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1.
Porous bony scaffolds are utilized to manage the growth and migration of cells from adjacent tissues to a defective position. In the current investigation, the effect of titanium oxide (TiO2) nanoparticles on mechanical and physical properties of porous bony implants made of polymeric polycaprolactone (PCL) is studied. The bio-nanocomposite scaffolds are prepared with composition of nanocrystalline hydroxyapatite (HA) and TiO2 powder using the freeze-drying technique for different weight fractions of TiO2 (0 wt%, 5 wt%, 10 wt%, and 15 wt%). In order to identify the microstructure and morphology of the fabricated porous bio-nanocomposites, the X-ray diffraction (XRD), atomic force microscope (AFM) and scanning electron microscopy (SEM) are employed. Also, the biocompatibility and biodegradability of the manufactured scaffolds are examined by placing them in a simulated body fluid (SBF) for 21 days, their weight and pH changes are measured. The rate of degradation of the PCL-HA scaffold can be controlled by varying the percentage of its constituent components. Due to an increasing growth and activity of bone cells and the apatite formation on the free surface of the fabricated bio-nanocomposite implants as well as their reasonable mechanical properties, they have the potential to be used as a bone substitute. Additionally, with the aid of the experimentally extracted mechanical properties of the scaffolds, the vibrational characteristics of a beam-type implant made of the proposed porous bio-nanocomposites are explored. The results obtained from SEM image indicate that the scaffolds produced by the employed method have high total porosity (70%–85%) and effective porosity. The pore size is obtained between 60 and 200 μm, which is desirable for the growth and propagation of bone cells. Also, it is revealed that the addition of TiO2 nanoparticles leads to reduce the rate of dissolution of the fabricated bio-nanocomposite scaffolds.  相似文献   
2.
Biosilicate® glass-ceramic (BioS) offers an attractive choice for the manufacturing of scaffolds because of their high bioactivity, non-toxicity, bactericidal activity and biodegradability. Despite these positive properties, Biosilicate® scaffolds that have been developed so far show low fracture strength, limiting their clinical application. For this reason, our aim was to increase their strength through vacuum infiltration of F18 bioactive glass. First, we calculated the maximum attainable theoretical compressive strength of a scaffold using the Ryshkewitch and Ashby-Gibson models. We show that for a total porosity of 80 %, σ0 = 250 MPa, and n = 5 the compressive strength estimated by both models is approximately 4.5 MPa. Afterward, the Biosilicate scaffolds were prepared using the foam replica technique and recoated several times with a F18 glass slurry to eliminate surface defects. Scanning Electron Microscopy examination showed that the F18 indeed helped to remove surface defects and partially infiltrated the hollow struts, significantly increasing their mechanical integrity. The F18-BioS scaffolds exhibited a total porosity of 82 %, an average cell size of 525 μm, and compressive strength of 3.3 ± 0.3 MPa, which is close to the predicted value and significantly higher than those of sole BioS scaffolds of a similar structure (< 0.1 MPa). These values are within the range of commercial scaffolds based on Hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP), having a considerable advantage of being more osteoinductive, angiogenic, and highly bactericidal. The F18-BioS scaffolds developed in this work thus have high potential for odontology or craniofacial surgeries that do not involve high load–bearing conditions.  相似文献   
3.
Bone scaffolds provide a structural support for tissue development. Existing bone scaffolds are mainly characterized by complex porous designs whose shortcomings are a low level of permeability for growing tissue, and a difficult design customization. Scaffolds with nucleuses (rods or lattices) as basic elements should improve bone regeneration and enable higher design flexibility. In this paper, we present two new methods for building 3D geometrical models of personalized scaffolds, which are based on method of anatomical features. Methods are demonstrated in the case of scaffold for the mandible bone. This approach greatly reduces the designer effort and time, while enabling easy personalization of scaffolds’ shape and geometry.  相似文献   
4.
In this study, a new class of bioactive glass scaffolds was prepared through freeze casting method for bone tissue engineering applications. After analyzing the structural characteristics of the scaffolds, in vitro biological evaluations were assessed through monitoring alkaline phosphatase (AP) activity of osteoblast cells and soaking in simulated body fluid (SBF) for different time intervals. It was shown that the scaffolds consisted of bioactive glass plates with interconnected pores between them, aligned along the ice growth direction. The ability of the scaffolds for supporting the growth of human fetal osteoblastic cells (hFOB 1.19) was approved. Moreover, inductively coupled plasma-atomic emission spectrometry (ICP-AES) showed meaningful compositional changes of calcium, phosphorus and silicon in SBF solution, indicating the apatite forming ability of the scaffolds. The present investigation revealed that freeze casting could be an effective method for the preparation of highly bioactive scaffolds. In addition, the scaffolds proved to be highly compatible for the proposed works in vivo.  相似文献   
5.
《Ceramics International》2016,42(3):4507-4516
Three dimensional, highly porous, ZrO2 scaffolds coated by glass–ceramic derived from 45S5 bioglass were fabricated. The surface reactivity of 45S5 in aqueous solution was investigated as a function of the immersion time. The influence of the solid loading on the rheological behavior of 45S5 aqueous slips with ammonium polyacrylate (NH4PA) was studied; besides the effect of poly(vinyl)alcohol (PVA) on the relative viscosity was determined. The structure and microstructure of uncoated and coated ZrO2 scaffolds were characterized. The high ionic exchange capability of 45S5 was demonstrated by the pH rise, the significant weight loss and the amorphous calcium phosphate nucleation, upon its immersion in aqueous solution. The addition of PVA did not affect the dispersion properties of the 45S5 powder, which were basically controlled by its negative surface charge. 30 wt% 45S5 slips with 4 wt% PVA exhibited a yield stress and an adequate viscosity in the low shear rate range, to produce a bioglass coating into the ZrO2 scaffold. The glass-ceramic coating was distributed along the strut surfaces, forming a thin film without altering the porosity and the strut thickness of the original ZrO2 scaffold structure.  相似文献   
6.
Foam-like glass-ceramic scaffolds based on three different glass compositions (45S5 Bioglass and two other experimental formulations, CEL2 and SCNA) were produced by sponge replication and characterized from morphological, architectural and mechanical viewpoints. The relationships between porosity and compressive or tensile strength were systematically investigated and modelled, respectively, by using the theory of cellular solids mechanics or quantized fracture mechanics. Models results are in good agreement with experimental findings, which highlights the satisfactory predictive capabilities of the presented approach. The developed models could contribute to improve the rational design of porous bioceramics with custom-made properties. Knowing the scaffold recommended strength for a specific surgical need, the application of the models allows to predict the corresponding porosity, which can be tailored by varying the fabrication parameters in a controlled way so that the device fulfils the desired mechanical requirements.  相似文献   
7.
The present study reports foaming of polycaprolactone (PCL) and PCL nano- and micro-composites with dispersed hydroxyapatite (HA) particles by means of binary mixtures of supercritical CO2 (scCO2) and either ethyl lactate (EL) or ethyl acetate (EA) as plasticizer. The effect of the size and concentration of HA particles, as well as the effects of the plasticizer type and the incorporation route were investigated aiming to fabricate porous scaffolds with uniform morphology and controlled pore size distribution. For this purpose, foaming experiments were carried out by selecting two operating temperatures, 40 and 45 °C, and two soaking times, 1 and 17 h. Furthermore, a double step of depressurization was used to promote the development of a double-scale pore size structure in porous scaffolds useful for tissue engineering.The results of this study indicated that supercritical foaming of PCL and PCL–HA composites is enhanced when the selected operating temperature and time are 45 °C and 17 h, respectively. Furthermore, although both EL and EA plasticizers enhanced the low temperature foaming of the materials, we demonstrated that the route of incorporation of the plasticizer is a critical aspect for enhancing composite foaming and scaffold fabrication. From this point of view, the best results were achieved when EA was pre-mixed with the polymeric powder for preparing a dough for the foaming process.  相似文献   
8.
Gold nanoparticles (AuNPs) have arisen a lot of interest in the clinical realms of nanomedicine. Despite the large advances made in cancer research using AuNPs, their use in tissue engineering and regenerative medicine (TERM) is still in its infancy. Herein, it is discussed the properties, functionalization, and emerging use of AuNPs as a multifunctional and multimodal platform for drug delivery, phototherapy, diagnostic and cell imaging purposes. Moreover, the recent reports related to the ability of AuNPs to enhance stem cell differentiation for bone tissue engineering, to enhance the mechanical and adhesive properties of scaffolds and surface topography to guide cell behaviors are addressed.  相似文献   
9.
《国际聚合物材料杂志》2012,61(18):1108-1117
Abstract

In this study, capillary alginate gel (Capgel?), a collagen and alginate based self-assembling biomaterial, was used as a cellular scaffold for the treatment of ischemic, full-thickness dermal wounds in mice. Capgel? was synthesized using copper sulfate to form the initial sol before rinsing and stabilizing the patent capillary structures with carbodiimide chemistry. This crosslinked hydrogel was then injected into ischemic, full-thickness dermal wounds and analyzed via histology after 7 and 10 days to assess wound contracture, granulation bed tissue and vascular structures. Capgel? showed good resorbability and was well-invested with infiltrating host cells and vascular structures during and after resorption.  相似文献   
10.
Synthetic hydrogels can be used as scaffolds that not only favor endothelial cells (Ecs) proliferation but also manipulate the behaviors and functions of the Ecs. In this review paper, the effect of chemical structure, Young's modulus (E) and zeta potential (ζ) of synthetic hydrogel scaffolds on static cell behaviors, including cell morphology,proliferation,cytoskeleton structure and focal adhesion, and on dynamic cell behaviors, including migration velocity and morphology oscillation, as well as on EC function such as anti-platelet adhesion, are reported. It was found that negatively charged hydrogels, poly(2-acrylamido-2-methylpropanesulfonic sodium) (PNaAMPS) and poly(sodium pstyrene sulphonate)(PNaSS), can directly promote cell proliferation, with no need of surface modification by any cell-adhesive proteins or peptides at the environment of serum-containing medium. In addition, the Young's modulus (E) and zeta potential (ζ) of hydrogel scaffolds are quantitatively tuned by copolymer hydrogels, poly(NaAMPS-co-DMAAm) and poly(NaSS-co-DMAAm), in which the two kinds of negatively charged monomers NaAMPS and NaSS are copolymerized with neutral monomer, N,N-dimethylacrylamide (DMAAm). It was found that the critical zeta potential of hydrogels manipulating EC morphology, proliferation, and motility is ζcritical= -20.83 mV and ζcritical= -14.0 mV for poly(NaAMPS-co-DMAAm) and poly(NaSS-co-DMAAm), respectively. The above mentioned EC behaviors well correlate with the adsorption of fibronectin,a kind of cell-adhesive protein, on the hydrogel surfaces. Furthermore, adhered platelets on the EC monolayers cultured on the hydrogel scaffolds obviously decreases with an increase of the Young's modulus (E) of the hydrogels, especially when E > 60 kPa. Glycocalyx assay and gene expression of Ecs demonstrate that the anti-platelet adhesion well correlates with the EC-specific glycocalyx. The above investigation suggests that understanding the relationship between physic-chemical properties of synthetic hydrogels and cell responses is essential to design optimal soft and wet scaffolds for tissue engineering.  相似文献   
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