Wei Zhang

Publications (29)106.33 Total impact

• Article: Comparison of minimally invasive percutaneous plate osteosynthesis with open reduction and internal fixation for treatment of extra-articular distal tibia fractures.

  Jian Zou, Wei Zhang, Chang-Qing Zhang
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  ABSTRACT: INTRODUCTION: Minimally invasive percutaneous plate osteosynthesis (MIPPO) has become a widely accepted technique to treat distal tibia fractures. However, it remains unclear whether this strategy of biological osteosynthesis with a bridge plate is superior to that of absolute stability with traditional open reduction and internal fixation (ORIF). METHODS: In this pilot study, patients with distal tibia fractures, aged from 18 years to 60 years, were included from October 2005 to June 2007. Patients were randomly assigned to a closed group (the patients were treated by MIPPO) or an open group (the patients were treated by traditional ORIF) before they were categorised by AO fracture type. Wound healing was assessed at 2 weeks, 4 weeks, and 3 months postoperatively. Follow-up was performed once a month until the fractures achieved clinical union based on the standard criterion (pain-free full weight-bearing). Evaluation was performed for ankle range of motion, limb rotation, fracture healing, and radiographic alignment. RESULTS: Forty-two patients were randomised to the open group and 52 to the closed group. According to AO/OTA classification, fractures were classified as Types A (55.3%), B (25.5%), and C (9.1%). The median follow-up time was 14.0 months for the open group and 15.0 months for the closed group. There was no significant difference between the groups in healing time for Type A and Type B fractures; however, for Type C fractures, there was a trend towards shorter healing time in the closed group compared with the open group. CONCLUSIONS: Our findings suggest that the strategy of biological osteosynthesis with a bridge plate might be superior to that of absolute stability for treating Type C tibia fractures. Further studies are needed to confirm our findings.
  Injury 03/2013; · 1.98 Impact Factor
• Article: Mechanical properties and crystallization behavior of hydroxyapatite/poly(butylenes succinate) composites.

  Wenmin Guo, Yihe Zhang, Wei Zhang
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  ABSTRACT: Biodegradable synthetic polymers have attracted much attention nowadays, and more and more researches have been done on biodegradable polymers due to their excellent mechanical properties, biocompatibility, and biodegradability. In this work, hydroxyapatite (HA) particles were melt-mixing with poly (butylenes succinate) (PBS) to prepare the material, which could be used in the biomedical industry. To develop high-performance PBS for cryogenic engineering applications, it is necessary to investigate the cryogenic mechanical properties and crystallization behavior of HA/PBS composites. Cryogenic mechanical behaviors of the composites were studied in terms of tensile and impact strength at the glass transition temperature (-30°C) and compared to their corresponding behaviors at room temperature. With the increase of HA content, the crystallization of HA/PBS composites decreased and crystallization onset temperature shifted to a lower temperature. The diameter of spherulites increased at first and decreased with a further HA content. At the same time, the crystallization rate became slow when the HA content was no more than 15wt% and increased when HA content reached 20wt%. In all, the results we obtained demonstrate that HA/PBS composites reveal a better tensile strength at -30°C in contrast to the strength at room temperature. HA particles with different amount affect the crystallization of PBS in different ways. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.
  Journal of Biomedical Materials Research Part A 01/2013; · 2.63 Impact Factor
• Article: Surface and Tribological Behaviors of the Bio-inspired Polydopamine Thin Films in Dry and Wet Conditions.

  Wei Zhang, Fut K Yang, Yougun Han, Ravi Gaikwad, Zoya Leonenko, Boxin Zhao
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  ABSTRACT: Dopamine is a "sticky" biomolecule containing the typical functional groups of mussel adhesive proteins. It can self-polymerize into a nanoscale thin film on various surfaces. We investigated the surface, adhesion, friction and cracking properties of polydopamine (PDA) thin films for their effective transfer to functional devices and biocompatible coatings. A series of surface characterizations and mechanical tests were performed to reveal the static and dynamic properties of PDA films coated on glass, polydimethylsiloxane (PDMS), and epoxy. We found that PDA films are highly hydrated in wet conditions because of their porous membrane-like nano-structures and hydrophilic functional groups. Upon dehydration, the films form cracks when they are coated on soft substrates due to internal stresses and the large mismatch in elastic modulus. The adhesive pull-off force or the effective work of adhesion increased with the contact time, suggesting dynamic interactions at the interface. A significant decrease of friction forces in water was observed on all three material surfaces coated with PDA; thus, the film might serve as a water-based lubrication coating. We attributed the different behavior of PDA films in air and in water to its hydration effects. These research findings provide insights into the stability and mechanical and adhesive properties of the PDA films, which are critical for their applications.
  Biomacromolecules 01/2013; · 5.48 Impact Factor
• Article: Poly(AAc-co-MBA) Hydrogel Films: Adhesive and Mechanical Properties in Aqueous Medium.

  Dhamodaran Arunbabu, Hamed Shahsavan, Wei Zhang, Boxin Zhao
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  ABSTRACT: Poly(Acrylic acid-co-N, N'-Methylenebisacrylamide) hydrogel films were synthesized by copolymerizing acrylic acid (AAc) with N, N`-methylenebisacrylamide (MBA) as a crosslinker via photo polymerization in the spacing confined between two glass plates. NMR spectroscopy was utilized to determine the cross-linking density. We found that the cross-linking density determined by NMR is higher than that expected from the feed concentrations of cross-linkers, suggesting that MBA is more reactive than AAc and the heterogeneous nature of the cross-linking. In addition to the swelling tests, indentation tests were performed on the hydrogel films under water to investigate effects of the cross-linking density on the adhesion and mechanical properties of the hydrogel films in terms of adhesive pull-off force and Hertz-type elastic modulus. As the cross-linker concentration increased, the effective elastic modulus of the hydrogel films increased dramatically at low crosslinking densities and reached a high steady-state value at higher crosslinking densities. The pull-off force decreased with increasing the cross-linker concentration and reached a lower force plateau at high crosslinking densities. An optimal "trade-off" cross-linking density was determined to be 0.02 mole fraction of MBA in the hydrogel, where balanced elastic modulus and adhesive pull-off force can be obtained.
  The Journal of Physical Chemistry B 12/2012; · 3.70 Impact Factor
• Article: Exploitation of Cellular Cytoskeletons and Signaling Pathways for Cell Entry by Kaposi's Sarcoma-Associated Herpesvirus and the Closely Related Rhesus Rhadinovirus.

  Wei Zhang, Shou-Jiang Gao
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  ABSTRACT: As obligate intracellular pathogens, viruses depend on the host cell machinery to complete their life cycle. Kaposi's sarcoma-associated herpesvirus (KSHV) is an oncogenic virus causally linked to the development of Kaposi's sarcoma and several other lymphoproliferative malignancies. KSHV entry into cells is tightly regulated by diverse viral and cellular factors. In particular, KSHV actively engages cellular integrins and ubiquitination pathways for successful infection. Emerging evidence suggests that KSHV hijacks both actin and microtubule cytoskeletons at different phases during entry into cells. Here, we review recent findings on the early events during primary infection of KSHV and its closely related primate homolog rhesus rhadinovirus with highlights on the regulation of cellular cytoskeletons and signaling pathways that are important for this phase of virus life cycle.
  Pathogens. 12/2012; 1(2):102-127.
• Article: Lack of association between parental ABO blood type and autism spectrum disorders.

  Zhao-Tang Wu, Wei Zhang, She-Qing Zhang, Jian-Guang Yu, Hong Lei, Wei-Zhong Wang, Xiao-Hong Liu
  CNS Neuroscience & Therapeutics 05/2012; 18(7):604-5. · 4.44 Impact Factor
• Article: Tailoring of mesenchymal stem cells behavior on plasma-modified polytetrafluoroethylene.

  Huaiyu Wang, Dixon T K Kwok, Ming Xu, Haigang Shi, Zhengwei Wu, Wei Zhang, Paul K Chu
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  ABSTRACT: By altering the surface properties of polytetrafluoroethylene (PTFE) substrates using a special PIII technique, mesenchymal stem cells (MSCs) proliferation and osteogenesis can be promoted in culture without osteogenic supplements. The structures are created intrinsically in the PTFE for no risk of materials delamination. Large-scale features and locally different functions can also be readily produced on the same substrate by this technique.
  Advanced Materials 05/2012; 24(25):3315-24. · 13.88 Impact Factor
• Article: "Contact" of nanoscale stiff films.

  Fut K Yang, Wei Zhang, Yougun Han, Serge Yoffe, Yungchi Cho, Boxin Zhao
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  ABSTRACT: We investigated the contact behaviors of a nanoscopic stiff thin film bonded to a compliant substrate and derived an analytical solution for determining the elastic modulus of thin films. Microscopic contact deformations of the gold and polydopamine thin films (<200 nm) coated on polydimethylsiloxane elastomers were measured by indenting a soft tip and analyzed in the framework of the classical plate theory and Johnson-Kendall-Roberts (JKR) contact mechanics. The analysis of this thin film contact mechanics focused on the bending and stretching resistance of thin films and is fundamentally different from conventional indentation measurements where the focus is on the fracture and compression of the films. The analytical solution of the elastic modulus of nanoscopic thin films was validated experimentally using 50 and 100 nm gold thin films coated on polydimethylsiloxane elastomers. The technical application of this analysis was further demonstrated by measuring the elastic modulus of thin films of polydopamine, a recently discovered biomimetic universal coating material. Furthermore, the method presented here is able to quantify the contact behaviors of nanoscopic thin films, effectively providing fundamental design parameters, the elastic modulus, and the work of adhesion, crucial for transferring them effectively into practical applications.
  Langmuir 05/2012; 28(25):9562-72. · 4.19 Impact Factor
• Article: Genome-scale analysis of DNA methylation in lung adenocarcinoma and integration with mRNA expression.

  Suhaida A Selamat, Brian S Chung, Luc Girard, Wei Zhang, Ying Zhang, Mihaela Campan, Kimberly D Siegmund, Michael N Koss, Jeffrey A Hagen, Wan L Lam, Stephen Lam, Adi F Gazdar, Ite A Laird-Offringa
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  ABSTRACT: Lung cancer is the leading cause of cancer death worldwide, and adenocarcinoma is its most common histological subtype. Clinical and molecular evidence indicates that lung adenocarcinoma is a heterogeneous disease, which has important implications for treatment. Here we performed genome-scale DNA methylation profiling using the Illumina Infinium HumanMethylation27 platform on 59 matched lung adenocarcinoma/non-tumor lung pairs, with genome-scale verification on an independent set of tissues. We identified 766 genes showing altered DNA methylation between tumors and non-tumor lung. By integrating DNA methylation and mRNA expression data, we identified 164 hypermethylated genes showing concurrent down-regulation, and 57 hypomethylated genes showing increased expression. Integrated pathways analysis indicates that these genes are involved in cell differentiation, epithelial to mesenchymal transition, RAS and WNT signaling pathways, and cell cycle regulation, among others. Comparison of DNA methylation profiles between lung adenocarcinomas of current and never-smokers showed modest differences, identifying only LGALS4 as significantly hypermethylated and down-regulated in smokers. LGALS4, encoding a galactoside-binding protein involved in cell-cell and cell-matrix interactions, was recently shown to be a tumor suppressor in colorectal cancer. Unsupervised analysis of the DNA methylation data identified two tumor subgroups, one of which showed increased DNA methylation and was significantly associated with KRAS mutation and to a lesser extent, with smoking. Our analysis lays the groundwork for further molecular studies of lung adenocarcinoma by identifying novel epigenetically deregulated genes potentially involved in lung adenocarcinoma development/progression, and by describing an epigenetic subgroup of lung adenocarcinoma associated with characteristic molecular alterations.
  Genome Research 05/2012; 22(7):1197-211. · 13.61 Impact Factor
• Article: Open reduction and internal fixation better than percutaneous plate osteosynthesis in distal tibial fractures.

  Jian Zou, Zhong-Min Shi, Wei Zhang, Chang-Qing Zhang
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  ABSTRACT: ABSTRACT Minimally invasive percutaneous plate osteosynthesis (MIPPO) was compared with traditional open reduction and internal fixation (ORIF) in treating distal tibial fractures. Patients diagnosed with displaced extraarticular distal tibial fractures during October 2005-June 2007 were randomly assigned to a closed (treated using MIPPO) and an open (treated using ORIF) group. Ninety-four patients with fractures were treated and followed up, of which 42 and 52 patients were enrolled in the open and closed groups, respectively. The 94 fracture cases were classified into three types: Type A, 52 (55.3%); Type B, 24 (25.5%); and Type C, 18 (19.1%). The average follow-up time was 15.6 and 16.2 months for the open and closed groups, respectively. In the open group, 35 fractures healed within six months. Delayed union was observed in three fractures and nonunion in four fractures. Two cases had superficial wound infection after operation. No malunion was observed. In the closed group, 47 fractures healed within six months. Delayed union was observed in four fractures. Locking plate was broken nine months after operation in one case. Malunion was observed in five cases: two rotational and three posterior angular deformities. No statistically significant differences were observed in the healing time of Types A and B between the open and closed groups (p > .05). The healing time of Type C in the open group was longer than that in the closed group (p < .05). The first choice for Type C fractures is MIPPO, whereas that for Type A is open reduction.
  Journal of Investigative Surgery 05/2012; 25(5):326-9. · 1.09 Impact Factor
• Article: Immunosuppression effects of bone marrow mesenchymal stem cells on renal interstitial injury in rats with unilateral ureteral obstruction.

  Ying-Li Liu, Ying-Deng Wang, Feng Zhuang, Shu-Li Xian, Jun-Yan Fang, Wei Su, Wei Zhang
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  ABSTRACT: We investigated the effects of intravenously administered bone marrow mesenchymal stem cells (BMSCs) on renal interstitial inflammation and fibrosis. In unilateral ureteral obstruction (UUO) rats, the CD4(+)CD25(+) regulatory T-cell (Treg) cell, macrophage population and some inflammation related cytokines were tested. In the BMSCs -treated rats, renal exhibited lower renal Masson scores, decreased macrophage infiltration and interferon gamma (IFNγ) expression, and increased forkhead transcription factor (Foxp3) and interleukin-10 (IL-10) expression. No significant differences in the CD4(+)CD25(+) Treg population and renal transforming growth factor-β1 (TGFβ1) expression were observed between BMSCs-treated group and control group (p>0.05). In conclusion, BMSCs infusion leads to an anti-inflammation response in the early stage of UUO which may related to paracine mechanism.
  Cellular Immunology 05/2012; 276(1-2):144-52. · 1.97 Impact Factor
• Source

  Available from: Fengchun Ye

  Article: The ubiquitin/proteasome system mediates entry and endosomal trafficking of Kaposi's sarcoma-associated herpesvirus in endothelial cells.

  Whitney Greene, Wei Zhang, Meilan He, Colleen Witt, Fengchun Ye, Shou-Jiang Gao
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  ABSTRACT: Ubiquitination, a post-translational modification, mediates diverse cellular functions including endocytic transport of molecules. Kaposi's sarcoma-associated herpesvirus (KSHV), an enveloped herpesvirus, enters endothelial cells primarily through clathrin-mediated endocytosis. Whether ubiquitination and proteasome activity regulates KSHV entry and endocytosis remains unknown. We showed that inhibition of proteasome activity reduced KSHV entry into endothelial cells and intracellular trafficking to nuclei, thus preventing KSHV infection of the cells. Three-dimensional (3-D) analyses revealed accumulation of KSHV particles in a cytoplasmic compartment identified as EEA1+ endosomal vesicles upon proteasome inhibition. KSHV particles are colocalized with ubiquitin-binding proteins epsin and eps15. Furthermore, ubiquitination mediates internalization of both KSHV and one of its receptors integrin β1. KSHV particles are colocalized with activated forms of the E3 ligase c-Cbl. Knock-down of c-Cbl or inhibition of its phosphorylation reduced viral entry and intracellular trafficking, resulting in decreased KSHV infectivity. These results demonstrate that ubiquitination mediates internalization of both KSHV and one of its cognate receptors integrin β1, and identify c-Cbl as a potential E3 ligase that facilitates this process.
  PLoS Pathogens 05/2012; 8(5):e1002703. · 9.13 Impact Factor
• Article: Clinical characteristics of hand, foot and mouth disease in Harbin and the prediction of severe cases.

  Hong Zhou, Shu-zhen Guo, Hao Zhou, Yue-feng Zhu, Li-juan Zhang, Wei Zhang
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  ABSTRACT: Hand, foot and mouth disease (HFMD) is an emerging public health problem in China, not only threatening the health of children, but also causing tremendous loss and burden to both families and society. The aim of this study was to characterize the epidemiology and clinical features of HFMD, and to understand the key factors affecting HFMD in the Harbin region to provide scientific evidence for effective prevention and control strategies. Epidemiological and clinical information from 2379 randomly chosen cases of HFMD treated at the Harbin Center for Disease Control and Prevention from May 2008 to November 2011 were analyzed. All cases were separated into common and severe HFMD, with key factors for severe HFMD analyzed using multivariable Logistic regression. Among the 2379 patients, 1798 were common cases and 581 severe cases, 14 of which resulted in death. Most cases were in children younger than 5 years. Morbidity peaked in July and was higher in the surrounding country and cities than in Harbin proper. Medical expenses were significantly higher for severe than for common cases (P < 0.001). The primary clinical symptoms were fever and erythema; laboratory examination showed leucocytosis together with pneumonia, carditis, and abnormal electrocardiogram and electroencephalogram in severe cases. Multivariable Logistic regression analysis showed that the key factors for severe HFMD were age, morbidity location, morbidity area, fever duration, mouth mucosal symptoms, and abnormal serum levels of neutrophils (NEUT), hemoglobin and glucose (P < 0.05). To improve prognosis, reduce medical expense and prevent the development of severe cases, we should improve the epidemiological detection of HFMD to treat patients quickly. We should also closely monitor children with the EV71 virus, who present with continuous fever as well as abnormal laboratory results, from areas highly susceptible to HFMD attacks.
  Chinese medical journal 04/2012; 125(7):1261-5. · 0.86 Impact Factor
• Article: [Study on change characters and correlations of iron, zinc and calcium in milk and blood of mother and infant at different stages].

  Na Li, Qing He, Chunhui Ren, Fengzhi Lin, Haihong Li, Wei Zhang
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  ABSTRACT: To assess the change characters of mineral status in breast milk and blood of lactating mothers and infants at different postpartum stages, and to analyze the clinic significance of these changes in breastfeeding. 50 mother-infant pairs at 6 weeks postpartum and 50 mother-infant pairs at 3 months postpartum were randomly selected, and the concentration of iron, zinc and calcium in milk and blood of mothers and infants were measured according to flame atomic absorption spectrometry. Compared the disparity of these minerals at different stages, and analyze the correlations of the ones among milk, blood of mothers and infants. the level of iron and zinc declined through lactation(Fe 0.102 mg/100 g vs 0.0605 mg/100 g, P < 0.05; Zn 0.257 mg/100 g vs 0.171 mg/100 g, P < 0.05). The level of iron ion in blood of infants declined with increasing age (392.45 mg/L vs 356.80 mg/L, P < 0.05). The level of iron, zinc and calcium ion in maternal blood was not associated with these minerals of milk, and separately positively associated with these minerals in blood of infan (r = 0.591, 0.362 and 0.435, P = 0.000, 0.013 and 0.001). The mammary mineral transport is likely an active process, and not apparently associated with maternal mineral status. The decline of milk iron through lactation may be one of the reasons for high prevalence of breast-fed infants' physiologic anemia. Maternal mineral status during pregnancy may have an influence on the mineral levels of infants in early period.
  Wei sheng yan jiu = Journal of hygiene research 03/2012; 41(2):225-7.
• Article: Osteoblast differentiation and disinfection induced by nitrogen plasma-treated surfaces.

  Wei Zhang, Huaiyu Wang, Ayako Oyane, Hideo Tsurushima, Paul K Chu
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  ABSTRACT: Plasma technology is widely employed to tailor the surface chemistry of polymeric biomaterials. In this work, nitrogen-containing functional groups were generated on a polymer surface by N₂ plasma immersion ion implantation (PIII). We evaluated the abilities of the resulting surface to inhibit bacterial growth and to enhance osteoblast differentiation from the perspective of bone tissue engineering. Our results demonstrate that the N₂ PIII-treated polymer surface exhibits antibacterial properties against Escherichia coli. Moreover, the N₂ PIII-treated polymer surface has the ability to enhance differentiation of osteoblasts. N₂ PIII-treated polymer surface may therefore be useful in bone tissue engineering.
  Bio-medical materials and engineering 01/2011; 21(2):75-82. · 1.23 Impact Factor
• Article: Mechanical and biological characteristics of diamond-like carbon coated poly aryl-ether-ether-ketone.

  Huaiyu Wang, Ming Xu, Wei Zhang, Dixon T K Kwok, Jiang Jiang, Zhengwei Wu, Paul K Chu
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  ABSTRACT: Poly aryl-ether-ether-ketone (PEEK) is an alternative to metal alloys in orthopedic applications. Although the polymer provides many significant advantages such as excellent mechanical properties and non-toxicity, it suffers from insufficient elasticity and biocompatibility. Since the elastic modulus of diamond-like carbon (DLC) is closer to that of cortical bone than PEEK, the DLC/PEEK combination is expected to enhance the stability and surface properties of PEEK in bone replacements. In this work, PEEK is coated with diamond-like carbon (DLC) by plasma immersion ion implantation and deposition (PIII&D) to enhance the surface properties. X-ray photoelectron spectrometry (XPS), Raman spectroscopy, and Fourier transform infrared (FTIR) spectroscopy demonstrate successful deposition of the DLC film on PEEK without an obvious interface due to energetic ion bombardment. Atomic force microscopy (AFM) and contact angle measurements indicate changes in the surface roughness and hydrophilicity, and nanoindentation measurements reveal improved surface hardness on the DLC/PEEK. Cell viability assay, scanning electron microscopy (SEM), and real-time PCR analysis show that osteoblast attachment, proliferation, and differentiation are better on DLC/PEEK than PEEK. DLC/PEEK produced by PIII&D combines the advantages of DLC and PEEK and is more suitable for bone or cartilage replacements.
  Biomaterials 11/2010; 31(32):8181-7. · 7.40 Impact Factor
• Source

  Available from: pku.edu.cn

  Article: Rat calvaria osteoblast behavior and antibacterial properties of O(2) and N(2) plasma-implanted biodegradable poly(butylene succinate).

  Huaiyu Wang, Junhui Ji, Wei Zhang, Wei Wang, Yihe Zhang, Zhengwei Wu, Yumei Zhang, Paul K Chu
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  ABSTRACT: Poly(butylene succinate), a novel biodegradable aliphatic polyester with excellent processability and mechanical properties, was modified by O(2) or N(2) plasma immersion ion implantation (PIII). X-ray photoelectron spectroscopy and contact angle measurements were carried out to reveal the surface characteristics of the treated and control specimens. The in vitro effects of the materials on seeded osteoblasts were detected by cell viability assay, alkaline phosphatase activity test, and real-time polymerase chain reaction analysis. Plate counting was performed to investigate the antibacterial properties. Our results show that both PIII treatments significantly improve the hydrophilicity of PBSu, and CO and nitrogen groups (CNH and CNH(2)) can be detected on the PBSu after O(2) and N(2) PIII, respectively. The modified samples exhibit similar compatibility to osteoblasts, which is better than that of the control, but O(2) PIII and N(2) PIII produce different effects according to the osteogenic gene expressions of seeded osteoblasts on the materials. Moreover, the N(2) plasma-modified PBSu exhibits anti-infection effects against Staphylococcus aureus and Escherichia coli but no such effects can be achieved after O(2) PIII.
  Acta biomaterialia 08/2009; 6(1):154-9. · 3.98 Impact Factor
• Article: Biocompatibility and bioactivity of plasma-treated biodegradable poly(butylene succinate).

  Huaiyu Wang, Junhui Ji, Wei Zhang, Yihe Zhang, Jiang Jiang, Zhengwei Wu, Shihao Pu, Paul K Chu
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  ABSTRACT: Poly(butylene succinate) (PBSu), a novel biodegradable aliphatic polyester with excellent processability and mechanical properties, is a promising substance for bone and cartilage repair. However, it typically suffers from insufficient biocompatibility and bioactivity after implantation into the human body. In this work, H(2)O or NH(3) plasma immersion ion implantation (PIII) is conducted for the first time to modify the PBSu surface. Both the treated and control specimens are characterized by X-ray photoelectron spectroscopy, contact angle measurements and atomic force microscopy. The plasma treatments improve the hydrophilicity and roughness of PBSu significantly and the different PIII processes result in similar hydrophilicity and topography. C-OH and C-NH(2) functional groups emerge on the PBSu surface after H(2)O and NH(3) PIII, respectively. The biological results demonstrate that both osteoblast compatibility and apatite formability are enhanced after H(2)O and NH(3) PIII. Furthermore, our results suggest that H(2)O PIII is more effective in rendering PBSu suitable for bone-replacement implants compared to NH(3) PIII.
  Acta biomaterialia 08/2008; 5(1):279-87. · 3.98 Impact Factor
• Article: Ag and Ag/N2 plasma modification of polyethylene for the enhancement of antibacterial properties and cell growth/proliferation.

  Wei Zhang, Yunjun Luo, Huaiyu Wang, Jiang Jiang, Shihao Pu, Paul K Chu
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  ABSTRACT: Polyethylene (PE) is one of the most common materials used for medical implants. However, it usually possesses low biocompatibility and insufficient antibacterial properties. In the work described here, plasma immersion ion implantation (PIII) is employed to implant silver into PE to enhance both its antibacterial properties and its biocompatibility. Our results show that Ag PIII can give rise to excellent antibacterial properties and induces the formation of functional groups such as C-O and C=C. These C-O and C=C groups on the modified surface can trigger the growth of the human fetal osteoblastic cell line (hFOB). Furthermore, combining N(2) and Ag PIII prolongs the antibacterial effects, but nitrogen-containing functional groups such as C-N and C=N created by N(2) co-PIII negatively impact proliferation of hFOB on the surface. According to our experimental investigation on cell proliferation, functional groups such as C-N and C=N created by nitrogen PIII are disadvantageous to cell growth whereas the C-O and C=C groups benefit cell growth. Both the antibacterial activity and biocompatibility of PE can be enhanced by means of the proper plasma surface treatment.
  Acta biomaterialia 07/2008; 4(6):2028-36. · 3.98 Impact Factor
• Article: Thermal Decomposition of Aminonitrobenzodifuroxan

  Wei Zhang, Yunjun Luo, Jie Li, Xiaomeng Li
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  ABSTRACT: In this study, the thermal decomposition properties of aminonitrobenzodifuroxan are studied using a differential scanning calorimeter (DSC), a thermogravimeter (TG), an X-ray diffractometer, a mass spectrometer (MS), and a Fourier transform infrared spectrometer (FTIR). The results demonstrate that aminonitrobenzodifuroxan undergoes thermal decomposition in the solid state. Under elevated temperatures, the decomposition primarily involves two steps: separation of nitro group and ring-scission of the furoxan circles at 198.1 °C, and decomposition of the relatively stable residues (benzofuroxan circle) at 199.1 °C. Moreover, it is found that among the products, nitrogen dioxide undergoes oxidation and catalysis on the host molecule during the whole decomposition. Based on Kissinger and Ozawa functions, we deduce that the activation energies of these two reactions are 167.68 and 204.55 kJ mol−1, respectively. The released energy (ΔH) of CL-18 is −1781.8 J g−1.
  Propellants Explosives Pyrotechnics 06/2008; 33(3):177 - 181. · 1.10 Impact Factor