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1.
Stem cell-based tissue engineering holds much hope for the development of multifunctional tissues to replace diseased organs. The attachment and survival of stem cells on a three-dimensional (3D) scaffold must be enhanced for faster progression of stem cell based tissue engineering. This study evaluate the stability of mesenchymal stem cells (MSCs) in 3D porous scaffolds composed of a collagen and chitosan blend impregnated with epidermal growth factor incorporated chitosan nanoparticles (EGF-CNP). The EGF-CNP scaffolds were characterized by transmission electron microscopy, which revealed that the nanoparticles were round in shape and 20 ∼ 50 nm in size. The scaffolds were prepared by freeze drying. A Fourier-transform infrared spectrum study revealed that the linkage between collagen and chitosan was through an ionic interaction. Thermal analysis and degradation studies showed that the scaffold could be used in tissue engineering application. MSCs proliferated well in the EGF-CNP impregnated scaffold. A scanning electron microscope study showed anchored and elongated MSCs on the EGF-CNP impregnated scaffold. A 3D biodegradable collagen chitosan scaffold impregnated with EGF-CNP is a promising transportable candidate for MSC-based tissue engineering, and this scaffold could be used as an in vitro model for subsequent clinical applications.  相似文献   

2.
Cyclin D1 overexpression is a common feature of many human malignancies. Genomic deletion analysis has demonstrated a key role for cyclin D1 in cellular proliferation, angiogenesis and cellular migration. To investigate the mechanisms contributing to cyclin D1 functions, we purified cyclin D1a-associated complexes by affinity chromatography and identified the PACSIN 2 (protein kinase C and casein kinase substrate in neurons 2) protein by mass spectrometry. The PACSIN 2, but not the related PACSIN 1 and 3, directly bound wild-type cyclin D1 (cyclin D1a) at the carboxyl terminus and failed to bind cyclin D1b, the alternative splicing variant of cyclin D1. PACSIN 2 knockdown induced cellular migration and reduced cell spreading in LNCaP cells expressing cyclin D1a. In cyclin D1−/− mouse embryonic fibroblasts (MEFs), cyclin D1a, but not cyclin D1b, reduced the cell spreading to a polarized morphology. siPACSIN 2 had no effect on cellular migration of cyclin D1−/− MEFs. Cyclin D1a restored the migratory ability of cyclin D1−/− MEFs, which was further enhanced by knocking down PACSIN 2 with siRNA. The cyclin D1-associated protein, PACSIN 2, regulates cell spreading and migration, which are dependent on cyclin D1 expression.Key words: PACSIN 2, cyclin D1, polymorphism, cellular migration, cell spreading, cancer  相似文献   

3.
Culturing cells in 3D on appropriate scaffolds is thought to better mimic the in vivo microenvironment and increase cell-cell interactions. The resulting 3D cellular construct can often be more relevant to studying the molecular events and cell-cell interactions than similar experiments studied in 2D. To create effective 3D cultures with high cell viability throughout the scaffold the culture conditions such as oxygen and pH need to be carefully controlled as gradients in analyte concentration can exist throughout the 3D construct. Here we describe the methods of preparing biocompatible pH responsive sol-gel nanosensors and their incorporation into poly(lactic-co-glycolic acid) (PLGA) electrospun scaffolds along with their subsequent preparation for the culture of mammalian cells. The pH responsive scaffolds can be used as tools to determine microenvironmental pH within a 3D cellular construct. Furthermore, we detail the delivery of pH responsive nanosensors to the intracellular environment of mammalian cells whose growth was supported by electrospun PLGA scaffolds. The cytoplasmic location of the pH responsive nanosensors can be utilized to monitor intracellular pH (pHi) during ongoing experimentation.  相似文献   

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Expansion of seeded human Wharton's jelly mesenchymal stem cells (hWJ-MSCs) on 2D culture plates and 3D nano-hydroxyapatite/chitosan/gelatin scaffolds, from morphology and osteoactivity points of view, were investigated. Cell attachment and spreading, temporal expression profiles of selected osteogenic gene and protein markers, intracellular alkaline phosphatase enzyme activity (ALP activity), and matrix mineralization were assayed over the course of the experiments. Morphological results demonstrated hWJ-MSCs had greater affinity to adhere onto the 3D scaffold surface, as the number and thickness of the filopodia were higher in the 3D compared with 2D culture system. Functionally, the intracellular ALP activity and extracellular mineralization in 3D scaffolds were significantly greater, in parallel with elevation of osteogenic markers at the mRNA and protein levels at all-time point. It is concluded that 3D scaffolds, more so than 2D culture plate, promote morphology and osteogenic behavior of WJ-MSCs in vitro, a promising system for MSCs expansion without compromising their stemness before clinical transplantation.  相似文献   

7.
Osteogenic differentiation of osteoprogenitor cells in three-dimensional (3D) in vitro culture remains poorly understood. Using quantitative real-time RT-PCR techniques, we examined mRNA expression of alkaline phosphatase, osteocalcin, and vascular endothelial growth factor (VEGF) in murine preosteoblastic MC3T3-E1 cells cultured for 48 h and 14 days on conventional two-dimensional (2D) poly(L-lactide-co-glycolide) (PLGA) films and 3D PLGA scaffolds. Differences in VEGF secretion and function between 2D and 3D culture systems were examined using Western blots and an in vitro Matrigel-based angiogenesis assay. Expression of both alkaline phosphatase and osteocalcin in cells cultured on 3D scaffolds was significantly downregulated relative to 2D controls in 48 h and 14 day cultures. In contrast, elevated levels of VEGF expression in 3D culture were noted at every time point in short- and long-term culture. VEGF protein secretion in 3D cultures was triple the amount of secretion observed in 2D controls. Conditioned medium from 3D cultures induced an enhanced level of angiogenic activity, as evidenced by increases in branch points observed in in vitro angiogenesis assays. These results collectively indicate that MC3T3-E1 cells commit to osteogenic differentiation at a slower rate when cultured on 3D PLGA scaffolds and that VEGF is preferentially expressed by these cells when they are cultured in three dimensions. gene expression; osteogenesis; angiogenesis  相似文献   

8.
The in vitro generation of a three‐dimensional (3‐D) myocardial tissue‐like construct employing cells, biomaterials, and biomolecules is a promising strategy in cardiac tissue regeneration, drug testing, and tissue engineering applications. Despite significant progress in this field, current cardiac tissue models are not yet able to stably maintain functional characteristics of cardiomyocytes for long‐term culture and therapeutic purposes. The objective of this study was to fabricate bioactive 3‐D chitosan nanofiber scaffolds using an electrospinning technique and exploring its potential for long‐term cardiac function in the 3‐D co‐culture model. Chitosan is a natural polysaccharide biomaterial that is biocompatible, biodegradable, non‐toxic, and cost effective. Electrospun chitosan was utilized to provide structural scaffolding characterized by scale and architectural resemblance to the extracellular matrix (ECM) in vivo. The chitosan fibers were coated with fibronectin via adsorption in order to enhance cellular adhesion to the fibers and migration into the interfibrous milieu. Ventricular cardiomyocytes were harvested from neonatal rats and studied in various culture conditions (i.e., mono‐ and co‐cultures) for their viability and function. Cellular morphology and functionality were examined using immunofluorescent staining for alpha‐sarcomeric actin (SM‐actin) and gap junction protein, Connexin‐43 (Cx43). Scanning electron microscopy (SEM) and light microscopy were used to investigate cellular morphology, spatial organization, and contractions. Calcium indicator was used to monitor calcium ion flux of beating cardiomyocytes. The results demonstrate that the chitosan nanofibers retained their cylindrical morphology in long‐term cell cultures and exhibited good cellular attachment and spreading in the presence of adhesion molecule, fibronectin. Cardiomyocyte mono‐cultures resulted in loss of cardiomyocyte polarity and islands of non‐coherent contractions. However, the cardiomyocyte‐fibroblast co‐cultures resulted in polarized cardiomyocyte morphology and retained their morphology and function for long‐term culture. The Cx43 expression in the fibroblast co‐culture was higher than the cardiomyocytes mono‐culture and endothelial cells co‐culture. In addition, fibroblast co‐cultures demonstrated synchronized contractions involving large tissue‐like cellular networks. To our knowledge, this is the first attempt to test chitosan nanofiber scaffolds as a 3‐D cardiac co‐culture model. Our results demonstrate that chitosan nanofibers can serve as a potential scaffold that can retain cardiac structure and function. These studies will provide useful information to develop a strategy that allows us to generate engineered 3‐D cardiac tissue constructs using biocompatible and biodegradable chitosan nanofiber scaffolds for many tissue engineering applications. Biotechnol. Bioeng. 2013; 110: 637–647. © 2012 Wiley Periodicals, Inc.  相似文献   

9.
Cell and extracellular matrix (ECM) interaction plays an important role in development and normal cellular function. Cell adhesion and cell spreading on ECM are two basic cellular behaviors related to cell-ECM interaction. Here we show that palladin, a novel actin cytoskeleton-associated protein, is actively involved in the regulation of cell-ECM interaction. It was found that palladin-deficient mouse embryonic fibroblasts (MEFs) display decreased cell adhesion and compromised cell spreading on various ECMs. Disorganized actin cytoskeleton architecture characterized by faint stress fibers, less lamellipodia and focal adhesions can account for the weakened cell-ECM interaction in palladin(-/-) MEFs. Furthermore, decreased polymerized filament actin and increased globular actin can be observed in palladin(-/-) MEFs, strongly suggesting that palladin is essential for the formation or stabilization of polymerized filament actin. Elevated phospho-cofilin level and proper responses in cofilin phosphorylation to either Rho signal agonist or antagonist in palladin(-/-) MEFs indicate that disrupted stress fibers in palladin(-/-) MEFs is not associated with cofilin phosphorylation. More interestingly, the protein level of ECM receptor beta1-integrin is dramatically decreased in MEFs lacking palladin. Down-regulation of beta1-integrin protein can be restored by proteasome inhibitor MG-132 treatment. All these data implicate that palladin is essential for cell-ECM interaction through maintaining normal actin cytoskeleton architecture and stabilizing beta1-integrin protein.  相似文献   

10.
In the present work, different biopolymer blend scaffolds based on the silk protein fibroin from Bombyx mori (BM) were prepared via freeze‐drying method. The chemical, structural, and mechanical properties of the three dimensional (3D) porous silk fibroin (SF) composite scaffolds of gelatin, collagen, and chitosan as well as SF from Antheraea pernyi (AP) and the recombinant spider silk protein spidroin (SSP1) have been systematically investigated, followed by cell culture experiments with epithelial prostate cancer cells (LNCaP) up to 14 days. Compared to the pure SF scaffold of BM, the blend scaffolds differ in porous morphology, elasticity, swelling behavior, and biochemical composition. The new composite scaffold with SSP1 showed an increased swelling degree and soft tissue like elastic properties. Whereas, in vitro cultivation of LNCaP cells demonstrated an increased growth behavior and spheroid formation within chitosan blended scaffolds based on its remarkable porosity, which supports nutrient supply matrix. Results of this study suggest that silk fibroin matrices are sufficient and certain SF composite scaffolds even improve 3D cell cultivation for prostate cancer research compared to matrices based on pure biomaterials or synthetic polymers.  相似文献   

11.
The roles of JSAP1 and JIP1 in cell adhesion and spreading were examined using mouse embryonic fibroblasts (MEFs) deficient in JIP1 (JIP1-KO), JSAP1 (JSAP1-KO), and in both JIP1 and JSAP1 (double-KO), and by using their wild type. After being plated on fibronectin-coated culture plates, wild type MEFs rapidly adhered and differentiated to typical longitudinal fibroblasts in 4 h. JSAP1-KO MEFs showed a similar sequence of adhesion and cell spreading, but their adhesion was weak, and cell spreading sequence proceeded in a delayed manner compared with the wild type. In spreading JSAP1-KO MEFs, adhesion-triggered actin cytoskeleton reorganization and FAK activation proceeded at a slower pace than in wild type MEFs. The cellular properties of double-KO MEFs and JIP1-KO MEFs were similar to those of JSAP1-KO MEFs and wild type MEFs, respectively. These results suggest that JSAP1 plays a role in adhesion and cell spreading by regulating the rapid reorganization of the actin cytoskeleton.  相似文献   

12.
In search for novel biomimetic scaffolds for application in vascular tissue engineering, we evaluated a series of fibrous scaffolds prepared by coelectrospinning tertiary blends of poly(lactide-co-glycolide) (PLGA), gelatin, and elastin (PGE). By systematically varying the ratios of PLGA and gelatin, we could fine-tune fiber size and swelling upon hydration as well as the mechanical properties of the scaffolds. Of all PGE blends tested, PGE321 (PLGA, gelatin, elastin v/v/v ratios of 3:2:1) produced the smallest fiber size (317 ± 46 nm, 446 ± 69 nm once hydrated) and exhibited the highest Young's modulus (770 ± 131 kPa) and tensile strength (130 ± 7 kPa). All PGE scaffolds supported the attachment and metabolization of human endothelial cells (ECs) and bovine aortic smooth muscle cells (SMCs) with some variances in EC morphology and cytoskeletal spreading observed at 48 h postseeding, whereas no morphologic differences were observed at confluence (day 8). The rate of metabolization of ECs, but not of SMCs, was lower than that on tissue culture plastic and depended on the specific PGE composition. Importantly, PGE scaffolds were capable of guiding the organotypic distribution of ECs and SMCs on and within the scaffolds, respectively. Moreover, the EC monolayer generated on the PGE scaffold surface was nonthrombogenic and functional, as assessed by the basal and cytokine-inducible levels of mRNA expression and amidolytic activity of tissue factor, a key player in the extrinsic clotting cascade. Taken together, our data indicate the potential application of PGE scaffolds in vascular tissue engineering.  相似文献   

13.
Three-dimensional fibrous PLGA/HAp composite scaffold for BMP-2 delivery   总被引:1,自引:0,他引:1  
A protein loaded three-dimensional scaffold can be used for protein delivery and bone tissue regeneration. The main objective of this project was to develop recombinant human bone morphogenetic protein-2 (rhBMP-2) loaded poly(D,L-lactide-co-glycolide)/hydroxylapatite (PLGA/HAp) composite fibrous scaffolds through a promising fabrication technique, electrospinning. In vitro release of BMP-2 from these scaffolds, and the attachment ability and viability of marrow derived messenchymal stem cells (MSCs) in the presence of the scaffolds were investigated. The PLGA/HAp composite scaffolds developed in this study exhibit good morphology and it was observed that HAp nanoparticles were homogeneously dispersed inside PLGA matrix within the scaffold. The composite scaffolds allowed sustained (2-8 weeks) release of BMP-2 whose release rate was accelerated with increasing HAp content. It was also shown that BMP-2 protein successfully maintained its integrity and natural conformations after undergoing the process of electrospinning. Cell culture experiments showed that the encapsulation of HAp could enhance cell attachment to scaffolds and lower cytotoxicity.  相似文献   

14.
This study presents the application of the porous poly(D,L-lactic-co-glycolic acid) (PLGA) sponges fabricated from an organic solvent free supercritical gas foaming technique. Two formulations of PLGA sponges with different co-polymer compositions (85:15 and 50:50) were fabricated as novel scaffolds to guide human hepatoma cell line, Hep3B cell growth in vitro. The PLGA sponges showed desirable biodegradability and exhibited uniform pore size distribution with moderate interconnectivity. It was observed in this study that cells cultured on PLGA sponges showed lower proliferation rate as compared to the control during 14 days of culture as measured by using total DNA and methylthiazol tetrazolium (MTT) assays. However, the cells cultured on the sponges tended to aggregate to form cell islets which were able to express better hepatic functions. The enzyme-linked immunosorbent assay (ELISA) results showed that the cell-sponge constructs secreted 1.5-3.0 times more albumin than the control when normalized to cellular content. In a similar fashion, its detoxification ability was also predominantly higher than that of the control as indicated by the ethoxyresorufin-O-deethylase (EROD) results. By comparing the cells growing on the two formulations of PLGA sponges, it was found that the PLGA 85:15 sponge exhibited better conductive and desirable environment for hep3B cells as justified by better cell infiltration, higher proliferation and hepatic function than the PLGA 50:50 sponge.  相似文献   

15.
In this study, natural biodegradable polysaccharide, chitosan, and synthetic biodegradable polymer, poly(?-caprolactone) (PCL) were used to prepare 3D, hybrid polymeric tissue scaffolds (PCL/chitosan blend and PCL/chitosan/PCL layer by layer scaffolds) by using the electrospinning technique. The hybrid scaffolds were developed through HA addition to accelerate osteoblast cell growth. Characteristic examinations of the scaffolds were performed by micrometer, SEM, contact angle measurement system, ATR-FTIR, tensile machine and swelling experiments. The thickness of all electrospun scaffolds was determined in the range of 0.010 ± 0.001-0.012 ± 0.002 mm. In order to optimize electrospinning processes, suitable bead-free and uniform scaffolds were selected by using SEM images. Blending of PCL with chitosan resulted in better hydrophilicity for the PCL/chitosan scaffolds. The characteristic peaks of PCL and chitosan in the blend and layer by layer nanofibers were observed. The PCL/chitosan/PCL layer by layer structure had higher elastic modulus and tensile strength values than both individual PCL and chitosan structures. The layer by layer scaffolds exhibited the PBS absorption values of 184.2; 197.2% which were higher than those of PCL scaffolds but lower than those of PCL/chitosan blend scaffolds. SaOs-2 osteosarcoma cell culture studies showed that the highest ALP activities belonged to novel PCL/chitosan/PCL layer by layer scaffolds meaning better cell differentiation on the surfaces.  相似文献   

16.
Embryonic stem cells (ESCs) are an important source of cardiomyocytes for regenerating injured myocardium. The successful use of ESC-derived cardiomyocytes in cardiac tissue engineering requires an understanding of the important scaffold properties and culture conditions to promote cell attachment, differentiation, organization, and contractile function. The goal of this work was to investigate how scaffold architecture and coculture with fibroblasts influences the differentiated phenotype of murine ESC-derived cardiomyocytes (mESCDCs). Electrospinning was used to process an elastomeric biodegradable polyurethane (PU) into aligned or unaligned fibrous scaffolds. Bioreactor produced mESCDCs were seeded onto the PU scaffolds either on their own or after pre-seeding the scaffolds with mouse embryonic fibroblasts (MEFs). Viable mESCDCs attached to the PU scaffolds and were functionally contractile in all conditions tested. Importantly, the aligned scaffolds led to the anisotropic organization of rod-shaped cells, improved sarcomere organization, and increased mESCDC aspect ratio (length-to-diameter ratio) when compared to cells on the unaligned scaffolds. In addition, pre-seeding the scaffolds with MEFs improved mESCDC sarcomere formation compared to mESCDCs cultured alone. These results suggest that both fiber alignment and pre-treatment of scaffolds with fibroblasts improve the differentiation of mESCDCs and are important parameters for developing engineered myocardial tissue constructs using ESC-derived cardiac cells.  相似文献   

17.
A low-density, porous chitosan/poly-(dl-lactide-co-glycolide) (PLGA) microparticle composite scaffold was produced by thermally induced phase separation followed by lyophilization, to provide a bicontinuous microstructure potentially suitable for tissue engineering and locally controlled drug release. PLGA particles were mixed into the chitosan solution and subsequent phase separation during chitosan solidification forced PLGA particles into chitosan phase (Plateau borders). The distributions of volume, surface area, and elongation of 15,422 inclusions of agglomerated PLGA particles were calculated and approximated with log-normal distribution functions from nanotomography reconstructions. Cluster analysis revealed a homogenous inclusion distribution throughout the scaffold. The spatial location and orientation of individual inclusions within the Plateau borders of the scaffold were determined and from these the nearest-neighbor inter-inclusion distance distribution calculated, showing a mean of 2.5 microm. The depth of the inclusions in Plateau borders peaks at 700 or 125 nm, respectively, indicating a step-wise drug release from inclusions successively exposed during scaffold decomposition. Particle diameter ranged from 400 nm to 3 microm and inclusion Feret lengths ranged from 800 nm to 12 microm. These findings on composite morphology and distribution of inclusions are fundamental for predicting scaffold deterioration and particle-mediated drug release during ex vivo and in vivo cell cultivation.  相似文献   

18.
Cyclin D1 is overexpressed in human tumors, correlating with cellular metastasis, and is induced by activating Rho GTPases. Herein, cyclin D1-deficient mouse embryo fibroblasts (MEFs) exhibited increased adhesion and decreased motility compared with wild-type MEFs. Retroviral transduction of cyclin D1 reversed these phenotypes. Mutational analysis of cyclin D1 demonstrated that its effects on cellular adhesion and migration were independent of the pRb and p160 coactivator binding domains. Genomewide expression arrays identified a subset of genes regulated by cyclin D1, including Rho-activated kinase II (ROCKII) and thrombospondin 1 (TSP-1). cyclin D1(-/-) cells showed increased Rho GTP and ROCKII activity and signaling, with increased phosphorylation of LIM kinase, cofilin (Ser3), and myosin light chain 2 (Thr18/Ser19). Cyclin D1 repressed ROCKII and TSP-1 expression, and the migratory defect of cyclin D1(-/-) cells was reversed by ROCK inhibition or TSP-1 immunoneutralizing antibodies. cyclin E knockin to the cyclin D1(-/-) MEFs rescued the DNA synthesis defect of cyclin D1(-/-) MEFs but did not rescue either the migration defect or the abundance of ROCKII. Cyclin D1 promotes cellular motility through inhibiting ROCK signaling and repressing the metastasis suppressor TSP-1.  相似文献   

19.
Electrospun nanofibrous scaffolds varying different materials are fabricated for tissue engineering. PLGA, silk fibroin, and collagen-derived scaffolds have been proved on good biocompatibility with neurons. However, no systematic studies have been performed to examine the PLGA-silk fibroin-collagen (PLGA-SF-COL) biocomposite fiber matrices for nerve tissue engineering. In this study, different weight ratio PLGA-SF-COL (50:25:25, 30:35:35) scaffolds were produced via electrospinning. The physical and mechanical properties were tested. The average fiber diameter ranged from 280 + 26 to 168 + 21 nm with high porosity and hydrophilicity; the tensile strength was 1.76 ± 0.32 and 1.25 ± 0.20 Mpa, respectively. The results demonstrated that electrospinning polymer blending is a simple and effective approach for fabricating novel biocomposite nanofibrous scaffolds. The properties of the scaffolds can be strongly influenced by the concentration of collagen and silk fibroin in the biocomposite. To assay the cytocompatibility, Schwann cells were seeded on the scaffolds; cell attachment, growth morphology, and proliferation were studied. SEM and MTT results confirmed that PLGA-SF-COL scaffolds particularly the one that contains 50% PLGA, 25% silk fibroin, and 25% collagen is more suitable for nerve tissue engineering compared to PLGA nanofibrous scaffolds.  相似文献   

20.
The production, characterization and anti-biofouling activity of 3D porous scaffolds combining different blends of chitosan and oxazoline-based antimicrobial oligomers is reported. The incorporation of ammonium quaternized oligo(2-oxazoline)s into the composition of the scaffold enhances the stability of the chitosan scaffold under physiological conditions as well as its ability to repel protein adsorption. The blended scaffolds showed mean pore sizes in the range of 18–32?μm, a good pore interconnectivity and high porosity, as well as a large surface area, ultimate key features for anti-biofouling applications. Bovine serum albumin (BSA) adhesion profiles showed that the composition of the scaffolds plays a critical role in the chitosan–oligooxazoline system. Oligobisoxazoline-enriched scaffolds (20%?w/w, CB8020) decreased protein adsorption (BSA) by up to 70%. Moreover, 1?mg of CB8020 was able to kill 99.9% of Escherichia coli cells upon contact, demonstrating its potential as promising material for production of tailored non-fouling 3D structures to be used in the construction of novel devices with applications in the biomedical field and water treatment processes.  相似文献   

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