Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Wettability”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 397 records · Page 22Linked to original sources

Interaction of fibroblasts on polycarbonate membrane surfaces with different micropore sizes and hydrophilicity.

Surface topography appears to be an important but often neglected factor in implant performance. In this study, fibroblasts were cultured on a range of porous polycarbonate (PC) membranes with well defined surface topography (track-etched micropores, 0.2-8.0 microm in diameter) and wettability gradients. The wettability gradient on the PC membrane surfaces was produced by treating the surfaces with corona from a knife-type electrode whose power increased gradually along the sample length. The PC membrane surfaces were characterized by scanning electron microscopy (SEM) and the water contact angle measurement. Fibroblasts were cultured on the corona-treated PC membrane surfaces with different micropore sizes for 1 and 2 days. The cells attached on the membrane surfaces were examined by SEM and the cell density on the surfaces was estimated by counting the number of attached cells along the wettability gradient. It was observed that the cells were adhered and grew more on the hydrophilic positions of the membrane surfaces than the more hydrophobic ones, regardless of micropore size. It was also observed that cell adhesion and growth decreased gradually with increasing micropore size of the membrane surfaces. It seems that the cell adhesion and growth were progressively inhibited as the membrane surfaces had micropores with increasing size, probably due to surface discontinuities produced by tract-etched pores. On the membrane surfaces with smaller micropore sizes, the cells seemed to override these surface discontinuities.

3T3 Cells↗

Albumin and fibronectin protein adsorption on CO2-laser-modified biograde stainless steel.

The surface properties of a biomaterial play an essential role in protein adsorption, which in turn determines the cellular response to the adsorbed surface. In order to obtain a surface that would yield favourable protein adsorption for successful cellular response, the surface properties of a biograde stainless steel were modified by CO2 laser treatment. An investigation of the CO2-laser-modified surface properties and the effects thereof on the adsorption of human serum albumin (no-cell adhesive) and human plasma fibronectin (cell adhesive) was conducted. It was found that the thickness of the adsorbed fibronectin layer increased with increasing CO2 laser power density, while the thickness of the adsorbed albumin layer decreased with increasing CO2 laser power density. The surface roughness and wettability characteristics contributed to the observed changes in protein adsorption. The wettability characteristics of the biograde stainless steel were found to be the predominant mechanism governing the observed change in protein adsorption. Since the wettability characteristics of the biograde stainless steel can be modified in an efficient and controllable way with the CO2 laser, it is believed that this work presents a demonstrable alternative to the techniques currently available for enhancing the biocompatibility of biograde stainless steels.

Adsorption↗

New method for evaluation of hard contact lens materials with regard to cell injury by dynamic contact.

To establish a new method for evaluation of contact lens materials, we studied the porcine endothelial cell injury caused by dynamic contact (rotatory rubbing) with three kinds of hard contact lenses (HCL). The HCLs used were 1) PMMA HCL, 2) oxygen-permeable HCL composed of a graft copolymer of dextran derivative and methylmethacrylate (MMA) (Suncon Mild II, 12 Dk), and 3) oxygen-permeable-HCL composed of a copolymer of a monomer containing silicone, a monomer containing fluorine, and MMA (RGPL-A, 216 Dk). Cell injury rates were significantly different among these HCLs (Suncon Mild II < PMMA < RGPL-A) although there were no differences in rotatory rubbing forces. The smoothness of HCL surface, the qualities of injured cell layers observed by scanning electron microscopy, and the water wettability of HCLs were not correlated with cell injury rate. These results suggest that physicochemical properties of materials other than rotatory rubbing force, smoothness, and water wettability were involved in the cell injury. Our evaluation method for biomaterials that injure the corneal endothelial cells by dynamic contact should be very useful for the development of biomaterials or medical devices, including HCLs and intracardiac and urethral catheters.

Animals↗

Effect of parallel surface microgrooves and surface energy on cell growth.

To evaluate the effect of surface treatment and surface microtexture on cellular behavior, smooth and microtextured silicone substrata were produced. The microtextured substrata possessed parallel surface grooves with a width and spacing of 2.0 (SilD02), 5.0 (SilD05), and 10 microns (SilD10). The groove depth was approximately 0.5 microns. Subsequently, these substrata were either left untreated (NT) or treated by ultraviolet irradiation (UV), radiofrequency glow discharge treatment (RFGD), or both (UVRFGD). After characterization of the substrata, rat dermal fibroblasts (RDF) were cultured on the UV, RFGD, and UVRFGD treated surfaces for 1, 3, 5, and 7 days. Comparison between the NT and UV substrata revealed that UV treatment did not influence the contact angles and surface energies of surfaces with a similar surface topography. However, the contact angles of the RFGD and UVRFGD substrata were significantly smaller than those of the UV and NT substrata. The dimension of the surface microevents did not influence the wettability characteristics. Cell culture experiments revealed that RDF cell growth on UV-treated surfaces was lower than on the RFGD and UVRFGD substrata. SEM examination demonstrated that the parallel surface grooves on the SilD02 and SilD05 substrata were able to induce stronger cell orientation and alignment than the events on SilD10 surfaces. By combining all of our findings, the most important conclusion was that physicochemical parameters such as wettability and surface free energy influence cell growth but play no measurable role in the shape and orientation of cells on microtextured surfaces.

Animals↗

The lipopeptides mycosubtilin and surfactin enhance spreading of Bacillus subtilis strains by their surface-active properties.

The colonizing behaviour and the pellicle formation of Bacillus subtilis strains producing different families of lipopeptides were evaluated under several cultural conditions. The pattern of lipopeptides produced determined the architecture of the colony on a swarming medium as well as the flotation and the thickness of the pellicle formed at the air/liquid interface. The overproduction of mycosubtilin, a lipopeptide of the iturin family, led to increased spreading but had no effect on pellicle formation. A physico-chemical approach was developed to gain an insight into the mode of action of the biosurfactants facilitating the colonization. A relationship between surface tension of the culture medium and spreading of a lipopeptide non-producing strain, B. subtilis 168, was established. Goniometry was used to highlight the modification of the in situ wettability in the area where spreading was enhanced. On a solid medium, co-cultures of a surfactin producing with other strains showed a diffusion ring of the surfactin around the colony. This ring characterized by a higher wettability favoured the propagation of other colonies.

Bacillus subtilis↗

Cytocompatibility of novel tin oxide thin films.

The capacity of tin oxide films to support cell growth was investigated. Three substrates were used for the test: glass coverslips, glass coverslips spin coated with tin oxide and commercially available 316 stainless steel. The wettabilities and surface roughness of the three surfaces were measured before seeding 3T3 fibroblasts onto the samples. The behaviour of the cells grown on the tin oxide was compared to the uncoated glass and the steel and results showed that the cell growth on tin oxide compared favourably with the other substrates. The surface wettability appeared to have the strongest effect on cell adhesion to tin oxide.

3T3 Cells↗

Importance of integrin beta1-mediated cell adhesion on biodegradable polymers under serum depletion in mesenchymal stem cells and chondrocytes.

To evaluate the predominant mechanism of chondrogenic cell [mesenchymal stem cells (MSCs) and chondrocytes] adhesion under serum free conditions, we measured the surface roughness and wettability of poly(lactic acid:polyglycolic acid=75:25) (PLGA), poly(lactic acid) (PLA), and poly(-epsilon-caprolactone) (PCL)-coated glass plates. Also to evaluate the biological reactions involved in cell-polymer interactions, integrin beta1, one of the cell adhesion molecules, was blocked with monoclonal antibody. In cell attachment test, MSCs and chondrocytes adhesion to synthetic polymers in 1h were very low and ranged from 2.8% to 8.0%. In present study, the correlation between attachment rate and surface roughness, contact angle, or integrin beta1 blocking on PLGA, PLA and PCL-coated plates could not be proved. However, we found that L-arginine-coated PLA highly increased the attachment rates of MSCs (30.2%) and of chondrocytes (26%), whereas integrin beta1 blocking significantly decreased these attachment rates to 5.6% and 7.4%, respectively, suggesting that increased cell adhesion to L-arginine-coated plates is mediated by integrin beta1. In this study, we showed that polymer characteristics such as roughness and wettability did not play an important role in cell adhesion under serum free conditions, because there was no significant difference according to polymer characteristics, whereas biological interactions mediated by integrin beta1 were critical during the early period of cell adhesion. The results suggest that L-arginine could be useful for facilitating early cell adhesion to synthetic polymers in cartilage tissue engineering.

Absorbable Implants↗

Stability of plasma-treated silicone rubber and its influence on the interfacial aspects of blood compatibility.

Medical-grade polydimethylsiloxane elastomer was subjected to low-powered plasma treatment in the presence of four different gases: O(2), Ar, N(2) and NH(3). Changes to the surface chemistry immediately after processing and the stability of the treatments following ageing in phosphate buffered saline or air for up to 1 month were investigated using X-ray photoelectron spectroscopy and dynamic contact angle analysis. Changes in surface morphology were assessed using optical microscopy and atomic force microscopy. All treatments resulted in an increase in wettability, attributed to major changes in chemistry combined with modest etching. Furthermore, the primary site of attack of the plasma species appeared to be dependent upon the feed gas implemented. The two main chemical changes observed after ageing were due to reactions with the storage media and relaxation processes resulting in further changes in wettability. The influence of the surface modifications on the blood compatibility of the materials was investigated by assessing contact phase activation using a partial thromboplastin time assay. It was demonstrated that the O(2) and Ar plasma treatments reduced the performance of the silicone but the N(2) and NH(3) treatments had a significantly beneficial effect on the activation of the coagulation cascade.

Biocompatible Materials↗

BHK cells behaviour on laser treated polydimethylsiloxane surface.

The surface of polydimethylsiloxane (PDMS) was modified using a CO2-pulsed laser to evaluate the changes in physical and biological properties of the treated surface. Attachment of anchorage dependent cells, namely baby hamster kidney (BHK) fibroblastic cells, on PDMS surface was investigated in stationary culture conditions. BHK cell adhesion and growth on the PDMS surfaces were studied using scanning electron microscopy (SEM) and optical microscopy. To evaluate the surface wettability, water drop contact angles were determined. The laser treated PDMS surfaces showed high hydrophobicity and low cell adhesion, no spreading and growth in comparison with the unmodified PDMS. It was found that both the wettability and surface structure of the PDMS surface control cell attachment and growth.

Animals↗

Surface modification of poly(ethylene terephthalate) via hydrolysis and layer-by-layer assembly of chitosan and chondroitin sulfate to construct cytocompatible layer for human endothelial cells.

Surface modification of poly(ethylene terephthalate) (PET) film was performed by surface hydrolysis and layer-by-layer (LBL) assembly followed a mechanism of electrostatic adsorption of oppositely charged polymers, exemplified with chitosan and chondroitin sulfate (CS). Hydrolysis of PET in concentrated alkaline solution produced a carboxyl-enriched surface. The changes of weight loss and surface chemistry, morphology and wettability were monitored and verified by UV-vis spectroscopy, atomic force microscopy (AFM) and water contact angle. Assembly of positively charged chitosan and negatively charged CS was then conducted in a LBL manner to create multilayers on the hydrolyzed PET film. The process of layer growth and oscillation of surface wettability were monitored by UV-vis spectroscopy and water contact angle measurement, respectively. In vitro cell culture revealed that the adherence of endothelial cells was significantly enhanced on the biomacromolecules-modified PET film with preserved endothelial cell function, in particular on those assembled with larger number of chitosan/CS layers. However, with regard to cell proliferation and viability properties after cultured for 4 days, minor difference was determined between the modified and the unmodified PET films.

Adsorption↗

Effect of surface charge and hydrophobicity of polyurethanes and silicone rubbers on L929 cells response.

Wettability and zeta potential studies were performed to characterize the hydrophobicity and surface charge of virgin and oxygen plasma irradiated silicone rubbers and polyurethane (polyether and polyesther) samples and evaluate the effect of hydrophobicity and surface charge on fibroblast cells attachment and growth. The surface properties of polyurethanes and silicones and plasma irradiated surfaces were compared by water drop contact angle and zeta potential measurement. Using SEM photomicrographs to study the morphology of virgin and plasma irradiated samples surfaces and light microscopy for study the behavior of cell attachment on these surfaces. Water drop contact angle measurements show that in despite of the silicones, the polyurethanes become more hydrophobic and have stable surface than silicones. Results show that wettability of plasma treated silicones increase and after 48 h recovery take place. Zeta potential measurements noticed that plasma treated polyetherurethane surface is more negatively charge, and consequently attachment of the L929 fibroblast cells decreased whereas on silicones surfaces, negatively charge surfaces show increase cells attachment.

Animals↗

Hydrophilicity of elastomeric non-aqueous impression materials during setting.

OBJECTIVES: Clinically relevant accuracy of dental impressions depends on flowing and wetting properties of the applied impression materials. The major objective of this study was to develop an experimental set-up and an analysis strategy for wettability measurements of impression materials during their working time. METHODS: High-resolution drop shape analysis was used to study contact angles on thin unset films of two polyether and two vinyl polysiloxane (VPS) impression materials. Qualitative and quantitative analysis of the contact angle evolution in terms of initial values and the equilibrium state of hydrophilicity, as well as in terms of kinetics of hydrophilization were extended using a mathematical model approach. RESULTS: Compared to VPS impression materials, polyethers show pronounced and constant initial hydrophilicity throughout prescribed working time. The kinetics of the VPS impression materials towards more hydrophilic equilibrium surface states is very fast compared to polyethers. This possibly balances the disadvantage of the initial VPS impression materials hydrophobicity. Generally, the experimental and analytical methods have proven to yield detailed insights into the wetting characteristics during setting. SIGNIFICANCE: Both, high initial and a fast kinetics towards increased hydrophilicity may improve flowing and wetting processes during impression taking. Therefore, time-resolved wettability studies should be regarded when developing advanced impression materials and defining working times. They may supplement rheological studies.

Chemical Phenomena↗

Bond strength of resin cements to H2O2-treated titanium plates.

OBJECTIVE: This study investigated the effects of H(2)O(2)-treatment of titanium surfaces on cement shear bond strengths, and characterized H(2)O(2)-treated titanium surfaces. METHODS: Using 34.5% hydrogen peroxide solution, cp Ti plates (10 mm x 10 mm x 1 mm) were treated by (1) an immersion method, and (2) halogen irradiation while immersed in H(2)O(2) for varying times. A cylindrical block (6 mm diameter, 4 mm height) of four different cements was bonded onto H(2)O(2)-treated surfaces. The cement bond strengths were evaluated under shear mode. Treated surfaces were also characterized for color change, wettability, AC impedance, and transmission electron diffraction of stripped oxide film. RESULTS: The cement shear bond strength of cp Ti treated with H(2)O(2) and halogen for 160 s was the highest and was approximately 14 times higher than the un-treated control cp Ti plates. Bond strengths are correlated linearly to wettability. The more surface wetted with the cement material, the higher the resultant shear bond strength value. SIGNIFICANCE: These results suggest that a combined treatment of hydrogen peroxide and halogen light irradiation provides an effective surface condition with appropriate oxide film thickness to enhance the cement bond strength.

Color↗

Long-term evaluation of the needle surface wax condition of Pinus sylvestris around different industries in Lithuania.

The aim of our study was to evaluate the annual dynamics of needle surface wax erosion and wettability in Scots pines exposed to a gradient of industrial pollutants emitted from the main factories of Lithuania: a nitrogen fertilizer factory, an oil refinery and a cement factory. Decreased emissions (in the case of the oil refinery and the cement factory) were reflected in the increased structural surface area (SSA, i.e. area covered by tubular waxes) on the needles. The nearly constant amount of emissions from the nitrogen fertilizer factory within the 1994-2000 period corresponded to negligible annual differences in SSA. Annual changes in the hydrophobicity of needles on the investigated transects were small. Despite the decreased pollution within the 7-year period, industrial emissions are still causing significantly accelerated wax erosion and increased wettability in needles sampled from the stands most heavily affected by pollutants.

Ecology↗

Secondary imbibition in NAPL-invaded mixed-wet sediments.

A previously developed pore network model is used here to study the spontaneous and forced secondary imbibition of a NAPL-invaded sediment, as in the displacement of NAPL by waterflooding a mixed-wet soil. We use a 3D disordered pore network with a realistic representation of pore geometry and connectivity, and a quasi-static displacement model that fully describes the pore-scale physics. After primary drainage (NAPL displacing water) up to a maximum capillary pressure, we simulate secondary imbibition (water displacing NAPL). We conduct a parametric study of imbibition by varying systematically the controlling parameters: the advancing contact angles, the fraction of NAPL-wet pores, the interfacial tension, and the initial water saturation. Once the secondary imbibition is completed, the controlling displacement mechanisms, capillary pressures, relative permeabilities, and trapped NAPL saturations are reported. It is assumed that NAPL migrates into an initially strongly water-wet sediment, i.e., the receding contact angles are very small. However, depending on the surface mineralogy and chemical compositions of the immiscible fluid phases, the wettability of pore interiors is altered while the neighborhoods of pore corners remain strongly water-wet-resulting in a mixed-wet sediment. Here, we compare three different levels of wettability alteration: water-wet (advancing contact angles (20 degrees to 55 degrees), intermediate-wet (55 degrees to 120 degrees), and NAPL-wet (120 degrees to 155 degrees). The range of advancing contact angles and the fraction of NAPL-wet pores have dramatic effects on the NAPL-water capillary pressures and relative permeabilities. The spatially inhomogeneous interfacial tension has a minor impact on the trapped NAPL saturation and relative permeability to NAPL, and a slight effect on the relative permeability to water. The initial water saturation has a slight effect on the two-phase flow characteristics of water-wet sediments; however, with more NAPL-wet pores in the sediment, it starts to have a profound effect on the water and NAPL relative permeabilities.

Environmental Monitoring↗

Effect of the dentin cleansing techniques on dentin wetting and on the bond strength of a resin luting agent.

STATEMENT OF PROBLEM: Remnants of the provisional cement on prepared teeth may have an adverse effect on the performance of the definitive luting agent. PURPOSE: This in vitro study investigated the effect of different dentin cleansing techniques on the bond strength of a resin luting agent and dentin wetting. MATERIAL AND METHODS: Sixty buccal or lingual coronal portions of human molar teeth were mounted, with the buccal or lingual surfaces up, in acrylic resin blocks. The specimens were prepared until the dentin was exposed and a eugenol-containing provisional cement (Temp Bond) was applied to the dentin surfaces. After mechanical removal of the cement with a carving instrument, specimens were divided into 6 groups of 10 specimens each. The dentin surfaces of the specimens were treated with 1 of 5 cleansing techniques: Group S, cleansing agent (Sikko Tim); Group C, cleansing agent (Cavity Cleanser); Group O, rotary instrumentation (OptiClean); Group OS, rotary instrument preceding Sikko Tim; and Group OC, rotary instrumentation preceding Cavity Cleanser. The remaning 10 specimens were untreated and served as controls (CT). An adhesive resin luting agent (Variolink II) was applied to all specimens. Shear bond strength (MPa) was measured using a universal testing machine at a 0.5 mm/min crosshead speed. To measure the contact angle, another 6 groups (n=5) were prepared using the same methods. Contact angle measurements were performed to assess wettability using the Axisymmetric Drop Shape Analysis-Contact Diameter (ADSA-CD) technique. Wettability measurements were made with water. Data were statistically analyzed by 1-way analysis of variance with Tukey HSD tests (alpha=.05). The effect of the dentin cleansing techniques on removing the provisional cement from the dentin surface was examined with scanning electron microscope (SEM). RESULTS: Specimens cleaned with all techniques showed stronger shear bond strength values than control specimens (P<.001), with the exception of C specimens. The surface cleansing techniques tested affected the dentin wetting significantly in comparison with the control group (P<.001), except for the C and the O groups. There was no significant difference in wetting between the groups C and O. The SEM observations demonstrated that the dentin cleansing techniques left differing amounts of provisional cement remnants. CONCLUSION: Specimens treated with only the cleansing agent Sikko Tim showed the highest bond strength, likely due to the solvent effect of Sikko Tim on the removal of provisional cement. The lowest bond strength was obtained with the rotary instrument. It was concluded that the provisional cement could plug the dentinal tubules into which the resin luting agent penetrates.

Dental Bonding↗

Relationship between sandblasting and composite resin-alloy bond strength by a silica coating.

Modification of alloys for resin-bonded fixed partial dentures has been suspect since the introduction of the conservative procedure. This study investigated the effect of sandblasting on composite resin-alloy bond strengths with the Silicoating technique. Ag-Pd and Ni-Cr alloys were prepared for casting. The specimens then were sandblasted with 37 microns or 250 microns Al2O3 particles under the following conditions: 3 kg/cm2 for 30 seconds; 5 kg/cm2 for 10 seconds, 30 seconds, and 45 seconds; and 7 kg/cm2 for 30 seconds. After each sandblasting treatment, the surfaces of the alloys were examined with the scanning electron microscope and the wettability of the alloy surfaces was measured. After sandblasting, the alloy surface was silica-coated, and light-cured composite resin then was bonded to the alloy. Specimens were divided, stored in dry air for 1 week, and thermocycled from 4 degrees to 60 degrees C for 10(4) cycles. Bond strength was measured by applying compressive shear stress. It was found that sandblasting made the alloy-water contact angle smaller and wettability greater. The adhesive strength of composite resins with alloys was influenced by sandblasting.

Aluminum Oxide↗

Coating of silicone-based impression materials in a glow-discharge system by acrylic acid plasma.

OBJECTIVES: The main purpose of this study was to demonstrate an increase in the wettability of silicone-based impression materials after coating them with a hydrophilic film in a glow-discharge system. METHODS: Two vinyl polysiloxane impression materials, Extrude (Kerr) and Accuflex (GC America Inc.) were used. Impression specimens were treated in a glow-discharge reactor at a radio frequency of 13.56 MHz at different discharge powers (5-20 W) and exposure times (5-60 min). Surface analysis of the specimens was done by FTIR. Surface contact angles were obtained by a captive-bubble method. These results were analyzed by ANOVA and Duncan's Multiple Range test (p < 0.05). The total number of voids on the die stone casts was observed microscopically. Linear dimensional accuracy, detail reproducibility, and surface hardness of the die stone casts were also determined. A Student t-test was performed for statistical analysis of these parameters (p > 0.05). RESULTS: FTIR spectra indicated that the number of hydroxyl groups on the surfaces increased (p > 0.05) because of the glow-discharge treatment. Contact angle measurements showed an increase (p < 0.05) in surface hydrophilicity. Total void formation in the stone casts decreased. There were no significant differences in the linear dimensional accuracy, detail reproducibility, and hardness, before and after glow-discharge treatment (p > 0.05). SIGNIFICANCE: It was concluded that the surface wettability of the impression materials may be increased by plasma deposition, and therefore, the formation of voids was reduced in the stone casts.

Acrylates↗