moreover, it is associated with the further growth of hair follicles at the site of the healed wound. Meanwhile, the results of this study confirmed the presence of CD93 HSCs at the wound site, even after 28 days of transplantation. This study also demonstrated that death‐associated protein kinase 1 gene plays an inhibitory role in the diabetic wound healing process.
•Silk/gelatin scaffold has been effective microenvironment in differentiation WJ-MSCs to IPCs.•Expression of pancreatic genes in 3D culture, increased significantly compared to the 2D ...culture.•Expression of insulin protein in 3D culture, increased significantly compared to the 2D culture.•The secretion of insulin and C-peptide in the 3D cutture was significantly higher than in 2D culture.
The use of umbilical cord-derived mesenchymal stem cells along with three-dimensional (3D) scaffolds in pancreatic tissue engineering can be considered as a treatment for diabetes. This study aimed to investigate the differentiation of Wharton’s jelly-derived mesenchymal stem cells (WJ-MSCs) into pancreatic islet-insulin producing cells (IPCs) on silk/gelatin nanofibers as a 3D scaffold. Mesenchymal markers were evaluated at the mesenchymal stem cells (MSCs) level by flow cytometry. WJ-MSCs were then cultured on 3D scaffolds and treated with a differential medium. Immunocytochemical assays showed efficient differentiation of WJ-MSCs into IPCs. Also, Real-time PCR results showed a significant increase in the expression of pancreatic genes in the 3D culture group compared to the two-dimensional (2D) culture group. Despite these cases, the secretion of insulin and C-peptide in response to different concentrations of glucose in the 3D group was significantly higher than in the 2D culture. The results of our study showed that silk/gelatin scaffold with WJ-MSCs could be a good option in the production of IPCs in regenerative medicine and pancreatic tissue engineering.
Background: Biodegradable thermosensitive hydrogel scaffolds based on novel three-block PCL-PEG-PCL and penta block PNIPAAm-PCL-PEG-PCL-PNIPAAm copolymers blended with gelatin were prepared and ...examined on functional behavior of chondrocytes. Methods: In this work, we compared two different thermosensitive hydrogel scaffolds (PNIPAAm-PCL-PEG-PCL-PNIPAAm)/Gelatin and (PCL-PEG-PCL)/Gelatin prepared by TIPS (thermally induced phase separation) method. The feature of copolymers was characterized by FT-IR, 1H NMR. The lower critical solution temperatures (LCSTs) of aqueous solutions of copolymers were measured by cloud point (turbidity) measurements. We also examined water absorption capacity and swelling ratio. Mechanical features of the prepared hydrogels were evaluated by stress-strain measurements. Thereafter, isolated chondrocytes were cultured on each scaffold for a period of 10 days and cell arrangement and morphology studied pre-and post-plating. Cell survival assay was done by using MTT assay. The transcription level of genes Sox-9, Collagen-II, COMP, MMP-13 and oligomeric matrix protein was monitored by real-time PCR assay. The samples were also stained by Toluidine blue method to monitor the synthesis of proteoglycan. Results: Data demonstrated an increased survival rate in cells coated seeded on scaffolds, especially (PNIPAAm-PCL-PEG-PCL-PNIPAAm)/Gelatin as compared to control cells on the plastic surface. (PNIPAAm-PCL-PEG-PCL-PNIPAAm)/Gelatin had potential to increase the expression of genes Sox-6, Collagen-II, COMP and after 10 days in vitro. Conclusion: Thermosensitive PCEC/Gel and (PNIPAAm-PCEC-PNIPAAm)/Gel hydrogel scaffolds that fabricated by TIPS method possesses useful hydrophilic properties for growth and cell embedding and secretion of extracellular matrix. It can serve as an ideal strategy to promote the formation of cartilage tissue.
A novel method for the preparation of gelatin scaffolds was designed by varying the crosslinking temperature. Four pore size ranges of genipin-crosslinked gelatin scaffolds were made by varying the ...crosslinking temperature from 10 to 25°C, with the pore sizes ranging from 50 to 500μm. The pore size of the scaffold increases as the crosslinking temperature increases. Articular chondrocytes of Wistar rats were in vitro cultured in these scaffolds. DNA assay, glycosaminoglycan (GAG) assay, hematoxylin–eosin staining, Safranin-O staining and reverse transcription-polymerase chain reaction were performed to analyze the effect of the pore size on cell growth and the secretion of extracellular matrix (ECM). As the pores become larger, the rate of cell growth and the amount of GAG secretion increase, and the expressions of all four gene markers for aggrecan, collagen type I, collagen type II and collagen type X increase. The cells in the smaller pores often show a dedifferentiated form. The phenotype of the cells is maintained better in larger pores. Chondrocytes prefer the group of scaffolds with pore size between 250 and 500μm for better proliferation and ECM production. The size of the space for cell growth is a key factor for cell metabolism.
The challenges in achieving optimal outcomes for wound healing have persisted for decades, prompting ongoing exploration of interventions and management strategies. This study focuses on assessing ...the potential benefits of implementing a nano-gelatin scaffold for wound healing. Using a rat skin defect model, full-thickness incisional wounds were created on each side of the thoracic-lumbar regions after anesthesia. The wounds were left un-sutured, with one side covered by a gelatin nano-fibrous membrane and the other left uncovered. Wound size changes were measured on days 1, 4, 7, and 14, and on day 14, rats were sacrificed for tissue sample excision, examined with hematoxylin and eosin, and Masson’s trichrome stain. Statistical comparisons were performed. The gelatin nanofibers exhibited a smooth surface with a fiber diameter of 260 ± 40 nm and porous structures with proper interconnectivity. Throughout the 14-day experimental period, significant differences in the percentage of wound closure were observed between the groups. Histological scores were higher in the experiment group, indicating less inflammation but dense and well-aligned collagen fiber formation. A preliminary clinical trial on diabetic ulcers also demonstrated promising results. This study highlights the potential of the nano-collagen fibrous membrane to reduce inflammatory infiltration and enhance fibroblast differentiation into myofibroblasts during the early stages of cutaneous wound healing. The nano-fibrous collagen membrane emerges as a promising candidate for promoting wound healing, with considerable potential for future therapeutic applications.
Myocardial ischemia-reperfusion (MI/R) occurs due to temporary or permanent interruptions in the coronary and circulatory system, indirectly affecting kidney function through reduced cardiac output ...for metabolic needs. In this study, the aim was to explore the indirect effects of using human amniotic membrane mesenchymal stem cells (hAMSCs) with the PGS-co-PCL/PGC/PPy/Gelatin scaffold in male rats with renal failure induced by miocardial ischemia-reperfusion.
MI/R injury was induced in 48 male Wistar rats through left anterior descending artery ligation, divided into four groups (n=12); control group, cell group, scaffold group, and celss+scaffold group. Evaluations were conducted at two and thirty days post MI/R injury, encompassing echocardiography, biochemical, inflammatory markers analysis, and histological assessment.
Echocardiographic findings exhibited notable enhancement in ejection fraction, fractional shortening, and stroke volume of treated groups compared to controls after 30 days (P< 0.05). Serum creatinine (P< 0.001) and urea (P< 0.05) levels significantly decreased in the scaffold+cells group) compared to the control group. The treated cells+ scaffold group displayed improved kidney structure, evidenced by larger glomeruli and reduced Bowman's space compared to the control group (P< 0.01). Immunohistochemical analysis indicated reduced TNF-α protein in the scaffold+ cells group (P< 0.05) in contrast to the control group (P< 0.05). Inflammatory factors IL-6, TNF-α, and AKT gene expression in renal tissues were improved in scaffold+ cells-treated animals.
Our research proposes the combination of hAMSCs and the PGS-co-PCL/PGC/PPy/Gelatin scaffold in MI/R injured rats appears to enhance renal function and reduce kidney inflammation by improving cardiac output.
•Examine the indirect effects of employing hAMSCs with the PGS-co-PCL/PGC/PPy/Gelatin scaffold in male rats with renal failure caused by cardiac ischemia-reperfusion.•The kidney tissues were examined histologically to determine the renal structure under MI/R injury.
•Resveratrol rescues the OGD-mediated decrease in cells survival via the AMPK.•Resveratrol enhances the neuroprotective genes in OGD-exposed cells on scaffold.•Resveratrol increases mitochondrial ...functions in OGD-exposed cells on scaffold.
Ischemic stroke arising from the sudden blockage of arteries in the brain, is a common and serious brain damaging problem worldwide, often leading to disability or death. The oxygen glucose deprivation (OGD) model was created to improve understanding of hypoxia- and hypoglycemia-induced neuronal cell injury, and provide an in vitro surrogate to assess novel treatments for cerebral hypoxia-ischemia. AMP-activated protein kinase (AMPK) is a critical neuroprotective regulator of energy homeostasis, metabolism and cell survival. However, the neuroprotective mechanisms by which AMPK achieves these beneficial effects in human SH-SY5Y neural cells exposed to OGD are still not well understood. Resveratrol is a potent activator of AMPK suggesting it may have therapeutic potential as a neuroprotective agent. Therefore, we hypothesized the AMPK activator resveratrol protects against OGD-mediated impairment of human SH-SY5Y neuronal cells. The novelty of the experiment using a 3D gelatin scaffold cell culture assay, we have tested the potential of 3D systems to mimic the endogenous neuronal environment and have applied these systems to study the effect of OGD on neuronal cells with/without resveratrol. Here we show resveratrol reverses, via AMPK-dependent downregulation of caspase 3 and 9 activity, the OGD-mediated decreases in SH-SY5Y cell viability on a 3D gelatin scaffold. In addition, treatment with OGD decreases mRNA levels of AMPK and the neuroprotective genes (Bcl-2 and CREB); however, co-treatment with resveratrol significantly normalizes these effects. Importantly, resveratrol improves the expression of AMPK and p-AMPK in OGD-exposed SH-SY5Y cells. Resveratrol also significantly rescues SH-SY5Y cells from OGD-mediated mitochondrial deficiency (lower D-loop level, mitochondrial mass, maximal respiratory function, COX activity, and mitochondrial membrane potential). Resveratrol also rescues the transcript expression levels of PGC1α and mitochondrial genes (NRF-1 and Tfam) in OGD-treated SH-SY5Y cells. These findings extend our mechanistic understanding of the central role of AMPK in OGD-related neuronal impairment, and may serve as basis for implementing new therapeutic strategies in the treatment of ischemic stroke.
PDF
