Papers by Keyword: Cell Proliferation

Abstract: Hydroxyapatite (HA) ceramic scaffolds are commonly used as bone graft substitutes. Design of such scaffolds is a challenge to improve biological properties and extend the applications of HA ceramics in the field of bone tissue engineering. In this work, we investigated the processing and the in vitro properties of HA ceramic scaffolds mimicking human trabecular bone architecture. Samples of human tibial trabecular bone were collected (University Hospital Center of Limoges) and scanned by X-Ray μ-computed tomography (μ-CT) to generate 3D model database. From this computer-aided design, HA ceramic scaffolds were shaped layer-by-layer by additive manufacturing using laser stereolithography (SLA). Then, green parts were sintered to obtain dense ceramic scaffolds. The shaped parts were compared to the model (wall thickness, size, and geometry of the porous network) using image analysis. A good agreement was found. Only small differences were detected due to a light overpolymerization or to some unprinted very small details that were not linked to a polymerized area of the previous layer. Due to part shrinkage during sintering a magnifying factor has to be applied to the scanned CAO model to match the real dimensions of the trabecular bone sample. Human mesenchymal stem cell (hMSC) cultures were performed to investigate the biological properties of these scaffolds (cell attachment and proliferation of hMSC). These preliminary biological evaluations show the good biocompatibility and cell adhesion of the HA substitute. This work evidences the efficiency of SLA to produce ceramic scaffold architectures mimicking that of the natural trabecular bone with promising biological behavior.

Abstract: In the present work, the surface of Ti-6Al-7Nb samples was patterned with Laser Induced Periodic Surface Structures in order to improve biocompatibility, increase tissue ingrowth and decrease bacterial adhesion and inflammatory response for applications in dental and orthopedic implants. Polished and sandblasted disks 10 mm in diameter were treated generating LIPSS under two different sets of parameters. The surface morphology and chemistry were investigated both by secondary electrons imaging, EDS analysis and Atomic Force Microscopy. Primary rat osteoblast culture (passage 2) was used to assess cell toxicity and biocompatibility. Alamar Blue assay was used to access cell viability and proliferation on day 1, 3 and 7. The difference between cell adhesion on polished and sandblasted surface as well as between polished and LIPSS-modified surface are described and discussed.

Abstract: The cell toxicity, cell proliferation and cell adhesion behaviors on the micro-arc oxidized surface of the conventional and large plastic deformed pure titanium (TA2) were studied. The results show that all samples have no cell toxicity. The cell proliferation ability on the surface of the large plastic deformed pure titanium (TA2) is better than that of the conventional pure titanium (TA2). The numbers of cells adhered on micro-arc oxidized surface of the large plastic deformed of pure titanium (TA2) are more than that of conventional pure titanium (TA2). And the distribution of the cells and cell morphologies are better than that of the conventional pure titanium (TA2). Results all above show that structure refinement of large deformation of pure titanium (TA2) has more significant improvement on the cell compatibility of the micro-arc oxidized modified films.

Abstract: In order to prepare the bone repair scaffold materials that could employ the sources of the injured bone, the bioactive HA and BMP-2 were added into the biomaterial PLLA. The four scaffold materials, PLLA, PLLA/HA, PLLA/BMP-2 and PLLA/HA/BMP-2 were prepared by electrospinning. The SEM results revealed that the morphology of the 7wt% PLLA fibers was better than the 5wt% PLLA fibers, and the HA nanoparticles were distributed uniformly in fibers. The calculated surface energy of the PLLA/HA/BMP-2 scaffold was higher compared with other three scaffolds, this result fit well with the result of MTT assay of the four scaffold materials, and the MTT assay showed that the MG63 cells on the PLLA/HA/BMP-2 scaffold material proliferated faster compared with the PLLA/HA or PLLA/BMP-2. It is logical to assume that PLLA/HA/BMP-2 scaffold material is a promising material for bony tissue repair.

Abstract: This work aims to investigate the influence of surface conditioning of porous Ti for enhancing its biological activity, as assessed by in vitro stem cell testing. Porous Ti samples with an average porosity of 32% were processed by Powder Metallurgy with dextrin as a space holder. The samples were subjected to H₂O₂ treatment to form an enhanced TiO₂ film, followed by a heat treatment at 400°C and 600°C aiming to the crystallization of the as-formed amorphous titanium oxide. Samples characterization was performed by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR) and X-Ray Diffraction (XRD). The treated surfaces revealed to be made of both anatase and rutile TiO₂, with groove–shaped structure and cracks on the surface of the TiO₂ film. The intrinsic biocompatibility of the chemically modified porous Ti surfaces was assessed in vitro. In our cell culture tests, stem cells were found to attach and proliferate better on the chemically treated Ti surfaces compared to the control untreated Ti surfaces.

Abstract: The nitrogen-doped diamond-like carbon film was prepared on Ti6Al4V alloy by using plasma enhanced chemical vapor deposition (PECVD) technique,and its biocompatibility was studied.The surface morphology,chemical composition and contact angle were measured by scanning electron microscope (SEM),X-ray photoelectron spectroscopy(XPS),Raman Spectrometer and contact angle measuring device. Finally, the proliferation rate and cellular morphology of 3T3-E1 osteoblast cells on different sample surfaces were tested and Image J software was used to statistically analyze the count of the adhered cells. The results showed that cell adhesion and proliferation were significantly (P<0.05) increased on nitrogen-doped diamond-like carbon films , which illustrated that N doping improved the biocompatibility of DLC films. This finding has potential clinical application value to modify titanium alloy for new bone formation.

Abstract: We cloned a new serine protease gene from the marine annelid, Arenicola cristata by rapid amplification of cDNA ends. The full-length cDNA of 901bp contained an open reading frame of 774bp encoding 258 amino acids. Sequence analysis of the deduced amino acids indicated that this protease belonged to serine protease family and contained highly conserved sequence GDSGGP. An expression vector, harboring the mature peptide of Arenicola cristata protease, was constructed and transformed into E.coli. The purified recombinant protein could inhibit proliferation of cancer cells in a dose-dependant way and induce apoptosis. These results indicated that the recombinant protease of Arenicola cristata, as a new member of serine protease family, might be valuable in developing anti-tumor agents.

Abstract: The aim of the present study was to evaluate the cell viability and angiogenic differentiation of rat bone marrow mesenchymal stem cells (rBMSCs) stimulated by a new fabricated nagelschmidititebioceramic. The Ca₇Si₂P₂O₁₆bioceramics (CSP) were extracted with L-DMEM for 72h. The extracts were analyzed byInductively Coupled Plasma optical emission Spectrometry (ICP-OES) to determine the elemental concentrations of calcium, siliconand phosphorus (Ca, Si and P). MTT assay was conducted to evaluate the cell viability of original extracts. Gene expression of endothelial specific markers including vWF and CD31 was assayed forBMSCs cultured in original extracts on day 3 and 10 to determine the angiogenesis.The results showed that the concentration of Ca, P and Si ions released from CSP ceramic were 112.0mg/L, 62.0mg/L and 19.8mg/L respectively, which were much more than β-TCP and control group. CSP also showed more significant cell viability and higher exression level of vWF and CD31 when rBMSCs were cultured with its extracts. This study indicated that this new bioceramics are promising bioactive materialsfor bone tissue regeneration.

Abstract: Objective: p53, a tumor suppressor gene, is one of the hotspots in the world of the biomedical field. Mutation of p53 gene, which is found in approximately 50% of human cancers, is a key event in carcinogenesis. This project aims to investigate the new characteristics of two p53 mutants, p53-W248 and p53-H175, in MCF-7 cells, so as to provide the experimental basis for understanding the functional alternations of mutant p53. Methods: In this study, MCF-7 cells transfected with p53-H175 or p53-W248 plasmids were used as experimental group and the MCF-7 cells transfected wild type p53 plasmid were used as control group. Then the biological effects at the cellular level were investigated using 3-(4.5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay, flow cytometry analysis and cell scratch test. Results: MTT assay showed that p53-W248 might promote cell proliferation in MCF-7 cells. The results of flow cytometry indicated that no significant effect on cell cycle progression and cell apoptosis by p53-H175 or p53-W248 in cells. The cell scratch test showed that p53-H175 could increase the ability of cell migration. Conclusion: p53-H175 could lead to the promotion of tumor cell migration, while p53-W248 may promote tumor cell proliferation. p53-H175 and p53-W248 might have acquired some new characteristics of oncogenes.

Abstract: The present study was designed to investigate the effects of porcine collagen peptides on biological behavior of PC12 cells, the Amino acid composition of porcine collagen peptides was analyzed using Amino Acid Analyzer, the contact angles were measured with a goniometer, and after treatment with porcine collagen peptides, the impact of peptides on cells proliferation and differentiation was evaluated using MTT assay and Real-time PCR respectively. porcine collagen peptides is found to contain mainly Gly, Pro and Hyp, the contact angles of porcine collagen peptides surfaces were approximately 23.3°. MTT Results revealed that collagen peptides promoted PC12 cells proliferation at the given concentrations with its maximum effect at the concentration of 0.2 mg/ml (P<0.01), Real-time PCR Results revealed the poricine collagen peptides had no influence on the expression of specific neuronal marker β3-tubulin. Results of this study suggest that based on their bioactivity, porcine collagen peptides could be promising candidates for biomaterials.