Acidic pH resistance of grafted chitosan on dental implant (original) (raw)
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Surface Entrapment of Fibronectin on Electrospun PLGA Scaffolds for Periodontal Tissue Engineering
BioResearch Open Access, 2014
Nowadays, the challenge in the tissue engineering field consists in the development of biomaterials designed to regenerate ad integrum damaged tissues. Despite the current use of bioresorbable polyesters such as poly(l-lactide) (PLA), poly(d,l-lactide-co-glycolide) (PLGA), and poly-e-caprolactone in soft tissue regeneration researches, their hydrophobic properties negatively influence the cell adhesion. Here, to overcome it, we have developed a fibronectin (FN)-functionalized electrospun PLGA scaffold for periodontal ligament regeneration. Functionalization of electrospun PLGA scaffolds was performed by alkaline hydrolysis (0.1 or 0.01 M NaOH). Then, hydrolyzed scaffolds were coated by simple deposition of an FN layer (10 lg/mL). FN coating was evidenced by X-ray photoelectron analysis. A decrease of contact angle and greater cell adhesion to hydrolyzed, FN-coated PLGA scaffolds were noticed. Suitable degradation behavior without pH variations was observed for all samples up to 28 days. All treated materials presented strong shrinkage, fiber orientation loss, and collapsed fibers. However, functionalization process using 0.01 M NaOH concentration resulted in unchanged scaffold porosity, preserved chemical composition, and similar mechanical properties compared with untreated scaffolds. The proposed simplified method to functionalize electrospun PLGA fibers is an efficient route to make polyester scaffolds more biocompatible and shows potential for tissue engineering.
Surface modification of electrospun PLGA scaffold with collagen for bioengineered skin substitutes
In skin tissue engineering, surface feature of the scaffolds plays an important role in cell adhesion and proliferation. In this study, non-woven fibrous substrate based on poly (lactic-co-glycolic acid) (PLGA) (75/25) were hy-drolyzed in various concentrations of NaOH (0.05 N, 0.1 N, 0.3 N) to increase carboxyl and hydroxyl groups on the fiber surfaces. These functional groups were activated by EDC/NHS to create chemical bonding with collagen. To improve bioactivity, the activated substrates were coated with a collagen solution (2 mg/ml) and cross-linking was carried out using the EDC/NHS in MES buffer. The effectiveness of the method was evaluated by contact angle measurements, porosimetry, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), tensile and degradation tests as well as in vitro cell attachment and cytotoxicity assays. Cell culture results of human dermal fibroblasts (HDF) and keratinocytes cell line (HaCat) revealed that the cells could attach to the scaffold. Further investigation with MTT assay showed that the cell proliferation of HaCat significantly increases with collagen coating. It seems that sufficient stability of collagen on the surface due to proper chemical bonding and cross-linking has increased the bioactivity of surface remarkably which can be promising for bioengineered skin applications.
… Research Part A, 2006
Engineering functional three-dimensional (3-D) tissue constructs for the replacement and/or repair of damaged native tissues using cells and scaffolds is one of the ultimate goals of tissue engineering. In this study, non-woven fibrous scaffolds were electrospun from the synthetic biodegradable polymer poly(lactic-co-glycolic acid) (PLGA) and natural proteins, gelatin (denatured collagen) and elastin. In the absence of cross-linking agent, the average PGE fiber diameter increased from 347 ± 103 nm to 999 ± 123 nm upon wetting as measured by scanning electron microscopy. Rat bone marrow stromal cells (rBMSC) were used paradigmatically to study the 3-D cell culture properties of PGE scaffolds. Consistent with the observed properties of the individual fibers, PGE scaffolds initially swelled in aqueous culture medium, however rBMSC seeded PGE scaffolds contracted to < 50% of original size. Time course histological analysis demonstrated uniform seeding of rBMSC into PGE scaffolds and complete cell penetration into the fibrous architecture over 4 weeks of in vitro culture.
Electrospun blends of natural and synthetic polymers as scaffolds for tissue engineering
2006
Abstract Engineering functional three-dimensional (3-D) tissue constructs for the replacement and/or repair of damaged native tissues using cells and scaffolds is one of the ultimate goals of tissue engineering. In this study, non-woven fibrous scaffolds were electrospun from the synthetic biodegradable polymer poly (lactic-co-glycolic acid)(PLGA) and natural proteins, gelatin (denatured collagen) and elastin.
Tissue Engineering and Regenerative Medicine, 2016
Most cells in the human body grow and live in a complex network of biomaterials usually known as the extracellular matrix, which is composed of various proteins and proteoglycans assembled into a highly ordered structure [1-3]. In regenerative medicine, when new tissue needs to be grown intra or extra corporally, there are fundamental aspects to be considered for the construction, development and functionality of living tissue: bioactive molecules together with a scaffold, used as a support for the cells, are needed to mimic the extracellular matrix and promote cell adhesion, proliferation, differentiation, and migration pathways [4,5]. Producing scaffolds for tissue engineering demands the development of new materials with bioactive molecules and an appropriated technique. Among the techniques to produce polymeric scaffolds, electrospinning is a simple and effective method to obtain nanofiber-based scaffolds resembling the functions of the extracellular matrix [6-10]. Regarding the materials, a number of natural and synthetic polymers have been used to produce electrospun scaffolds [11-15]. Poly (lactic acid) (PLA) is widely used for the generation of scaffolds for tissue engineering to allow precise control over their physicochemical and mechanical properties but exhibit limited cellular affinity. Natural biodegradable polymers, such as collagen, provide inherent binding sites for the promotion of cell adhesion and cellular growth. However, this natural material, obtained from animal or human tissues, is expensive and
"Abstract Repair or replacement of damaged tissues using tissue engineering technology is considered to be a fine solution for enhanced treatment of different diseases such as skin diseases. Although the nanofibers made of synthetic degradable polymers, such as polylactic acid (PLA), have been widely used in the medical field, they do not favour cellular adhesion and proliferation. To enhance cell adherence on scaffold and improve biocompatibility, the surface of PLA scaffold was modified by gelatin in our experiments. For electrospinning, PLA and gelatin were dissolved in hexafluoroisopropanol (HFIP) solvent at varying compositions (PLA:gelatin at 3:7 and 7:3). The properties of the blending nanofiber scaffold were investigated by Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). Modified PLA/gelatin 7/3 scaffold is more suitable for fibroblasts attachment and viability than the PLA or gelatin nanofiber alone. Thus fibroblast cultured on PLA/gelatin scaffold could be an alternative way to improve skin wound healing."
Materials
The current study aimed to evaluate the characteristics and the effects of degradation on the structural properties of Poly(lactic-co-glycolic acid) (PLGA)- and polycaprolactone (PCL)-based nanofibrous scaffolds. Six scaffolds were prepared by electrospinning, three with PCL 15% (w/v) and three with PLGA 10% (w/v), with electrospinning processing times of 30, 60 and 90 min. Both types of scaffolds displayed more robust mechanical properties with increased spinning times. The tensile strength of both scaffolds with 90-min electrospun membranes did not show a significant difference in their strengths, as the PCL and PLGA scaffolds measured at 1.492 MPa ± 0.378 SD and 1.764 MPa ± 0.7982 SD, respectively. All membranes were shown to be hydrophobic under a wettability test. A degradation behaviour study was performed by immersing all scaffolds in phosphate-buffered saline (PBS) solution at room temperature for 12 weeks and for 4 weeks at 37 °C. The effects of degradation were monitored b...
Electrospun nanofibrous structure: A novel scaffold for tissue engineering
Journal of Biomedical Materials Research, 2002
The architecture of an engineered tissue substitute plays an important role in modulating tissue growth. A novel poly(D,L-lactide-co-glycolide) (PLGA) structure with a unique architecture produced by an electrospinning process has been developed for tissue-engineering applications. Electrospinning is a process whereby ultra-fine fibers are formed in a high-voltage electrostatic field. The electrospun structure, composed of PLGA fibers ranging from 500 to 800 nm in diameter, features a morphologic similarity to the extracellular matrix (ECM) of natural tissue, which is characterized by a wide range of pore diameter distribution, high porosity, and effective mechanical properties. Such a structure meets the essential design criteria of an ideal en-gineered scaffold. The favorable cell-matrix interaction within the cellular construct supports the active biocompatibility of the structure. The electrospun nanofibrous structure is capable of supporting cell attachment and proliferation. Cells seeded on this structure tend to maintain phenotypic shape and guided growth according to nanofiber orientation. This novel biodegradable scaffold has potential applications for tissue engineering based upon its unique architecture, which acts to support and guide cell growth.
Electrospinning Production of PLLA Fibrous Scaffolds for Tissue Engineering
Nonwoven fibrous mats were produced in the process of solution electrospinning. Polymeric fibres generated in this process consist of poly(L-lactic) acid (PLLA), biodegradable and biocompatible polymer. Produced fibrous mats were examined by scanning electron microscopy and additionally degradation rate of fibrous material was investigated. Obtained fibres exhibit porous surface and fibre diameter varied from 200 nm to 1,2 m, depending on the process parameters. Low degradation rate of scaffold material was designed for long-term scaffold usage. The influence of solvent type and solution concentration as well as the solution flow rate, applied voltage and the setup geometry on the fibres morphology and diameter were examined and presented. The influence of polymer concentration on the solution viscosity was also evaluated. Further, the degradation rate of obtained fibres was investigated, as well as the influence of degradation process on surrounding environment. Materials produced in electrospinning process have potential application as long-term biodegradable scaffold for tissue engineering, especially in bone tissue, vascular tissue or cartilage tissue engineering.
Skin damage can occur for many reasons, including burns and injuries, which in extreme cases can even lead to death. Different methods such as electrospin-ning are used to produce scaffolds used in skin tissue engineering. Natural and synthetic polymers were used in this method. It was observed that the use of both natural and synthetic polymers gives better results for cell culturing rather than using of each material solely. In this study, scaffolds of poly(lactic-co-glycolic acid) and collagen were prepared using coating and common solvent methods. The characteristics of samples were evaluated through scanning electron microscopy, porosimetry, mechanical testing, degradation behavior, and in vitro assays. The mechanical and biocompatibility test results of the scaffold prepared by coating method were better than the other one. However, the degradation rate of the common solvent was nearly five times more than coating sample that leads to cytotoxicity in contact with the skin cells.