Papers by Author: Xiang Cai Meng

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Authors: Jing Wang, Mu Qin Li, Xiang Cai Meng, Guang Wu Wen
Abstract: A composite of needle-like nano-Hydroxyapatite / silk fibroin (n-HA/SF) with strong interfacial bonding was successfully prepared from calcium chloride (CaCl2) and diammonium phosphate ((NH4)2HPO4) as starting materials of HA in the presence of SF powders dissolved in a ternary solvent system of CaCl2-C2H5OH-H2O (1:2:8 in molar ration) at 80 °C for 30 min prior to preparation of n-HA/SF composite. The n-HA crystals in the composite were poorly crystallized and uniformly distributed in the composite with a crystal size of 4~6 nm in diameter and 20~40 nm in length, which was smaller than that of pure nano-HA. Molecular interaction and strong chemical bonds were formed between n-HA and SF in the composite, which were revealed by Fourier transform infrared spectrometric analysis (FTIR). The synthetic n-HA/SF composite had a good homogeneity and preferential orientation along c-axis and would have a great potential for bone tissue engineering.
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Authors: Xiang Cai Meng, Kui Long Lv, Jiu Xing Zhang, Da Li Qu
Abstract: The purpose of this study is to examine the inhibitory effects of nano-HA on the caries-inducing properties of a four-organism bacterial consortium in vitro. A series of in vitro anticarious experiments have been carried out by using a continuous culture system. Streptococcus mutans, Streptococcus sanguis, Actinomyces viscosus, Lactobacillus rhamnosus have been chosen as the experimental bacteria. After 48 hours, the dental plaque surface structure is observed with the scan electron microscope and the bacterial colonization was evaluated on dental plaque. The results show that Spherical nano-HA and mixed nano-HA are proved to be effective in anticarious experiments, and especially spherical nano-HA is more striking. It is able to damage the formation of biofilms (dental plaque), postpone or end the process of acid generation of bacteria metabolism. After 7 days, the demineralization of the enamel has been detected by using TEM. The spherical nano-HA might have a remineralization to early caries to prevent and decrease caries.
251
Authors: Xiang Cai Meng, Xing Yi Li, Tao Wang
Abstract: The paper deals with a kind of new method of the electro-deposition on titanium by a cathode revolves. The depositing characteristic and mechanic were studied by scanning electron microscopy and X-ray diffraction. The experimental results show that the more fine uniformity and compact calcium phosphate bioactive coatings could be produced, compared with the conventional methods. The gradient Coating, which is fine inside and porous outside, could be obtained by controlling revolving velocity. The coating would transform to the hydroxyapatite after heat-treatment. After soaking in a simulated body fluid (SBF), nano-depositions were formed on the surface of the coating, then those particles would grow up needle-like, net-like, and an apatite-like layer could be observed finally. The gradient porosity coatings produced by cathode revolving electrochemical deposition would have high anti-dissolution and bioactive.
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Authors: Kui Long Lu, Xiang Cai Meng, Jiu Xing Zhang, Xing Yi Li, Mei Ling Zhou
Abstract: The objective of this study was to investigate the inhibitory effect of the synthetic nanohydroxyapatite (HA) on dental caries. The nano-HA was synthesized by using the depositing reaction of Ca (H2PO4)2. The artificial dental caries was made by using sour solution and inoculating Streptococcus mutans (S.mutans) to the Sprague-Dawley (SD) rat’s mouth respectively. After mineralization of solution of nano-HA for 10 days, the hardness of enamel was measured. The inhibitory effect of the synthetic nano-HA on dental caries was detected by gargling way to rinse the rat tooth with the solution of nano-HA in the animal test. Transmission electron microscopy (TEM) revealed that the dried HA particles were needle-like with ф5-20nm×60nm and the sintered HA particles were spherical with less than 100nm. The remineralized test indicated that the solution of nano-HA with different shapes enhanced the hardness of artificial caries and improved the remineralization of artificial caries. The animal test showed that the dried nano-HA had the inhibitory effect on dental caries. The good absorptive effect of the nano-HA on both the saliva protein and the glucans leads to the development of interventions that could reduce or modify bacterial colonization of tooth surfaces.
1538
Authors: Jing Wang, Hong Bo Li, Jing Gao, Xiang Cai Meng
Abstract: Chitosan fibers(CSf) andCaSiO3 were incorporated into a poly (L-lactic acid)/hydroxyapatite (PLLA/HA) matrix as reinforcements to prepare scaffold composites with adequate strength and high porosity for bone tissue engineering combined with emulsion freeze drying technique. The structural morphology of the composites was observed by scanning electron microscope (SEM). The porosity was tested by liquid substitute method. The mechanical property was measured. The effects of addition of CSf and CaSiO3 on composites were also discussed. Simulated body fluid (SBF) experiments were conducted to assess the bioactivity of the composites. The chemical components of resultants on surfaces after the immersion in SBF were analyzed by fourier transform infrared spectroscopy (FTIR). The results show that the composites with high connectivity have pore sizes of 100~250μm, a porosity of 60%~80%, compressive strength of 3.5~8.0MPa. In the SBF tests, Chitosan fiber reinforced PLLA/HA-CaSiO3 composite degraded stably, meanwhile, the formation of a layer of bone-like apatite on the surfaces of the samples indicated a good bioactivity. Studies suggest the feasibility of using CSf reinforced PLLA /HA-CaSiO3 composite for bone tissue engineering.
2055
Authors: Jing Wang, Mu Qin Li, Xiang Cai Meng, Guang Wu Wen
Abstract: Porous hydroxyapatite (HA) bioceramic matrix with interconnected ducts was obtained using a porogen burnout technique at 1200°C. The HA/silk fibroin (SF) composite scaffolds were developed with the SF sponges formed inside the pores and ducts of the bioceramics by first introducing HA/SF slurries into the pores and ducts followed by a freeze-drying process. Phase components and morphology of materials were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. Porosity was measured by Archimedean method. Compressive strength was also measured. The simulated body fluids (SBF) experiments were conducted to evaluate bioactivity. The results show that hydroxyapatite is the main phase compositions after sintering at 1200°C. The porosity of composite scaffolds reaches 70%~80%. The sizes of pores and ducts of HA matrix range from 150μm to 400μm and the pore sizes of SF sponges formed inside the macroporous structure of bioceramics are approximately 100μm,a structure favorable for bone tissue in-growth. The compressive strength of the composite scaffolds is greatly improved in comparison with that of HA matrix. In the SBF tests, a layer of randomly oriented apatite crystals form on the scaffold surface after sample immersion in SBF. The cell culture experiments show that the osteoblast cells are attached and proliferated on the surface of the composite scaffold, which suggest good bioactivity and cellular compatibility of the composite material.
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Authors: Jing Wang, Q.Z. Sun, Jing Gao, D.M. Liu, Xiang Cai Meng, Mu Qin Li
Abstract: Silk fibers were introduced into hydroxyapatite(HA)/chitosan(CS) matrix to prepare scaffold materials of bone tissue engineering with the adequate initial strength and improved cellular affinity using combination of in situ synthesis and freeze-drying technique. Chemical component was investigated using X rays diffraction (XRD) and Fourier transform infrared spectrum (FTIR). Structure and morphology of the composites were observed by scanning electron microscope (SEM). Porosity was tested by liquid substitution method. The mechanical properties of the composites were also measured. The simulated body fluid (SBF) and the cell culture experiments were conducted to assess biological properties of the composites. Results show that the composites with a pore size of 100~250μm have a porosity of 75%~90%and the maximum compressive strength of 5.7 MPa. The compressive strength of the composite is greatly improved in comparison with that of HA/CS matrix (4.6 MPa). In the SBF tests, a layer of randomly oriented apatite crystals form on the scaffold surface after sample immersion in SBF. The cell culture experiments show that the osteoblast cells are attached and proliferated on the surface of the composite, which suggests good bioactivity and cellular compatibility of the composite material. It is concluded that the composites have a promising prospect as bone tissue engineering materials.
557
Authors: Kui Long Lv, Jiu Xing Zhang, Xiang Cai Meng, Xing Yi Li
Abstract: The aim of this study is to describe the remineralization effect of the nano-HA toothpaste on artificial caries. The artificial dental caries is made using sour solution. The demineralized teeth specimen is put into five kinds of toothpaste solution respectively for 5 days and 10 days, which are: solution of containing needle like nano-HA, solution of containing spherical nano-HA, solution of general HA, fluorine sodium solution and physiological saline. The hardness of specimen is measured and the surface morphology is characterized by SEM. The remineralized test indicates that the nano-HA toothpaste can enhance the hardness of artificial caries and improve the remineralization of artificial caries. The SEM analysis shows that the cavities and defects of enamel surface are decreased and many mineral salts are sedimentated, which indicate that the nano-HA could promote remineralization for the demineralized enamel.
267
Authors: Kui Long Lv, Hai Wen Yuan, Xiang Cai Meng, Xing Yi Li
Abstract: The aim of this study is to describe the remineralization effect of the nano-HA on artificial caries. The artificial dental caries are made by using sour solution, and constructing an artificial mouth' plaque culture system in vitro respectively. The scanning electron microscope (SEM) and the optical microscope are used to observe the surface of enamel specimens. The effect of remineralization is assessed with the polarized light microscopy (PLM) and the confocal laser scanning microscope (CLSM) by measuring three lesion parameters (area, total and average fluorescence). The SEM analysis shows that the cavities and defects of enamel surface are decreased and many mineral salts are sedimentated, which indicate that the nano-HA could promote remineralization for the demineralized enamel. The inhibitory effect of the spherical nano-HA on dental caries is detected in the artificial mouth test. The CLSM shows that demineralization of enamel is reduced by adding the spherical nano-HA in artificial mouth. The results show that the spherical nano HA have a remineralization effect on the artificial dental caries dramatically, and can prevent and decrease caries.
576
Authors: Xiang Cai Meng, Xing Yi Li, Kui Long Lu
Abstract: The hydroxyapatite (HA) particle with different morphologies were prepared by adding a certain additive into Ca(H2PO4)2·H2O and controlling the bathing and sintering temperature, and the pure needle-like HA sol were obtained when the bathing temperature was 70°C. The experimental results show that the degree of crystallization of HA increase and the particles tend to accumulate with increasing of the drying and sintering temperatures. The particles of HA were spheroid, which diameters were of less than 100nm when they were sintered at the temperature of 700°C. The effect of nano-hydroxyapatite on remineralization of early enamel caries were studied too. The hardness of dismineralized enamel was increased when dismineralized enamel was remineralized by nano-hydroxyapatite. The SEM analysis shows that the interspace of enamel surface were decreased and the many mineral salts were sedimentated, which indicated that the nano-hydroxyapatie could promote remineralization for the dismineralized enamel.
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