ObjectiveModifications to implant surface properties, including topography, chemistry, and wettability, alter immune response, osteoblast differentiation of bone marrow stromal cells (MSCs), and implant integration in vivo. Dielectric barrier discharge (DBD) plasma treatment has been used to sterilize surfaces and remove adsorbed carbon, improving wettability. However, unless it is used immediately prior to placement, ambient atmospheric hydrocarbons rapidly adhere to the surface, thereby reducing its hydrophilicity. Moreover, this method is not practical in many clinical settings. The aim of this study was to evaluate the effectiveness of an on-site benchtop modification technique for implants at time of placement, consisting of a DBD plasma that is used to sterilize implants that are pre-packaged in a vacuum. Effects of the plasma-treatment on implant surface properties and cellular response of MSCs and osteoblasts were assessed in vitro.MethodsTitanium-aluminum-vanadium implant surfaces were grit-blasted (GB) or grit-blasted and acid-etched (AE), and packaged under vacuum. AE surfaces were also plasma-treated using the benchtop device (GB + AE) and then removed from the vacuum. GB surface morphology was altered with AE but AE microroughness was not changed with the plasma-treatment. Plasma-treatment increased the surface wettability, but did not alter surface atomic concentrations of titanium, oxygen, or carbon.ResultsMSCs and osteoblast-like cells (MG63 s) produced increased concentrations of osteocalcin, osteopontin, and osteoprotegerin after plasma-treatment of AE surfaces compared to non-plasma-treated AE surfaces; production of IL6 was reduced and IL10 was. Aging GB + AE surfaces for 7 days after plasma-treatment but still in the vacuum environment reduced the effectiveness of plasma on cellular response.SignificanceOverall, these data suggest that application of benchtop plasma at the time of implant placement can alter the surface free energy of an implant surface without modifying surface chemical composition and enhance the differentiation and activity of MSCs and osteoblasts that are in contact with these implant surfaces. 相似文献
Surface-textured calcium phosphate coatings at four different length scales were synthesized on titanium-based alloys using a pulsed Nd:YAG laser system by a direct melting technique. The textures were obtained by varying the laser spot overlap with a change in laser traverse speed. Surface roughness measurements of the textured coatings carried out using a white light interferometer indicated a decrease in roughness with increasing laser scan speed. Wettability of the coated samples measured using a static sessile drop technique demonstrated an increased hydrophilicity with increasing laser scan speed. The influence of such textures and the associated surface roughness on the precipitation kinetics of hydroxyapatite (HA) during immersion in simulated body fluid (SBF) was the prime focus of the present paper. The mineralized samples obtained after immersion in SBF were characterized using X-ray diffraction, energy-dispersive spectroscopy and scanning electron microscopy to understand the kinetics of HA precipitation. The results thereafter confirmed that the precipitation kinetics of HA was strongly modulated by the varying surface roughness. 相似文献
The purpose of this study was to investigate the viscosity and wettability of a water-soluble extract of yam and its effects on lysozyme and peroxidase activities.
Design
Human whole saliva, yam tuber, hen egg-white lysozyme, and bovine lactoperoxidase were used. Viscosity was measured with a cone-and-plate digital viscometer, while wettability was determined by measuring the contact angle. Lysozyme activity was determined by the turbidimetric method. Peroxidase activity was determined using the NbsSCN assay. Hydroxyapatite beads were used as a solid-phase.
Results
The viscosity of the yam solution was proportional to its concentration, with diluted yam solutions at 1:5 and 1:10 in simulated salivary buffer displaying similar viscosity values to unstimulated whole saliva and stimulated whole saliva, respectively. The contact angle of yam solution was not significantly different according to the tested materials or yam concentrations. Contact angles of yam solutions on acrylic resin were higher than those of human saliva. Yam affected lysozyme and peroxidase activities, and those effects were different on the hydroxyapatite surface versus in solution. Hydroxyapatite-adsorbed yam increased subsequent adsorption of lysozyme and peroxidase.
Conclusion
We objectively confirmed the similarity of the viscoelastic properties of yam and human saliva, suggesting a role for yam in the development of effective saliva substitutes. 相似文献
A novel low-pressure radio-frequency plasma treatment protocol was developed to achieve the effective through-thickness surface modification of large porous poly (d,l-lactide) (PDLLA) polymer scaffolds using air or water: ammonia plasma treatments. Polymer films were modified as controls. Scanning electron micrographs and maximum bubble point measurements demonstrated that the PDLLA foams have the high porosity, void fraction and interconnected pores required for use as tissue engineering scaffolds. The polymer surface of the virgin polymer does contain acidic functional groups but is hydrophobic.
Following exposure to air or water: ammonia plasma, an increased number of polar functional groups and improved wetting behaviour, i.e. hydrophilicity, of wet surfaces was detected. The number of polar surface functional groups increased (hence the decrease in water contact angles) with increasing exposure time to plasma. The change in surface composition and wettablility of wet polymer constructs was characterised by zeta potential and contact angle measurements. The hydrophobic recovery of the treated PDLLA polymer surfaces was also studied. Storage of the treated polymer constructs in ambient air caused an appreciable hydrophobic recovery, whereas in water only partial hydrophobic recovery occurred. However, in both cases the initial surface characteristics decay as function of time. 相似文献
This multicenter study has revealed that treating a woven polyethylene terephthalate (polyester) ligament with a radiofrequency
(RF)-generated glow discharge (RFGD) produces marked benefits in terms of increased cell attachment and proliferation on the
implant surface. In vitro tests of the same material revealed that the number of synovial fibroblasts attached to the treated
samples after 14 days was four times that of the untreated material. Many of the cells were spread over the surface of a single
filament, and some formed bridges between one filament and the next. The incorporation of [3H]-thymidine by synovial stromal cells (a measure of the amount of cell division) growing on the treated material was five
times that on the untreated samples. The amount of DNA present on the treated material was also found to be almost an order
of magnitude greater than that on untreated samples. This increase in cell attachment and proliferation is almost certainly
related to a notable increase in wettability of the polyester surface induced by treatment. Mechanical tests revealed that,
for ligaments with a nominal ultimate tensile strength of 2100 N, RF-generated glow treatment reduced the ligament's strength
by 12% but increased its stiffness by 15%. After a medium-term fatigue test (10.8 million cycles), however, there appeared
to be recovery of the mechanical properties, with the strength and stiffness of untreated and treated samples being essentially
the same. After exhaustive fatigue tests (more than 62 million cycles) the residual strength of the treated ligaments was
only 9% lower than that of the unfatigued and untreated ligaments.
Received: July 1, 2002 / Accepted: October 22, 2002
Acknowledgments. The authors thank Xiros plc for providing ligament samples. We also thank the following individuals for their contribution
to the work described in this study: Mr. Les Johnson, School of Textile Industries, University of Leeds, for carrying out
wettability tests; Dr. David Woolley, Department of Medicine, University of Manchester for supplying cells for the study at
Yorkshire Regional Tissue Bank; Mr. John Tresnan, Xiros plc, for carrying out the mechanical tests. We especially acknowledge
the contribution of Sangjin Kang to the work carried out at the School of Biochemistry and Molecular Biology, University of
Leeds.
Offprint requests to: J.R.J. Rowland 相似文献
Poor wettability of denture relining materials may lead to retention problems and patient discomfort.
PURPOSE
Purpose of this study is to compare and evaluate wettability of nine denture relining materials using contact angle measurements under air and water storage over time.
MATERIAL AND METHODS
Nine denture relining materials were investigated in this study. Two heat-curing polymethyl-methacrylate (PMMA) denture base materials: Vertex RS, Lang, one self-curing polyethyl-methacrylate (PEMA) chairside reline resin: Rebase II, six silicone relining materials: Mucopren soft, Mucosoft, Mollosil® plus, Sofreliner Touch, GC Reline™ Ultrasoft, Silagum automix comfort were used in this experiment. Contact angles were measured using high-resolution drop shape analysis system (DSA 10-MK2, KRUESS, Germany) under three conditions (in air after setting, 1 hour water storage, and 24 hours water storage). Nine materials were classified into three groups according to material composition (Group 1: PMMA, Group 2: PEMA, Group 3: Silicone). Mean values of contact angles were compared using independent samples t-test and one-way ANOVA, followed by a Scheffe''s post hoc analysis (α= 0.01).
RESULTS
Contact angles of materials tested after air and water storage increased in the following order: Group 1 (PMMA), Group 2 (PEMA), Group 3 (Silicone). Heat-cured acrylic denture base resins had more wettability than silicone relining materials. Lang had the highest wettability after 24 hours of water storage. Silicone relining materials had lower wettability due to their hydrophobicity. Wettability of all denture relining materials, except Rebase II and Mollosil® plus, increased after 24 hours of water storage.
CONCLUSIONS
Conventional heat-cured resin showed the highest wettability, therefore, it can be suggested that heat-cured acrylic resin is material of choice for denture relining materials. 相似文献
To evaluate the surface and wettability characteristics and the microbial biofilm interaction of graphene coating on titanium.
Methods
Graphene was deposited on titanium (Control) via a liquid-free technique. The transfer was performed once (TiGS), repeated two (TiGD) and five times (TiGV) and characterized by AFM (n = 10), Raman spectroscopy (n = 10), contact angle and SFE (n = 5). Biofilm formation (n = 3) to Streptococcus mutans, Enterococcus faecalis, Pseudomonas aeruginosa and Candida albicans was evaluated after 24 h by CV assay, CFU, XTT and confocal microscopy. Statistics were performed by one-way Anova, Tukey’s tests and Pearson’s correlation analysis at a pre-set significance level of 5 %.
Results
Raman mappings revealed coverage yield of 82 % for TiGS and ≥99 % for TiGD and TiGV. Both TiGD and TiGV presented FWHM > 44 cm?1 and ID/IG ratio < 0.12, indicating multiple graphene layers and occlusion of defects. The contact angle was significantly higher for TiGD and TiGV (110° and 117°) comparing to the Control (70°). The SFE was lower for TiGD (13.8 mN/m) and TiGV (12.1 mN/m) comparing to Control (38.3 mN/m). TiGD was selected for biofilm assays and exhibited significant reduction in biofilm formation for all microorganisms compared to Control. There were statistical correlations between the high contact angle and low SFE of TiGD and decreased biofilm formation.
Significance
TiGD presented high quality and coverage and decreased biofilm formation for all species. The increased hydrophobicity of graphene films was correlated with the decreased biofilm formation for various species. 相似文献
ObjectiveThe objective of this study was to determine the effect of two plasma surface treatments on the biologic responses of PEEK medical implants manufactured by fused filament fabrication (FFF) 3D printing technology.MethodsThis study created standard PEEK samples using an FFF 3D printer. After fabrication, half of the samples were polished to simulate a smooth PEEK surface. Then, argon (Ar) or oxygen (O2) plasma was used to modify the bioactivity of FFF 3D printed and polished PEEK samples. Scanning electron microscopy (SEM) and a profilometer were used to determine the microstructure and roughness of the sample surfaces. The wettability of the sample surface was assessed using a drop shape analyzer (DSA) after plasma treatment and at various time points following storage in a closed environment. Cell adhesion, metabolic activity, proliferation, and osteogenic differentiation of SAOS-2 osteoblasts were evaluated to determine the in vitro osteogenic activity.ResultsSEM analysis revealed that several spherical nanoscale particles and humps appeared on sample surfaces following plasma treatment. The wettability measurement demonstrated that plasma surface treatment significantly increased the surface hydrophilicity of PEEK samples, with only a slight aging effect found after 21 days. Cell adhesion, spreading, proliferation, and differentiation of SAOS-2 osteoblasts were also up-regulated after plasma treatment. Additionally, PEEK samples treated with O2 plasma demonstrated a higher degree of bioactivation than those treated with Ar.SignificancePlasma-modified PEEK based on FFF 3D printing technology was a feasible and prospective bone grafting material for bone/dental implants. 相似文献