1
|
Abstract
Background Blastocystis is ubiquitous presence in animals and humans worldwide and has a high level genetic diversity. The aim of this study was to conduct a summary of Blastocystis prevalence, subtypes (STs) in humans and animals in China and depict their distribution. Methods We searched for the articles related to epidemiology of Blastocystis in humans and animals throughout China which published from January 1, 1990, to July 31, 2019 in the following databases: PubMed, China National Knowledge Infrastructure (CNKI) and Wanfang database. The keywords were Blastocystis and one of the following ones: STs, subtypes, distribution, epidemiology, prevalence, infection, molecular, geographic, intestinal parasites, genetic diversity and characterization. Results In recent years, various molecular epidemiological studies have been carried out in some provinces/regions of China to identify subtypes of Blastocystis. Infants and young children, school students, hospitalized diarrhea patients, HIV/AIDS patients, tuberculosis patients, and cancer patients as respondents had been included. ST1–ST7 and ST12 were the main subtypes in Chinese population. Moreover, surveys of Blastocystis infection in animal were also conducted in some provinces of China. A variety of animals were investigated including pigs, cattle, sheep, yak, giant panda, and crested ibis (Nipponia nippon) with the main subtypes of ST1–ST8, ST10, ST12–ST14. Conclusions In recent years, some provinces/regions in China have conducted various molecular epidemiological studies to identify the Blastocystis subtypes. It is important to focus on new subtypes and mixed subtypes of infection, while increasing data on ribosomal alleles. We encourage the scientific community to start research on humans and surrounding animals (including domestic and wild animals) to better understand the possibility of Blastocystis transmission between humans and animals. We call for action among researchers studying intestinal parasitic diseases (Blastocystis), start drawing the subtype of Blastocystis and increase the subtype related to its clinical symptoms.
Collapse
Affiliation(s)
- Chao-Qun Ning
- Chinese Center for Disease Control and Prevention, National Institute of Parasitic Diseases, Shanghai, 200025, People's Republic of China.,Key Laboratory for Parasitology and Vector Biology, MOH of China, WHO Collaborating Center for Tropical Diseases, National Center for International Research On Tropical Diseases, Shanghai, 20025, People's Republic of China
| | - Zhu-Hua Hu
- Nanchang Center for Disease Control and Prevention, Nanchang, 330038, People's Republic of China
| | - Jun-Hu Chen
- Chinese Center for Disease Control and Prevention, National Institute of Parasitic Diseases, Shanghai, 200025, People's Republic of China.,Key Laboratory for Parasitology and Vector Biology, MOH of China, WHO Collaborating Center for Tropical Diseases, National Center for International Research On Tropical Diseases, Shanghai, 20025, People's Republic of China
| | - Lin Ai
- Chinese Center for Disease Control and Prevention, National Institute of Parasitic Diseases, Shanghai, 200025, People's Republic of China.,Key Laboratory for Parasitology and Vector Biology, MOH of China, WHO Collaborating Center for Tropical Diseases, National Center for International Research On Tropical Diseases, Shanghai, 20025, People's Republic of China
| | - Li-Guang Tian
- Chinese Center for Disease Control and Prevention, National Institute of Parasitic Diseases, Shanghai, 200025, People's Republic of China. .,Key Laboratory for Parasitology and Vector Biology, MOH of China, WHO Collaborating Center for Tropical Diseases, National Center for International Research On Tropical Diseases, Shanghai, 20025, People's Republic of China.
| |
Collapse
|
2
|
Hu ZH, Chen HH, Qian K, Ning CQ, Peng GH, Yu YF, Zhou XF, Chu YH, Xu D, Chen JX, Tian LG, Li H. [Prevalence and risk factors of Blastocystis hominis infections among AIDS patients in Nanchang City]. Zhongguo Xue Xi Chong Bing Fang Zhi Za Zhi 2020; 32:577-583. [PMID: 33325191 DOI: 10.16250/j.32.1374.2020208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To investigate the prevalence and risk factors of Blastocystis hominis infections among AIDS patients in Nanchang City. METHODS A cross-sectional questionnaire survey was conducted among AIDS patients in Nanchang City during the period between May and September, 2016. B. hominis infection was detected in patients'stool samples using a PCR assay, and the CD4+ T cell count was measured in subjects'blood samples. In addition, the risk factors of B. hominis infection in AIDS patients were identified using univariate and multivariate logistic regression analyses. RESULTS A survey was conducted in Nanchang City from May to September 2016. A total of 505 AIDS patients were investigated, and the prevalence of B. hominis infection was 4.16%. Univariate analysis revealed that B. hominis infection correlated with the occupation (χ2 = 8.595, P = 0.049), education level (χ2 = 14.494, P = 0.001), type of daily drinking water (χ2 = 10.750, P = 0.020), root of HIV infections (χ2 = 8.755, P = 0.026) and receiving anti-HIV therapy (χ2 = 23.083, P = 0.001) among AIDS patients, and multivariate logistic regression analysis identified daily direct drinking of tap water as a risk factor of B. hominis infections [odds ratio (OR) = 7.988, 95% confidential interval (CI): (1.160, 55.004)] and anti-HIV therapy as a protective factor of B. hominis infection [OR = 0.183, 95% CI: (0.049, 0.685)]. CONCLUSIONS The prevalence of B. hominis is 4.16% among AIDS patients in Nanchang City. Daily direct drinking of tap water is a risk factor, and anti-HIV therapy is a protective factor of B. hominis infection among AIDS patients living in Nanchang City.
Collapse
Affiliation(s)
- Z H Hu
- Research Base of the National Key Laboratory of Infectious Disease Prevention and Control, Key Laboratory of Animal Origin and Vector-borne Infectious Diseases of Jiangxi Province, Nanchang Center for Disease Control and Prevention, Jiangxi Province, Nanchang 330038, China
| | - H H Chen
- National Institute of Parasitic Disease, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Disease Research, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Key Laboratory of Parasites and Vector Biology, National Health Commission, China.,▵Co-first author
| | - K Qian
- Research Base of the National Key Laboratory of Infectious Disease Prevention and Control, Key Laboratory of Animal Origin and Vector-borne Infectious Diseases of Jiangxi Province, Nanchang Center for Disease Control and Prevention, Jiangxi Province, Nanchang 330038, China
| | - C Q Ning
- National Institute of Parasitic Disease, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Disease Research, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Key Laboratory of Parasites and Vector Biology, National Health Commission, China
| | - G H Peng
- Research Base of the National Key Laboratory of Infectious Disease Prevention and Control, Key Laboratory of Animal Origin and Vector-borne Infectious Diseases of Jiangxi Province, Nanchang Center for Disease Control and Prevention, Jiangxi Province, Nanchang 330038, China
| | - Y F Yu
- National Institute of Parasitic Disease, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Disease Research, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Key Laboratory of Parasites and Vector Biology, National Health Commission, China
| | - X F Zhou
- Research Base of the National Key Laboratory of Infectious Disease Prevention and Control, Key Laboratory of Animal Origin and Vector-borne Infectious Diseases of Jiangxi Province, Nanchang Center for Disease Control and Prevention, Jiangxi Province, Nanchang 330038, China
| | - Y H Chu
- National Institute of Parasitic Disease, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Disease Research, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Key Laboratory of Parasites and Vector Biology, National Health Commission, China
| | - D Xu
- Research Base of the National Key Laboratory of Infectious Disease Prevention and Control, Key Laboratory of Animal Origin and Vector-borne Infectious Diseases of Jiangxi Province, Nanchang Center for Disease Control and Prevention, Jiangxi Province, Nanchang 330038, China
| | - J X Chen
- National Institute of Parasitic Disease, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Disease Research, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Key Laboratory of Parasites and Vector Biology, National Health Commission, China
| | - L G Tian
- National Institute of Parasitic Disease, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Disease Research, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Key Laboratory of Parasites and Vector Biology, National Health Commission, China
| | - H Li
- Nanchang Municipal Health Commission, Jiangxi Province, China
| |
Collapse
|
3
|
Ning CQ, Kang JM, Li YT, Chen HH, Chu YH, Yu YF, Wu XP, Ai L, Chen JX, Tian LG, Liao QD. [Prevalence and risk factors of Blastocystis infections among primary school students in Jiangjin District, Chongqing City]. Zhongguo Xue Xi Chong Bing Fang Zhi Za Zhi 2020; 32:489-497. [PMID: 33185060 DOI: 10.16250/j.32.1374.2020189] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To investigate the prevalence and risk factors of Blastocystis infections among primary school students in Jiangjin District, Chongqing City. METHODS A cross-sectional questionnaire survey was conducted among students sampled from a primary school in Jiangjin District, Chongqing City on April, 2018, and their stool samples were collected for microscopic examinations, in vitro culture and PCR assays to analyze the prevalence of Blastocystis infections and subtype of the parasite. In addition, the risk factors of Blastocystis infections among primary school students were identified using univariate analysis and multivariate logistic regression analysis. RESULTS A total of 466 primary students were surveyed, and the subjects had a mean age of (9.81±1.66) years and included 236 males (50.64%) and 230 females (49.36%). The prevalence of Blastocystis infections was 15.24% (71/466) among the study students, and there was no significance difference in the prevalence between male and fe- male students (16.52% vs. 13.91%; χ2 = 0.616, P = 0.433). In addition, there was a significant difference in the prevalence of Blastocystis infections among grade 1 (6.35%, 4/63), grade 2 (5.17%, 3/58), grade 3 (21.74%, 15/69), grade 4 (25.30%, 21/83), grade 5 (10.19%, 11/108) and grade 6 students (20.00%, 17/85) (χ2 = 15.410, P = 0.009). There were four Blastocystis subtypes characterized (ST1, ST3, ST6 and ST7), in which ST6 was the most common subtype (45.07%, 32/71), followed by ST3 (25.35%, 18/71). Multivariate logistic regression analysis revealed that minority ethnicity [odds ratio (OR) = 4.259, 95% confidential inter- val (CI) : (1.161, 15.621)] and low maternal education level (primary school and below) [OR = 9.038, 95% CI: (1.125, 72.642)] were identified as risk factors of Blastocystis infection among primary school students in Jiangjin District, Chongqing City. CONCLUSIONS There is a high prevalence of Blastocystis infections detected among primary school students in Jiangjin District, Chongqing City, and ST6 and ST3 are predominant subtypes. Minority ethnicity and low maternal education level (primary school and below) are risk factors for Blastocystis infections in primary school students.
Collapse
Affiliation(s)
- C Q Ning
- National Institute of Parasitic Disease, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Disease Research, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Key Laboratory of Parasites and Vector Biology, National Health Commission, Shanghai 200025, China
| | - J M Kang
- Jiangjin District Center for Disease Control and Prevention, Chongqing City, China
| | - Y T Li
- National Institute of Parasitic Disease, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Disease Research, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Key Laboratory of Parasites and Vector Biology, National Health Commission, Shanghai 200025, China
| | - H H Chen
- National Institute of Parasitic Disease, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Disease Research, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Key Laboratory of Parasites and Vector Biology, National Health Commission, Shanghai 200025, China
| | - Y H Chu
- National Institute of Parasitic Disease, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Disease Research, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Key Laboratory of Parasites and Vector Biology, National Health Commission, Shanghai 200025, China
| | - Y F Yu
- National Institute of Parasitic Disease, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Disease Research, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Key Laboratory of Parasites and Vector Biology, National Health Commission, Shanghai 200025, China
| | - X P Wu
- National Institute of Parasitic Disease, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Disease Research, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Key Laboratory of Parasites and Vector Biology, National Health Commission, Shanghai 200025, China
| | - L Ai
- National Institute of Parasitic Disease, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Disease Research, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Key Laboratory of Parasites and Vector Biology, National Health Commission, Shanghai 200025, China
| | - J X Chen
- National Institute of Parasitic Disease, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Disease Research, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Key Laboratory of Parasites and Vector Biology, National Health Commission, Shanghai 200025, China
| | - L G Tian
- National Institute of Parasitic Disease, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Disease Research, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Key Laboratory of Parasites and Vector Biology, National Health Commission, Shanghai 200025, China
| | - Q D Liao
- Jiangjin District Center for Disease Control and Prevention, Chongqing City, China
| |
Collapse
|
4
|
Ning CQ, Ai L, Hu ZH, Chen JH, Tian LG. [Progress of researches on Blastocystis infections in humans and animals in China]. Zhongguo Xue Xi Chong Bing Fang Zhi Za Zhi 2020; 33:95-101. [PMID: 33660483 DOI: 10.16250/j.32.1374.2020101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Blastocystis is a unicellular, anaerobic, intestinal protozoan that infects humans and a variety of animals, which is widely prevalent across the world. Blastocystis infections have been detected in healthy populations, children, students, outpatients and inpatients, as well as diarrhea patients in China. High prevalence of Blastocystis infections has been reported in immunocompromised patients, and relatively high prevalence was seen in individuals living in Guangxi and Yunnan regions. Based on the small subunit ribosomal RNA (SSU rRNA) gene sequence, a total of 17 subtypes (ST1 to ST17) of Blastocystis have been characterized until now, among which ST1 to ST9 and ST12 infect humans and animals, and ST10 to ST17 only infect animals. In China, ST1 to ST3 are predominant human Blastocystis subtypes, and ST1/ST3, ST1/ST2 and ST2/ST3 mixed infections have been also identified. This review mainly describes the epidemiology and genotypes of Blastocystis in humans and animals in China.
Collapse
Affiliation(s)
- C Q Ning
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Key Laboratory of Parasite and Vector Biology, National Health Commission, Shanghai 200025, China
| | - L Ai
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Key Laboratory of Parasite and Vector Biology, National Health Commission, Shanghai 200025, China
| | - Z H Hu
- Nanchang Center for Disease Control and Prevention, Jiangxi Province, China
| | - J H Chen
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Key Laboratory of Parasite and Vector Biology, National Health Commission, Shanghai 200025, China
| | - L G Tian
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Key Laboratory of Parasite and Vector Biology, National Health Commission, Shanghai 200025, China
| |
Collapse
|
5
|
El-Ghannam A, Ning CQ, Mehta J. Cyclosilicate nanocomposite: a novel resorbable bioactive tissue engineering scaffold for BMP and bone-marrow cell delivery. J Biomed Mater Res A 2005; 71:377-90. [PMID: 15470721 DOI: 10.1002/jbm.a.30128] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Porous bioactive resorbable silica-calcium phosphate nanocomposite (SCPC) was prepared by a sintering technique. XRD analyses showed that the main crystalline phases of the SCPC are Na(3)CaPSiO(7) (clinophosinaite), beta-NaCaPO(4) (rhenanite), Na(2)CaSiO(4), and beta-quartz (SiO(2)). The clinophosinaite is a novel cyclosilicate bioactive mineral that enhanced the mechanical and bioactivity properties of the SCPC. TEM analysis showed that the grain sizes of the multiphase SCPC are in the nanometer scale. Moreover, the SCPC was engineered with nano- and microscale porosity. The SCPC had significantly higher compressive strength than porous hydroxyapatite (HA). FTIR analyses revealed the formation of biological hydroxyapatite layer on the SCPC surface after 4 days of immersion in SBF. When SCPC was loaded with rhBMP-2, it provided a superior release profile of biologically active rhBMP-2 compared to porous HA. Bone-marrow cells incubated with medium treated with the rhBMP-2 released from the SCPC-rhBMP-2 hybrid expressed significantly higher alkaline phosphatase activity than that expressed by cells incubated with media treated with rhBMP-2 released from HA-rhBMP-2. In addition, cells attached to the SCPC-rhBMP-2 hybrid produced mineralized extracellular matrix (ECM) and bone-like tissue that covered the material surface and filled pores in the entire thickness of the template after 3 weeks in culture. In contrary, cells attached to the HA-rhBMP-2 produced limited amount of unmineralized ECM after the same time period. Results of the study strongly suggest that the porous bioactive silica-calcium phosphate nanocomposite can serve as a delivery system for cells and biological molecules. The SCPC-rhBMP-2-marrow cell hybrid may serve as an alternative to autologous bone grafting.
Collapse
Affiliation(s)
- A El-Ghannam
- Center for Biomedical Engineering, Graduate School, University of Kentucky, Lexington, Kentucky 40506, USA.
| | | | | |
Collapse
|
6
|
Ning CQ, Mehta J, El-Ghannam A. Effects of silica on the bioactivity of calcium phosphate composites in vitro. J Mater Sci Mater Med 2005; 16:355-360. [PMID: 15803281 DOI: 10.1007/s10856-005-0635-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2004] [Accepted: 10/19/2004] [Indexed: 05/24/2023]
Abstract
In the present study, silica-calcium phosphate composites (SiO(2)-CaP composites) were developed by mixing the starting materials (SiO(2) and CaHPO(4)) in different ratios with the addition of 0.1% w/v NaOH solution. The phase composition of the SiO(2)-CaP composites was determined by XRD and FTIR. After thermal treatment at 350 degrees C/1 h and at 1000 degrees C/3.5 h; all SiO(2)-CaP composites composed of beta-quartz, alpha-cristobalite and beta-Ca2P2O7. The presence of calcium phosphate enhanced the transformation of beta-quartz into alpha-cristobalite at 1000 degrees C. SEM observation indicated favorable attachment and spreading of neonatal rat calvaria osteoblasts onto the surface of silica-rich SiO(2)-CaP composites. After attachment, these cells produced significantly higher amount of protein and expressed higher AP activity than cells attached to silica-poor samples. Results of the study suggested that the silica-based composites are more bioactive than calcium phosphate-based composites. Silica promoted the expression of osteoblast phenotype by both solution-mediated effect and direct interaction with the surface of the substrate.
Collapse
Affiliation(s)
- C Q Ning
- Center for Biomedical Engineering, University of Kentucky, Lexington, KY 40506, USA
| | | | | |
Collapse
|
7
|
El-Ghannam A, Ning CQ. Effect of bioactive ceramic dissolution on the mechanism of bone mineralization and guided tissue growthin vitro. J Biomed Mater Res A 2005; 76:386-97. [PMID: 16270343 DOI: 10.1002/jbm.a.30517] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A major objective of this research work was to evaluate the effect of bone cells on the dissolution-precipitation reaction in vitro. Rat bone marrow stem cells were seeded on silica-calcium phosphate nano composite (SCPC) with different chemical compositions and crystalline structures. Measurements of the Ca, P, Si, and Na concentrations in the tissue culture media using inductively coupled plasma indicated that bone marrow stem cells attached to the surface of SCPC did not affect the dissolution behavior of the material. However, bone marrow stem cells interfered with the back precipitation reaction and inhibited the formation of a calcium phosphate (Ca-P) layer on the material surface. Scanning electron microscope-energy-dispersive X-ray analyses showed that, in the absence of cells, a Ca-P layer formed on the material surface because of the dissolution-precipitation reaction. Bone cells attached to SCPC that contains high silica content absorbed significantly higher concentrations of medium Ca than cells attached to SCPC that contains low silica content. In conjunction with the absorption of high Ca concentration, attached bone marrow stem cells produced calcified nodules and mineralized extracellular matrix, indicating osteoblastic differentiation. Results of the study strongly suggest that the mechanism of bone mineralization at the interface with bioactive ceramics is mainly cell mediated and is enhanced by the absorption of critical concentrations of dissolved Ca and P. The silicon-rich phase also provided a guided cell adhesion and tissue growth in vitro. The enhanced bioactivity reactions and strong stimulatory effect on bone cell function are attributed to the modified crystalline structure of the SCPC material.
Collapse
Affiliation(s)
- A El-Ghannam
- Center for Biomedical Engineering, Wenner-Gren Research Laboratory, Graduate School, University of Kentucky, Lexington, KY 40506, USA.
| | | |
Collapse
|
8
|
Abstract
Silica and calcium phosphates (CaP) are the most important ingredients in bioactive materials that bond to bone and enhance bone tissue formation. In this study, silica-calcium phosphate (SiO2-CaP) composites were developed by powder metallurgy method, using silica (SiO2) and anhydrous dicalcium phosphate (CaHPO4) powders (CaP) in the ratios (wt%): 20/80, 40/60, 60/40 and 80/20. The effects of temperature and chemical composition on crystallization and phase transformation of the SiO2-CaP composites were evaluated by XRD and FTIR. Thermal treatment of the starting material suggested that CaHPO4 transforms into: gamma-Ca2P2O7 at 800 degrees C; beta-Ca2P2O7 at 1000 degrees C and alpha-Ca2P2O7 at 1200 degrees C. On the other hand, beta-quartz was the only detected phase after thermal treatment of silica in the temperature range 800-1200 degrees C. For all SiO2-CaP composites, SiO2 and CaP did not modify the crystallization behavior of each other when sintered in the temperature range 800-1000 degrees C. However, at 1200 degrees C, CaP promoted the transformation of gamma-quartz into alpha-cristobalite. Moreover, SiO2 stabilized beta-Ca2P2O7. The modifications in the crystallization behavior were related to ion substitution and formation of solid solutions.
Collapse
Affiliation(s)
- C Q Ning
- Center for Biomedical Engineering, University of Kentucky, Lexington, KY 40506, USA
| | | | | |
Collapse
|
9
|
Abstract
Sintering reactions and fine structures of the biocomposites prepared from powder mixtures of titanium ( alpha -Ti), hydroxyapatite (HA) and bioactive glass (BG) (SiO2-CaO-P2O5-B2O3-MgO-TiO2-CaF2) were investigated by X-ray diffraction and transmission electron microscopy. The results showed that complex reactions among the starting materials mainly depended on the initial Ti/HA ratios as well as the sintering temperatures. And the reaction could be expressed by the following illustrative equation: Ti+Ca10(PO4)6(OH)2-->CaTiO3+CaO+TixPy+(Ti2O)+(Ca4P2O9)+H2O.
Collapse
Affiliation(s)
- C Q Ning
- Center for Biomedical Engineering, Wenner Gren Research Laboratory, University of Kentucky, Lexington, KY 40506, USA.
| | | |
Collapse
|
10
|
Abstract
Traditionally, hydroxyapatite was used as a coating material on titanium substrate by various techniques. In the present work, a biocomposite was successfully fabricated from hydroxyapatite and titanium powders by powder metallurgy method. Bioactivity of the composite in a simulated body fluid (SBF) was investigated. Main crystal phases of the as-fabricated composite are found to be Ti2O, CaTiO3, CaO, alpha-Ti and a TiP-like phase. When the composite is immersed in the simulated body fluid for a certain time, a poor-crystallized, calcium-deficient, carbonate-containing apatite film will form on the surface of the composite. The time required to induce apatite nucleation is within 2 h. In addition, the apatite is also incorporated with a little magnesium and chlorine element. It is found that Ti2O has the ability to induce the formation of bone-like apatite in the SBF. And a dissolve of the CaO phase could also provide favorable conditions for the apatite formation, by forming open pores on the surface of the composite and increasing the degree of supersaturation of the SBF with respect to the apatite.
Collapse
Affiliation(s)
- C Q Ning
- School of Materials Science and Engineering, Harbin Institute of Technology, People's Republic of China.
| | | |
Collapse
|