Col Scaffolds Research Articles

Collagen-silica bio-composite enriched with Cynodon dactylon extract for tissue repair and regeneration

Development of biomaterials for tissue engineering applications is of great interest to meet the demand of different clinical requirements. The wound heal dressing biomaterials should necessarily contain well-defined therapeutic components and desirable physical, chemical and biological properties to support optimal delivery of therapeutics at the site of the wound. In this study, we developed collagen-silica wound heal scaffold incorporated with the extract of Cynodon dactylon, characterized and evaluated for its wound heal potential in vitro and in vivo against collagen (Col) and Collagen-silica (CS) scaffolds that served as controls. The prepared Collagen-Silica-Cynodon extract (CSCE) scaffold exhibits porous morphology with preferable biophysical, chemical, mechanical and mass transfer properties besides its controlled biodegradation at the wound site. Stability of CSCE was found to be better than that of native collagen due to intermolecular interactions between collagen and constituents of C. dactylon as confirmed by FTIR analysis. Notably, in vitro biocompatibility assay using DAPI and Rhodamine 123 staining demonstrated that the proliferation of NIH3T3 fibroblast cells was better for CSCE when compared to the Col and CS scaffolds. In vivo wound healing experiments with full-thickness excision wounds in wistar rat model demonstrated that the wounds treated with CSCE showed accelerated healing with enhanced collagen deposition when compared to wounds treated with Col and CS scaffolds, and these studies substantiated the efficacy of CSCE scaffold for treating wounds.

Shape-memory collagen scaffold for enhanced cartilage regeneration: native collagen versus denatured collagen

Nowadays, it is still questionable whether denatured collagen (DCol) can replace the native collagen (Col) as a bioactive protein in cartilage engineering. We sought to study the advantages of Col with a triple-helical structure in the collagen-based composite materials for cartilage engineering. We presented new three-dimensional (3D) Col and DCol scaffolds with shape memory properties. The effects of Col and DCol scaffolds on rabbit chondrocytes' proliferation, adhesion, differentiation and interaction with matrix were investigated. Tissue compatibility was performed in a subcutaneous Sprague Dawley (SD) rat model. The repair ability of different scaffolds with chondrocytes for full-thickness articular cartilage defects in knee joints of New Zealand white rabbits were investigated. The results indicated that the Col scaffolds (with concentration 1.6wt% and 0.8wt%, respectively) promoted the proliferation, adhesion and redifferentiation of chondrocytes, as well as chondrocyte-matrix interaction, to a greater degree than the DCol scaffolds. In the animal experiment, the Col scaffolds filled in the defect hole significantly maintained chondrocytes function, promoted cartilage and subchondral bone regeneration, compared with the DCol scaffolds, and the scaffolds loaded with chondrocytes were better than the cell-free scaffolds, especially in the case of the Col scaffolds (1.6 wt%). Taken together, these insights suggest that the better proliferation, adhesion and redifferentiation of chondrocytes in Col scaffolds with the triple-helical structure may contribute to the greater cartilage repair ability. Col scaffolds may be more appropriate for repairing cartilage defects than DCol scaffolds, and DCol cannot as an alternative when using collagen-based materials for cartilage engineering applications.

An improvement of silk-based scaffold properties using collagen type I for skin tissue engineering applications

Silk has been intensively studied for tissue engineering applications owning to its advantages of biodegradability, tunable mechanical properties, versatile processing, and biocompatibility. Silk, however, has few cell signaling domains, so silk alone might not be sufficient to use as the scaffolds for tissue engineering. Here, we demonstrated the improvement of silk scaffold properties by the incorporation of type I collagen [Col; 0, 3.61, 7.69, 14.89, and 50% (w/w)] into silk-based scaffolds. The morphology and properties, including biocompatibility, of the scaffolds were then investigated. Notably, moderate amounts of Col (7.69 and 14.89%) improved fibroblast attachment and supported proliferation on the scaffolds compared to those of silk alone. Both 7.69 and 14.89% Col scaffolds exhibited more organized and smaller pore sizes (144.09 ± 25.97 and 140.67 ± 38.28 μm in diameter, respectively) with thinner walls compared to higher silk content (0 and 3.61% Col) scaffolds. The 7.69 and 14.89% Col also improved the scaffold stability over 21 days, whereas silk alone scaffolds dramatically lost their weight by day 21. The incorporation of collagen also increased water adsorption ability of the scaffolds. Therefore, this study demonstrated the effects of type I collagen toward improving the properties of silk-based scaffolds.

Collagenous scaffolds supplemented with hyaluronic acid and chondroitin sulfate used for wound fibroblast and embryonic nerve cell culture.

Tissue engineering is a strategy aimed at improving the regeneration of injured tissues. The aim of the present study was to determine whether a tri-copolymer composed of crosslinked collagen, chondroitin sulfate and hyaluronic acid (Col + CS + HA) provides a better environment for fibroblast and embryonic nerve cell culture than a collagenous scaffold (Col). The porosity of each of the matrices was characterized with a scanning electron microscope. Fibroblasts were isolated from rat wound granulation tissue (polypropylene net implanted subcutaneously). Embryonic nerve cells were obtained from the brains of rat embryos. The cells were applied to scaffolds and then stained with bisbenzimide to calculate cell entrapment within the material. The metabolic activity of the cells cultured within the scaffolds was tested using the 3-(4,5-dimethythiazol2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. The Col scaffolds had a homogenously porous structure with a pore diameter of 50 μm for 70% of pores. The pore diameter in the tri-copolymer (Col + HA + CS) ranged from 24 to 160 μm (95% of total pore volume). Four times more cells (fibroblasts and embryonic nerve cells) were trapped within the superficial part of the collagenous scaffold than that of the tri-copolymer. On the third day of culture the metabolic activity of the fibroblasts within the 2 tested scaffolds was significantly higher than in the control conditions (cell culture on a laminin-coated surface). Also, the embryonic nerve cells demonstrated increased metabolic activity in Col + CS + HA scaffolds than the Col scaffolds. Both fibroblasts and embryonic nerve cells could be seeded within the 2 tested scaffolds. Both the scaffolds provide good conditions for fibroblast culture. However, the Col + CS + HA tri-copolymer is preferable for embryonic nerve cell engineering.

Human Cartilage Engineering in an In Vitro Repair Model Using Collagen Scaffolds and Mesenchymal Stromal Cells.

The purpose of this study was to investigate cartilage repair of in vitro lesion models using human bone marrow mesenchymal stromal cells (hBMSCs) with different collagen (Col) scaffolds.Lesions were made in human cartilage biopsies. Injured samples were pre-treated with interleukin 1β (IL1β) for 24 h; also, samples were not pre-treated. hBMSCs were seeded on different types of collagen scaffolds. The resulting constructs were placed into the lesions, and the biopsies were cultured for 2 months in chondrogenic medium.Using the modified ICRSII scale, neotissues from the different scaffolds showed ICRS II overall assessment scores ranging from 50% (fibrocartilage) to 100% (hyaline cartilage), except for the Col I +Col II +HS constructs (fibrocartilage/hyaline cartilage, 73%). Data showed that hBMSCs cultured only on Col I +Col II +HS scaffolds displayed a chondrocyte-like morphology and cartilage-like matrix close to native cartilage. Furthermore, IL1β pre-treated biopsies decreased capacity for repair by hBMSCs and decreased levels of chondrogenic phenotype of human cartilage lesions.

Micro/Nano Multilayered Scaffolds of PLGA and Collagen by Alternately Electrospinning for Bone Tissue Engineering.

The dual extrusion electrospinning technique was used to fabricate multilayered 3D scaffolds by stacking microfibrous meshes of poly(lactic acid-co-glycolic acid) (PLGA) in alternate fashion to micro/nano mixed fibrous meshes of PLGA and collagen. To fabricate the multilayered scaffold, 35 wt% solution of PLGA in THF-DMF binary solvent (3:1) and 5 wt% solution of collagen in hexafluoroisopropanol (HFIP) with and without hydroxyapatite nanorods (nHA) were used. The dual and individual electrospinning of PLGA and collagen were carried out at flow rates of 1.0 and 0.5 mL/h, respectively, at an applied voltage of 20 kV. The density of collagen fibers in multilayered scaffolds has controlled the adhesion, proliferation, and osteogenic differentiation of MC3T3-E1 cells. The homogeneous dispersion of glutamic acid-modified hydroxyapatite nanorods (nHA-GA) in collagen solution has improved the osteogenic properties of fabricated multilayered scaffolds. The fabricated multilayered scaffolds were characterized using FT-IR, X-ray photoelectron spectroscopy, and transmission electron microscopy (TEM). The scanning electron microscopy (FE-SEM) was used to evaluate the adhesion and spreads of MC3T3-E1 cells on multilayered scaffolds. The activity of MC3T3-E1 cells on the multilayered scaffolds was evaluated by applying MTT, alkaline phosphatase, Alizarin Red, von Kossa, and cytoskeleton F-actin assaying protocols. The micro/nano fibrous PLGA-Col-HA scaffolds were found to be highly bioactive in comparison to pristine microfibrous PLGA and micro/nano mixed fibrous PLGA and Col scaffolds.

Retracted] Restoration of Critical‐Sized Defects in the Rabbit Mandible Using Autologous Bone Marrow Stromal Cells Hybridized with Nano‐β‐tricalcium Phosphate/Collagen Scaffolds

Nano‐β‐tricalcium phosphate/collagen (n‐β‐TCP/Col) is considered with good osteoconductivity. However, the therapeutic effectiveness of n‐β‐TCP/Col scaffolds in combination with autologous bone marrow stromal cells (BMSCs) remains to be elucidated for the repair of critical‐sized bone defects. In this study, we found that n‐β‐TCP/Col scaffolds exhibited high biocompatibility in vitro. The introduction of BMSCs expanded in vitro to the scaffolds dramatically enhanced their efficiency to restore critical‐sized bone defects, especially during the initial stage after implantation. Collectively, these results suggest that autologous BMSCs in n‐β‐TCP/Col scaffolds have the potential to be applied in bone tissue engineering.

Mesenchymal Stem Cell Responses to Bone-Mimetic Electrospun Matrices Composed of Polycaprolactone, Collagen I and Nanoparticulate Hydroxyapatite

The performance of biomaterials designed for bone repair depends, in part, on the ability of the material to support the adhesion and survival of mesenchymal stem cells (MSCs). In this study, a nanofibrous bone-mimicking scaffold was electrospun from a mixture of polycaprolactone (PCL), collagen I, and hydroxyapatite (HA) nanoparticles with a dry weight ratio of 50/30/20 respectively (PCL/col/HA). The cytocompatibility of this tri-component scaffold was compared with three other scaffold formulations: 100% PCL (PCL), 100% collagen I (col), and a bi-component scaffold containing 80% PCL/20% HA (PCL/HA). Scanning electron microscopy, fluorescent live cell imaging, and MTS assays showed that MSCs adhered to the PCL, PCL/HA and PCL/col/HA scaffolds, however more rapid cell spreading and significantly greater cell proliferation was observed for MSCs on the tri-component bone-mimetic scaffolds. In contrast, the col scaffolds did not support cell spreading or survival, possibly due to the low tensile modulus of this material. PCL/col/HA scaffolds adsorbed a substantially greater quantity of the adhesive proteins, fibronectin and vitronectin, than PCL or PCL/HA following in vitro exposure to serum, or placement into rat tibiae, which may have contributed to the favorable cell responses to the tri-component substrates. In addition, cells seeded onto PCL/col/HA scaffolds showed markedly increased levels of phosphorylated FAK, a marker of integrin activation and a signaling molecule known to be important for directing cell survival and osteoblastic differentiation. Collectively these results suggest that electrospun bone-mimetic matrices serve as promising degradable substrates for bone regenerative applications.

Porcine bone marrow stromal cell differentiation on heparin-adsorbed poly(e-caprolactone)–tricalcium phosphate–collagen scaffolds

We evaluate the potential of heparin as a substrate component for the fabrication of bone tissue engineering constructs using poly(e-caprolactone)–tricalcium phosphate–collagen type I (PCL–TCP–Col) three-dimensional (3-D) scaffolds. First we explored the ability of porcine bone marrow precursor cells (MPCs) to differentiate down both the adipogenic and osteogenic pathways within 2-D culture systems, with positive results confirmed by Oil-Red-O and Alizarin Red staining, respectively. Secondly, we examined the influence of heparin on the interaction and behaviour of MPCs when seeded onto PCL–TCP–Col 3-D scaffolds, followed by their induction into the osteogenic lineage. Our 3-D findings suggest that cell metabolism and proliferation increased between days 1 and 14, with deposition of extracellular matrix also observed up to 28 days. However, no noticeable difference could be detected in the extent of osteogenesis for PCL–TCP–Col scaffolds groups with the addition of heparin compared to identical control scaffolds without the addition of heparin.