Biomedical subjects

Yingjun Wang

Publications and source records attributed to Yingjun Wang.

11 recordsLinked to original sources

PubMed2007

Control of crystallinity of hydrated products in a calcium phosphate bone cement.

In this study, a calcium phosphate cement (CPC), consisting of partially crystallized calcium phosphate (PCCP), was synthesized. X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR) and scanning electronic microscope (SEM) were used to characterize the cement. The results showed that by changing the ratio of amorphous calcium phosphate (ACP) to PCCP in the cement, hydrated products of controllable crystallinity were obtained. With increase in the relative amount of PCCP, the hydrated products changed gradually from very poor crystallinity with little needle-like hydroxyapatite (Hap) crystallites to relatively high crystallinity with more needle-like Hap crystallites; the compressive strength of the cement increased, and the degradation of the cement decreased. The cement was implanted into the tibia tubercle of healthy mature Zelanian white rabbits and the histological specimens were obtained after 4 and 16 weeks of implantation. The result revealed that this bone cement was biocompatible and showed very early osteoconductive properties. Thus, the CPC has potential for use in orthopedic surgery for filling non- load-bearing bone defects.

Animals↗

PubMed2007

Characteristic comparison of bioactive scaffolds based on polyhydroxyalkoanate/bioceramic hybrids.

In this study, bioactive hybrid scaffolds were prepared by combining poly(beta-hydroxybutyrate-co-beta-hydroxyvalerate) (PHBV) with three kinds of bioceramics, which are sol-gel bioglass (SGBG), tricalcium phosphate (TCP), and hydroxyapatite. The bioactivity and biodegradation of various scaffolds were analyzed with simulated experiments in vitro by immersing the scaffolds into simulated body fluid to evaluate their biomineralizing ability. The changes of the surface components and structures were determined by FTIR, XRD, and SEM analyses. Cell cultures and observation were made in vitro to assess the proliferation of osteoblast on these scaffolds. The results show that there might be ion exchanges and biodegradation reactions occurring between the hybrids and simulated body fluid solution, which result in the weight loss of the scaffolds and the pH changes in solution. An obvious biomineralized deposit layer was formed on the surface of the PHBV/SGBG and PHBV/TCP scaffolds, which was determined to be the bonelike crystalline hydroxyl-carbonate-apatite. The experiments on cell culture show that osteoblast could grow and proliferate on the bioactive hybrid scaffolds.

Animals↗

PubMed2007

Self-setting properties of a beta-dicalcium silicate reinforced calcium phosphate cement.

Beta-dicalcium silicate was used to reinforce the injectable calcium phosphate cement (iCPC) for the first time in this study. The influence of the content of beta-dicalcium silicate on the mechanical properties, setting time, rheological properties, injectability, phase evolution, microstructure, and biodegradability of iCPC was systematically investigated. The results demonstrated that the addition of 8 wt % beta-dicalcium silicate obviously enhanced the compressive strength of the CPC from 26.5 to 47.5 MPa, and did not significantly influence the biodegradability, setting time, injectability, phase evolution, and microstructure of the CPC. The beta-dicalcium silicate-reinforced iCPC with relatively high mechanical property should have potential prospects for the wider applications in surgery such as orthopedics, oral, and maxillofacial surgery.

Bone Cements↗

PubMed2006

An inorganic carbon transport system responsible for acclimation specific to air levels of CO2 in Chlamydomonas reinhardtii.

Many photosynthetic microorganisms acclimate to CO(2) limited environments by induction and operation of CO(2)-concentrating mechanisms (CCMs). Despite their central role in CCM function, inorganic carbon (Ci) transport systems never have been identified in eukaryotic photosynthetic organisms. In the green alga Chlamydomonas reinhardtii, a mutant, pmp1, was described in 1983 with deficiencies in Ci transport, and a Pmp1 protein-associated Ci uptake system has been proposed to be responsible for Ci uptake in low CO(2) (air level)-acclimated cells. However, even though pmp1 represents the only clear genetic link to Ci transport in microalgae and is one of only a very few mutants directly affecting the CCM itself, the identity of Pmp1 has remained unknown. Physiological analyses indicate that C. reinhardtii possesses multiple Ci transport systems responsible for acclimation to different levels of limiting CO(2) and that the Pmp1-associated transport system is required specifically for low (air level) CO(2) acclimation. In the current study, we identified and characterized a pmp1 allelic mutant, air dier 1 (ad1) that, like pmp1, cannot grow in low CO(2) (350 ppm) but can grow either in high CO(2) (5% CO(2)) or in very low CO(2) (<200 ppm). Molecular analyses revealed that the Ad1/Pmp1 protein is encoded by LciB, a gene previously identified as a CO(2)-responsive gene. LciB and three related genes in C. reinhardtii compose a unique gene family that encode four closely related, apparently soluble plastid proteins with no clearly identifiable conserved motifs.

Acclimatization↗

PubMed2006

Improvement in hydrophilicity of PHBV films by plasma treatment.

Poly(3-hydroxybutyrate-co-hydroxyvalerate) (PHBV) films were prepared by the solvent cast method. Oxygen and nitrogen plasma treatment were used to improve the hydrophilicity of the surface of PHBV films. The surface properties were characterized by contact angle measurement and X-ray photoelectron spectroscopy (XPS). The water contact angle of PHBV films decreased after plasma treatment, which suggested that the surfaces became more hydrophilic. The effects of exposure time, plasma generating power, and chamber pressure on water contact angle were investigated. Although the decrease of contact angle with both plasma treatments was similar, the change of PHBV surface structure was different. XPS analysis showed that the oxygen content and the ratio of O/C increased markedly after oxygen plasma treatment, while after nitrogen plasma treatment, the surface was enriched with nitrogen atoms. Furthermore, it was found that C-O and C-C bonds were broken with both plasma treatment, while different new bonds were formed, that is, COOH (for oxygen plasma), and C-N, C=N, and amide bonds (for nitrogen plasma) have been generated after plasma irradiation. Dog bone marrow stromal cell culture studies showed that cells grew better on the plasma treated surface. These results demonstrate potentiality of this method for grafting useful component in future tissue-engineering applications.

Animals↗

PubMed2006

[Recent development of computer-aided tissue engineering].

OBJECTIVE: To introduce the recent advances of the application of computer technology in tissue engineering. METHODS: The recent original articles related to computer technology, medical image technology, computer-aided design, the advanced manufacture technology were summarized and systematically analyzed. RESULTS: Computer-aided tissue engineering is a new field on tissue engineering. It is the future direction of tissue engineering study. This article reviews recent development of medical CT/MRI scanning, three-dimensional reconstruction, anatomical modeling, computer-aided design, computer-aided manufacturing, rapid prototyping, RP manufacturing of tissue engineering scaffolds and computer-aided implantation. CONCLUSION: Computer-aided tissue engineering can be used in scaffolds design and fabrication, computer-aided artificial tissue implantation. It is a new field on tissue engineering.

Computer-Aided Design↗

PubMed2005

Application research of plasma-enhanced electrochemical surface ceramic-coating technology on titanium implants.

Plasma electrochemical surface ceramic coating (PECC) is an enhanced electrochemistry technique accomplished by means of plasma arc discharge in an electrolyte medium obtain coating structures on valve-metal surfaces. Oxide films of titanium obtained by PECC in the electrolyte of sodium phosphate were investigated. The film was composed mainly of TiO2 in the form of anatase and rutile and enriched with Na and P elements on their surfaces. Their apatite-inducing ability was also evaluated in a simulated body fluid (SBF). When immersed in SBF for over 30 days, an oriented hydroxy-carbonate-apatite was induced on the surface of the films, which suggests the PECC-treated titanium has the promising positive biological response.

Biomimetic Materials↗

PubMed2004

[Development of biodegradable and bioabsorbable bone-repaired materials].

This paper reviews recent work on biodegradable and bioabsorbable materials, including macromolecular, inorganic, and compound materials which have been used as bone-repaired devices. The properties and uses of poly(lactic acid), chitin and tricalcium phosphate are expounded. At the same time, we discuss the trend in the development of biodegradable and bioabsorbable bone-repaired materials. In our opinion, the development of biodegradable and bioabsorbable bone-repaired materials forcuses on the composite of different materials, especially the composite of BMP and MSCs; on the improvement of the mechanical properties of materials; and on the search for new suitable materials.

Absorbable Implants↗

PubMed2003

[Studies of poly(vinyl alcohol)/hydroxylapatite hydrogels compounds for cartilage implantation].

The structures and properties of polyvinyl alcohol (PVA)/hydroxylapatite(HA) composites were investigated. The components and processing conditions were studied for preparation of optimum compound hydrogels with good lubricating feature and high bioactivity. The properties, such as stretch strength, compress strength, friction, compress stress relaxation of various compound hydrogels were compared. The micro-morphology of PVA hydrogels and PVA/HA hydrogels were investigated by use of SEM. It was found that the addition of HA could improve the lubricating feature and mechanical strength of hydrogels, and its compress stress relaxation properties were closer to those of natural cartilages.

Biocompatible Materials↗

PubMed2003

[Review of poly(vinyl alcohol) hydrogel and its compounds in the application of artificial cartilage materials].

Poly(vinyl alcohol) (PVA) hydrogel is a kind of material which has excellent biocompatibility and mechanical properties. In this paper, the researches and developments of PVA hydrogel preparation and the modifications of PVA with other material were introduced. The potential for the use of PVA hydrogels as implant materials in cartilage reparation was reviewed.

Biocompatible Materials↗

PubMed2002

[Effect of moulding and extruding conditions on mechanical properties of poly(D,L-lactide) and MDI chain-extending poly(D,L-lactide)/hydroxyapatite composite].

In this paper, poly(D,L-lactide) (PDLLA), MDI chain-extending poly(D,L-lactide) (PDLLA/MDI) and MDI chain-extending poly(D,L-lactide)/hydroxyapatite composite (PDLLA/HA/MDI) were prepared respectively and the effects of moulding and extruding conditions on their mechanical properties were also investigated. At the optimal conditions, bending strength of PDLLA and PDLLA/MDI is 35.1 MPa and 51.3 MPa, respectively, and their bending modulus is 2413.6 MPa and 1830.9 MPa, respectively. Bending strength of PDLLA/HA and PDLLA/HA/MDI is 31.2 MPa and 55.4 MPa, respectively, and their bending modulus is 1735.0 MPa and 2068.5 MPa, respectively. These results have shown that the mechanical properties of PDLLA/MDI and PDLLA/HA/MDI have enhanced significantly by MDI chain-extending.

Biocompatible Materials↗