Papers by Keyword: Bone Tissue Engineering

Abstract: In the bone tissue engineering composite scaffolds with osteogenic potential are emerging as the new tool. Here, we investigated the graphene (GP), graphene oxide (GO) and Cissus quadrangularis (CQ) callus extract for their spontaneous osteoinductive potential. Electrospun poly ε-caprolactone (PCL) sheets were painted with varying combination GP, GO and CQ solutions as ink. The prepared PCL-GO, PCL-GO-CQ, PCL-GP and PCL-GP-CQ scaffolds were characterized for their physical, mechanical and biological properties. Addition of GO, GP, GO-CQ and GP-CQ to PCL enhanced roughness, wettability, Yield strength and tensile strength, biocompatibility .significantly. Presence of GO and CQ in PCL-GO-CQ scaffolds, while GP and CQ in PCL-GP-CQ scaffolds showed synergistic effect on the biocompatibility, Cell attachment,cell proliferation of human umbilical Wharton’s jelly derived mesenchymal stem cells (hUCMSCs) and their differentiation into osteoblasts by 21^st day in culture without osteogenic differentiation media or any growth factors. Same is confirmed by the Alizarin red S staining and Von kossa staining. The combination of PCL-GO-CQ scaffold prepared by novel paint method was found to be the most potential in bone tissue engineering.

Abstract: Natural bone is a complex material with well-designed architecture. To achieve successful bone integration and regeneration, the constituent and structure of bone-repairing scaffolds need to be flexible and biocompatible. HAp, as the main composition of bone minerals, has excellent biocompatibility, while CMC comprised of a three-dimensional network were high flexibility. Therefore, CMC/HAp composite have been attracted attention due to the development of bone tissue engineering. In this work, carboxymethyl cellulose (CMC)/hydroxyapatite (Ca₁₀(PO₄)₆(OH)₂; HAp) composite have been developed as three-dimensional scaffold for bone tissue engineering. Scanning electron microscopy revealed that the CMC/HAp composite have sheet-like structure. The amount of precipitated HAp of CMC/HAp composite was investigated using Thermogravimetric analysis. The amount of precipitated HAp in products prepared with 100 mg CMC was 49.8 wt%, while the amount of precipitated HAp in products prepared with 1000 mg CMC was 22.3 wt%. These results revealed that the amount of precipitated HAp in CMC/HAp composite was affected by CMC amount as prepared.

Abstract: The aim of this study was to present a direct fabrication technique of β-tricalcium phosphate (β-TCP) scaffolds by a bottom-up mask projection stereolithography (MPSL) technology, which provided an excellent control of the internal pore architecture. The debinding and sintering schemes of β-TCP were determined by TG-DSC analysis, the scaffolds with designed pore architecture were obtained. The physical properties of β-TCP scaffolds were investigated including pore morphology , size and pore distribution, the crystal phase and chemical composition of sintered β-TCP were measured. Results indicated that the β-TCP scaffolds fabricated with a pore size of 0.4-0.7mm, a porosity of 58.50% and an average compressive strength of 20.92MPa met the requirements of bone scaffold. The effectiveness of degradation and cell proliferation of β-TCP scaffold were also evaluated, the results showed that β-TCP scaffolds had some certain degradability and bioactivity, which may stimulates bone tissue repair and regeneration.

Abstract: Silk fibroin is a natural biodegradable polymer that has been demonstrated for use as scaffolds for bone tissue engineering. To improve the osteoconductivity and the osteoinductivity of silk fibroin scaffolds, ceramics were added. α-tricalcium phosphate (α-TCP) is the expected ceramic that useful for scaffolds for bone tissue engineering either alone or blended with silk fibroin. From the previous study, we evaluated the mechanical properties of three-dimensional porous silk fibroin/ α-TCP scaffolds and concluded that the scaffolds containing 8% (w/w) α-TCP exhibited the highest compressive modulus. The objective of this study was to evaluate the biological properties of three-dimensional porous silk fibroin/α-TCP scaffolds. The scaffolds were constructed using a solvent casting and salt leaching technique. The hybrid strain of degummed Thai silk fibroin, Nangnoi Srisaket 1 x Mor, was dissolved in hexafluoroisopropanol at 16% (w/v). α-TCP was incorporated to produce 4, 8, 12, and 16 wt% solution. Sucrose (particle size 250-450 μm; sucrose/silk fibroin = 8.5/1 w/w) was used as a porogen. Human gingival fibroblasts (passage 5) were cultured in these scaffolds. After 72 h, the biocompatibility of seeded scaffolds was evaluated under the inverted phase contrast microscopy. Cell proliferation was determined by DNA assays and scanning electron microscopy. The images from inverted phase contrast microscopy revealed the human gingival fibroblasts can be attached at the surface of scaffolds in all groups. The results from the DNA assays showed that the number of human gingival fibroblasts was increased as the culture period was prolonged but was not as the increasing of α-TCP. At 120 h, the scaffolds containing 8% (w/w) α-TCP exhibited the highest cell number. The scanning electron microscope images at 24, 72, and 120 h after cell culturing presented human gingival fibroblasts can be expanded well and exhibited the normal morphology. The results suggested that the scaffolds containing 8% (w/w) α-TCP may be a potential candidate for bone tissue engineering applications.

Abstract: It is well known that polyvinyl alcohol hydrogel-based (PVA-H) biomaterials are promising materials for damaged articular cartilage replacement, but their application for bone tissue engineering is restricted due to insufficient mechanical properties. Thus, to meet the demands of the bone substitute material, PVA-H are reinforced with hydroxyapatite (HAp) crystals. The current research is focused on the preparation of nanosized hydroxyapatite/polyvinyl alcohol (n-HAp/PVA) composite material that mimics the microstructure and mechanical properties of natural bone tissue. The aim of this work is to determine the impact of various technological parameters of n-HAp/PVA composite in situ synthesis on the chemical purity of final product. Obtained results confirmed that the main inorganic phase of the composite material is HAp with an average crystallite size of 20.39 nm, however β-tricalcium phosphate (β-TCP) and CaO phases are also present. Obtained results showed that it is possible to decrease the amount of potentially harmful by-products, e.g. CaO in the composite material from 1.57wt% to 0.32wt% by increasing the homogenization speed of starting suspension from 400 rpm up to 7000 rpm, though the main influence on the obtained products chemical purity has 5wt% polyvinyl alcohol aqueous solution. Based on the results, it is concluded that the combination of starting suspension stirring temperature, homogenization speed and homogenization time of 23°C, 7000 rpm and 2 min, respectively, allows to obtain nanocomposite with the lowest amount of impurities (HAp: 98.08wt%; β-TCP: 1.60wt%; CaO: 0.32wt%).

Abstract: Early establishment of angiogenesis is critical for bone tissue engineering. Recently, a technique was introduced, which is based on the idea of using axial vascularization of the host tissues in engineered grafts, namely the “intrinsic angiogenesis chamber” technique, which utilizes an artery and a vein to construct an AV-Bundle. The aim of this study was to evaluate the effect of varying scaffold architecture of calcium alkali orthophosphate scaffolds (CAOP), resulting from two different fabrication procedures, namely 3D printing (RP) or a Schwarzwalder-Somers replica technique (SSM), on angiogenesis in vivo when combining a microvascular technique with bioceramic scaffolds colonized with stem cells for bone tissue engineering. 32 adult female Wistar rats, in which critical size segmental discontinuity defects 6 mm in length were created in the left femur, were divided into 4 groups, group 1 received a RP scaffold colonized with rat stem cells after 7d of dynamic cell culture and an AV-Bundle (AVB), group 2 a SSM scaffold with rat stem cells after 7d of dynamic cell culture and an AVB, group 3 a RP control scaffold (without cells and AVB), group 4 a SSM control scaffold (without cells and AVB). After 3 and 6 months, angiomicro-CT after perfusion with a contrast agent, image reconstruction, histomorphometric and immunohistochemical analysis utilizing antibodies to collagen IV, vWF and CD-31 were performed. At 6 months, a statistically significant higher blood vessel volume%, blood vessel surface/volume, blood vessel thickness, blood vessel density and blood vessel linear density was observed with RP scaffolds with cells and AVB than with the other groups. At 6 mths, RP with cells and AVB displayed the highest expression of collagen IV (score 2.75), CD31 (score 2.75) and vWF (score 2.6), which is indicative of highly dense blood vessels. Both angio-CT and immunohistochemical analysis demonstrated that AVB is an efficient technique for achieving scaffold vascularization in critical size segmental defects after 3 and 6 months of implantation.

Abstract: Over the last decade there have been increasing efforts to develop adequate 3D scaffolds for bone tissue engineering from bioactive ceramics with 3D printing emerging as a promising technology. The overall objective of the present study was to generate a tissue engineered synthetic bone graft with homogenously distributed osteoblasts and mineralizing bone matrix in vitro, thereby mimicking the advantageous properties of autogenous bone grafts and facilitating usage for reconstructing segmental discontinuity defects in vivo. To this end, 3D scaffolds were developed from a silica containing calciumalkaliorthophosphate (code: GB9S14) utilizing two different fabrication processes, first a replica technique (SSM), and second 3D printing (RP). The mechanical and physical properties of the scaffolds (porosity, compressive strength, solubility) and their potential to facilitate homogenous colonization by osteogenic cells and extracellular bone matrix formation throughout the porous scaffold architecture prior to in vivo implantation were examined. To this end, murine osteoblastic cells (MT3T3-E1) were dynamically seeded and cultured for 7 days on both scaffold types under perfusion with two different concentrations of 1.5 and 3x10⁶ cells per ml. The amount of cells and extracellular matrix formed and osteogenic marker expression were evaluated using hard tissue histology, immunohistochemical and histomorphometric analysis. SSM scaffolds (SSMS) displayed a significantly greater total porosity (86.9%) than RP scaffolds (RPS) (50%), while RPS exhibited significantly more open micropores, greater compressive strength and silica release. RPS seeded with a 3x10⁶ cells per ml displayed greatest cell and extracellular matrix formation, mineralization and osteocalcin expression. In conclusion, RPS displayed superior mechanical and biological properties and facilitated generating a tissue engineered synthetic bone graft in vitro, which mimics the advantageous properties of autogenous bone grafts, by containing homogenously distributed terminally differentiated osteoblasts and mineralizing bone matrix and therefore is suitable for subsequent in vivo implantation for regenerating segmental discontinuity bone defects.

Abstract: Autografting is a bone replacement technique used in orthopedic surgery. Bone tissue engineering is a new technique that offers promise, and could help alleviate this risk. Bioceramics, biopolymers or composite can be fabricated for artificial bone scaffold and used for bone regeneration. This study used three types of biomaterials – hydroxyapatite (HA), fibroin, and chitosan – to form porous scaffold. HA and fibroin were prepared from natural materials. HA was synthesized from mollusk shell by wet chemical precipitation method, while silk fibroin was extracted from silk worm’s cocoons. The HA and fibroin were mixed in a variety of ratios along with a fixed amount of chitosan before fabricating composite porous scaffolds by freeze-drying. The resulting scaffolds were evaluated for biodegradability, biocompatibility, porosity pore morphology and mechanical property. The fabricated scaffolds had an interconnected porous structure with a pore size of 200-400 μm and porosity in a range of 93-95%. The average degradation rate of the scaffold in lysozyme was between 7-17% at 7 days. A biocompatibility test showed that the scaffold was non-cytotoxic, making it a good candidate for future bone tissue engineering applications.

Abstract: Novel silica-based bioactive glasses were successfully prepared by the sol-gel method. The optimized glass composition for fabrication of the scaffolds was (in mol.%) 60% SiO₂ – 30% CaO - 5% Na₂O - 5% P₂O₅ (60S30C5N5P). This composition was confirmed to develop a thick hydroxycarbonate apatite (HCA) layer in Simulated Body Fluid (SBF) after 7 days, as revealed by Fourier Transform Infrared Spectroscopy (FTIR), indicating the bioactive character of the scaffolds. The mesoporous nature of the glass structure allows the load of tetracycline and a sustained release of the drug in PBS during 7 days was measured.

Abstract: Novel photopolymerised composite hydrogels based on PEGDMA, maleic chitosan and maleic PVA were investigated for their suitability in bone tissue engineering applications. Initial swelling and compression studies revealed that the hydrogels permitted the retention of aqueous solution while still maintaining structural integrity. Promising cytotoxicity data was obtained during direct and indirect contact exposure of composite hydrogels to pre-osteoblast (MC3T3-E1) cells. Hybrid hydrogels displayed minimal cytotoxic properties and allow tailoring of mechanical properties by variation of the loading of the maleic component in the composite. Scanning electron microscopy and live-dead staining of composite hydrogels also revealed that maleic chitosan based gels supported the adhesion of MC3T3-E1 cells and may have potential as bone tissue engineering scaffolds.