Papers by Keyword: Tissue Engineering Scaffold

Abstract: Electrospinning is a versatile and efficient technique for fabricating nanofibrous tissue engineering scaffolds. However, problems such as small pore size of electrospun scaffolds have limited their applications for tissue regeneration. It is important to modify/improve existing electrospinning techniques for fully realizing the potential of both the electrospinning technology and electrospun nanofibrous scaffolds. To increase the pore size of scaffolds prepared by conventional electrospinning technology, in the present study, a hybrid fabrication technique by combining electrospinning with phase separation is utilized. Polymer solutions were made using mixed solvent of (a) DCM and DMF or (b) chloroform and DMF and electrospun fibers were deposited in ice water, ice methanol or liquid nitrogen. It was shown that for poly (ε-caprolactone) (PCL) scaffolds, the hybrid technique could maintain the nanofibrous structure for scaffolds and control the pore size in scaffolds. As compared with pore sizes in PCL scaffolds made by conventional electrospinning, pores were larger in PCL scaffolds produced by the hybrid technique.

Abstract: Scaffolds-based tissues engineering involves the combination of an artificial extracellular matrix (ECM), living cells, with high porosity and well connected pores that will provide suitable environment for cells. In this study, firstly, poly (caprolactone) (PCL)-based microspheres were synthesized and characterized. Bovine serum albumin (BSA) (0.04% w/v) was added into the microspheres produced from 5% (w/v) PCL concentration. BSA loaded microspheres were then incorporated into chitosan solution to fabricate porous scaffolds. The scaffolds were then characterized using different techniques.

Abstract: Although the degradation modeling of tissue engineering scaffold is in its initial step, it can direct the design, optimization of scaffold and help the application in medical case of illness. This paper analyzes the modeling methods and gives the speciality of every model which is put forward by researchers in China and abroad about the degradation of tissue engineering scaffold. These models are divided into micro scale, macro scale and two scale models based on the modeling scales. The recent research is belonging to single scale modeling. Some researchers abroad probed to two scale modeling. The future model is prospected in multi scale coupling macro, micro, and meta-macro model.

Abstract: Human dermis was used as a new source of raw material for tissue engineering scaffold fabrication. Three human dermal solutions were prepared from different fractions after centrifugation and denoted as DS-1, DS-2 and DS-3. Approximately, the ratios of sulfated GAGs to collagen were 0.03, 0.02 and 0.04 for DS-1, DS-2 and DS-3, respectively. Scaffolds from the human dermal solutions and the commercial bovine type I collagen (Sigma^®, St. Louis, MO, USA) were fabricated. The scaffolds were submerged in the normal culture medium and the calcium depositions were determined at day 1, 7 and 21. The highest calcium deposit was found in the scaffolds from type I collagen, the second were the scaffolds from DS-2, the third were the scaffolds from DS-1 and the lowest were the scaffolds from DS-3 for all time points. Histological sections stained with von Kossa stain explicitly exhibit the calcium depositions in the scaffolds. The calcium deposited in a manner according to the sulfated GAGs/collagen ratios of the scaffold materials. Calcium deposits are naturally incoperated into the collagen matrix of the human dermal solution-derived scaffolds. In bone tissue engineering, interpretation of experimental results should be careful of the spontaneous calcium deposition in scaffolds from collagen.

Abstract: Objective: Evaluate the biocompatibility of olfactory ensheathing cells (OECs) on the electrospun low-diameter silk fibroin scaffold (LD-SFS). Methods: 400 nm silk fibroin nanofibers were prepared by electrospinning technique and were observed by scanning electron microscope (SEM). The OECs were isolated and purified by the modified differential adherent velocity method. Then, the purified OECs were seed on the poly-L-lysine and electrospun silk fibroin scaffold. The nerve growth factor receptor (NGFR) p75 and glial fibrillary acidic protein (GFAP) were used to identify OECs by immunofluorescence staining. The MTT and flow cytometric assay were used to detect the proliferation and apoptosis effect of OECs on the different scaffolds. Results: The SEM showed that the average diameter of the fibers was about 400 nm and the nanofibers constituted a three-dimensional structure with porous network and smooth surface. The morphology of OECs on the LD-SFS group was similar to that on the poly-L-lysine (PLL) group. In addition, MTT and flow cytometric assay also showed that there was no significant difference between the two scaffolds in the proliferation and apoptosis activity. Conclusion: LD-SFS may serve as an ideal tissue engineering scaffold for the olfactory ensheathing cells.

Abstract: Silkworm silk has been recognized as a satisfactory biomaterial for long time due to its exceptional biocompatibility, biodegradability, mechanical properties etc. For example, silk fibers in the form of sutures have been used for centuries. The aim of this study is to discuss the potential usage of silk as the novel biomedical devices, such as blood vessels. In this study, cuit silks prepared from degummed raw silks were twisted as threads with four different yarn linear densities. A specific braiding machine was used to weave those threads into a tube. Subsequently two different groups of silk tubes were prepared. One was treated by ethanol and the other without. Thickness, porosity, mass per unit area of two groups of braided tubes were measured. Its mechanical properties were also studied. The influence of ethanol treatment and various yarn linear densities on its structural and mechanical properties was also studied. Results indicated that structural and mechanical properties of the tubes were significatly changed by the yarn linear densities and ethanol treatment. Conclusively, braided silk tube could be a potential blood vessel tissue engineering scaffold.

Abstract: Based on definitions of tissue engineering scaffold with defect bone, the constructing method for its exterior features was presented. First the pixels of picture at defect area were filled up and then the Boolean operations of filled pixels and original bone pixels were executed, and finally, all the area of filled pixels was 3D reconstructed to obtain the exterior features of scaffold. The 3D-reconstruction idea of the exterior features of scaffold and related projection and Boolean processes of model data for defect area were also analyzed.

Abstract: The paper describes β-TCP/DCHA and mineral phase structural bioceramics(CHA) as well as their 3-D structures, bioactivity, degradability and introducing new bone growth. FT-IR, XRD, SEM and Micro-CT were used to evaluate β-TCP/DCHA and mineral phase structural ceramics before and after implantation. Osteoblasts were immersed in the bioceramics and implanted in the rabbit femora. The experimental results showed that new bone grown in β-TCP/DCHA, and scaffolds were degraded with new bone formation and growth. The results indicated that β-TCP/DCHA was a better tissue engineering material. A kind of biomaterial (β-TCP/CHA) can be used for in situ formation or in vitro individuation formation. The experimental results indicated that β-TCP/CHA possessed better osteoblast affinity. Osteoblasts can adhere, proliferate and grow better on the material. The experiments in vivo showed the materials bonded with osseous tissue. The implants were degraded obviously after 6 months, and new bone replaced degradation materials.

Abstract: This study was aimed to estimate the cell-activity after culture of the cell-material composite and to evaluate the feasibility of constructing tissue-engineered bone using this novel material. Hollow HA mcirospheres (H-HAMs), porous PLA\HA tube，polyurethane plunger were prepared respectively. Mesenchymal stem cells (MSCs), which were derived from rat bone marrow were utilized as seed cells.Two different methods were used to integrate the seed cells and scaffold materials. Group A: H-HAMs were filled into porous HA tube, and porous polyurethane plungers were used to cover onto the ends of HA/PLA tubes as a whole, Then MSCs were cultured on the composite scaffolds; Group B: MSCs were compounded with H-HAMs completely first, then the pre-seeded composite of H-HAMs and cells was put into the porous PLA\HA tube which was then sealed with the polyurethane plunger. 1,3,5,7 and 9 days after cell-material composites were cultured, the growing status and adhesions of seed cells were observed. The viability of cells was quantified and increased over time in different methods, but was significantly higher in Group B after 9 days of culture. SEM detection revealed that more cells were detected on the PLA\HA tube and the outer layer of H-HAMs; growth of cells was more widespread and more cells were detected on H-HAMs in Group B. However, cells on H-HAMs seem to diminish over time in both groups. As a novel 3-D Hydroxyapatite scaffold, its H-HAMs are more easy to be integrated with seed cells, to be shaped according to clinical needs because of its semi-liquidity. However, the growth of cells especially in the inner core of the integrated material needs further research.

Abstract: The bone tissue engineering scaffold was developed by compounded the type I collagen with the porous scaffold of the sol-gel derived bioactive glass (BG) in the system CaO-P2O5-SiO2. The resultant porous scaffold was treated in supersaturated calcification solution (SCS) to form the surface layer of hydroxyl-carbonate-apatite (HCA) since the type I collagen possessed good biocompatibility and bio-absorbability, and also, the ability of inducting calcium phosphates to precipitated inside and outside the collagen fibers where the collagen fibers acted as bio-macromolecules template for formation of bone-like inorganic minerals in nature bone such as: octo-calcium phosphate (OCP), tri-calcium phosphate (TCP) and hydroxyl-carbonate-apatite (HCA). On the other hand, the sol-gel derived bioactive glass also played an important role in formation of the above bio-minerals owing to its serial chemical reactions with the body fluid. The in vitro study in supersaturated calcification solution SCS indicated that the surface of the porous scaffold was able to induce formation of bone-like HCA crystals on the pore walls of the scaffold which possessed satisfactory cells biocompatibility.