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PubMed2006

The wettability of intrasynovial and extrasynovial tendons.

PURPOSE: The surface properties of biologic materials are important to their observed physiochemical responses, mechanical interactions, and compatibility with other materials. The purpose of this study was to characterize further the surface properties of canine tendons, specifically how they interface with fluids--that is, their wettability. METHODS: Drop-shape analysis was used to study contact angles on intrasynovial and extrasynovial tendon surfaces. This standard goniometric method was used to estimate tendon-wettability properties. RESULTS: This study showed that extrasynovial tendon portions (particularly the dorsal sides) are more wettable than intrasynovial tendons. We also showed that trypsin digestion of tendon surfaces increases their wettability. CONCLUSIONS: The wettability differences between intrasynovial and extrasynovial canine tendons may help to explain known differences in the propensities of these 2 different tendon types to form adhesions after surgery.

Absorption↗
PubMed1999

Interaction of fibroblast cells on poly(lactide-co-glycolide) surface with wettability chemogradient.

Chemogradient surfaces whose properties are changed gradually along the sample length are of particular interest for the basic studies of the interaction between biological species and surfaces since the effect of a selected property can be examined in a single experiment on one surface. A wettability chemogradient on the poly(L-lactide-co-glycolide) (PLGA) films by treating them in air with corona from a knife-type electrode whose power increases gradually along the sample length. The PLGA surfaces oxidized gradually with the increasing corona power, and the wettability chemogradient was created on the surfaces as evidenced by the measurement of water contact angles and electron spectroscopy for chemical analysis. The wettability chemogradient PLGA surfaces prepared were used to investigate the interaction of fibroblast cells in terms of the surface hydrophilicity/hydrophobicity of PLGA surface. The cells adhered and grown on the chemogradient surface along the sample length were counted and observed by scanning electron microscopy. It was observed that the cells were adhered, spread, and grown more onto positions with moderate hydrophilicity of the wettability chemogradient PLGA surface than onto the more hydrophobic or hydrophilic positions. The maximum adhesion and growth of the fibroblast cells appeared at around water contact angle of 55 degrees. It seems that the wettability plays important roles for cell adhesion, orientation, spreading and growth on the PLGA surface. It might be that this surface modification technique can be used for improving the adhesion and growth of cell onto PLGA film and scaffolds, and can be applicable in the area of the tissue engineering.

3T3 Cells↗
PubMed1989

Effects of "wettability" of biomaterials on culture cells.

New objectives of the development of biomaterials in recent years include how to control surface characteristics of materials and the attachment of cells to implant sites. This study clarified the effect of "wettability" of materials on culture cells, with wettability being expressed by the contact angle of the material to the water. First, low-temperature plasma treatment was administered so that samples of the same materials and shapes could be obtained, differing only in wettability. The contact angles at the surfaces of the samples and their surface roughness were then measured, and surfaces were analyzed by ESCA. For clarification of the biological response of the cell to wettability, attachment of connective tissues and epithelial-tissue-originated established cell lines to the material and its cell spreading were investigated in each test sample. As a result, it was found that the contact angle of each material used in the experiment affected both the cell attachment and spreading rates; thus, wettability of biomaterials is considered to be an important parameter of biological effect at the cell level.

Animals↗
PubMed2006

Effect of various treatment and glazing (coating) techniques on the roughness and wettability of ceramic dental restorative surfaces.

Surface treatment procedures such as grinding and polishing are needed to provide the ceramic dental restorative materials with proper fitting and occlusion. The treated surfaces are customarily glazed to improve the strength and smoothness. Though smoothness and wetting of the dental surfaces are important to minimize bacterial plaque retention, influence of the surface treatment and glazing procedures on the final surface roughness and its correlation to wettability are overlooked. In this work, effect of various treatment (diamond fraising, stoning, sanding and aluminum oxide and rubber polishing) and glazing (auto and overglazing) techniques on the final roughness and the resulting wettability of dental ceramic surfaces were investigated using scanning electron microscopy (SEM) observations and atomic force microscopy (AFM) scans, 75 scans per sample. The surfaces were characterized and assigned an average roughness measure, R(a). The wettability of the same surfaces was evaluated using micro-contact angle measurements (25 micro-bubbles placed on a grid on each surface) to correlate the final surface roughness and wettability. The results show that overglazing prevails over surface irregularities from different treatment procedures and provides homegeneously smooth surfaces with mean R(a)<10 nm. It also produces uniformly wetted surfaces with low contact angles around 20 degrees . The autoglazed surfaces are less smooth (mean R(a) around 50 nm) and displays sporadic topographic irregularities. They display larger and less uniform contact angles ranging between 35 degrees and 50 degrees . The results suggest that overglazing should be preferred after surface treatment to obtain a smooth and well-wetted dental ceramic surface.

Aluminum Silicates↗
PubMed2005

Prediction of two-phase capillary pressure-saturation relationships in fractional wettability systems.

Capillary pressure/saturation data are often difficult and time consuming to measure, particularly for non-water-wetting porous media. Few capillary pressure/saturation predictive models, however, have been developed or verified for the range of wettability conditions that may be encountered in the natural subsurface. This work presents a new two-phase capillary pressure/saturation model for application to the prediction of primary drainage and imbibition relations in fractional wettability media. This new model is based upon an extension of Leverett scaling theory. Analysis of a series of DNAPL/water experiments, conducted for a number of water/intermediate and water/organic fractional wettability systems, reveals that previous models fail to predict observed behavior. The new Leverett-Cassie model, however, is demonstrated to provide good representations of these data, as well as those from two earlier fractional wettability studies. The Leverett-Cassie model holds promise for field application, based upon its foundation in fundamental scaling principles, its requirement for relatively few and physically based input parameters, and its applicability to a broad range of wetting conditions.

Environmental Pollutants↗
PubMed1999

Wettability of silicone rubber maxillofacial prosthetic materials.

STATEMENT OF PROBLEM: Maxillofacial prosthetic materials that contact skin or mucosa should have good wettability. A material that is easily wetted will form a superior lubricating layer between the supporting tissues and, thus, reduce friction and patient discomfort. The surface energy of a maxillofacial prosthetic material will give an indication of the amount of energy available for adhesion and of the susceptibility of the material to bacterial adhesion. PURPOSE: This study evaluated the wettability and surface energies of a range of commercially available silicone rubber maxillofacial prosthetic materials. MATERIAL AND METHODS: Contact angles and surface energies were measured by using a dynamic contact angle measuring technique. Four commonly used silicone maxillofacial materials were tested and their properties compared with those of an acrylic resin denture base material and a widely used denture soft lining material. RESULTS: There were no significant differences in the wettability of the silicone rubber materials. All materials were significantly less wetted than the denture acrylic resin material. There were no significant differences in the surface energies of the silicone rubber materials, but all were significantly lower than denture acrylic resin material. CONCLUSIONS: The Cahn dynamic contact angle analyzer was a quick and reproducible method for determining the contact angles and surface energies of maxillofacial materials. Further work is needed to improve the wettability of silicone rubber materials used for maxillofacial prostheses, thus, reducing their potential to produce friction with tissues.

Acrylic Resins↗
PubMed2001

Surface roughness and wettability of enamel and dentine surfaces prepared with different dental burs.

The aim of dental adhesive restorations is to produce a long lasting union between the restoration and the tooth structure. This bond depends on many variables including the geometry of the preparation and the type of bonding agent or luting cement. It is therefore suggested that the topography of the tooth surface may influence the wettability and the bonding quality of adhesive systems. This study measured the surface roughness and wettability of enamel and dentine after preparation with different dental burs. The mesial and distal surfaces of 15 extracted sound human premolar teeth were prepared with a tungsten carbide crown bur, a diamond bur and a tungsten carbide finishing bur and finished in enamel or dentin, respectively. The prepared surfaces were analysed with a surface profilometer and scanning electron microscopy (SEM). The contact angle of distilled water on each of the prepared surfaces was used as the measure of wettability. The differences in average surface roughness (Ra) were significant between the rotary instrument groups, as revealed by a two-way ANOVA test. No differences were detected between enamel and dentine surfaces prepared with the same type of dental bur. The smoothest surfaces were those completed with tungsten carbide finishing burs. The diamond bur preparations were intermediate in the roughness assessment and the tungsten carbide crown burs gave the roughest surfaces. There were no significant differences in the contact angle measurements for the various groups. It was concluded that the surface roughness of enamel and dentine prepared by different rotary instruments had no significant influence on the wettability of distilled water on these surfaces.

Analysis of Variance↗
PubMed1996

Studies on the biocompatibility of materials: fibroblast reorganization of substratum-bound fibronectin on surfaces varying in wettability.

The ability of human fibroblasts to remove and reorganize fibronectin (FN) bound on material surfaces was studied as a novel feature of material surface biocompatibility. Other traditional parameters of biocompatibility analyzed included cell spreading, clustering of fibronectin receptors into focal adhesions, development of stress fibers, and cell growth. Five different materials with surface wettability ranging from hydrophilic (underwater contact angle 25 degrees) to hydrophobic (underwater contact angle 111 degrees) were used, i.e., clean glass (GLASS), aminopropylsilane (APS), octadecylsilane (ODS), polylactate (PL), and silicone (SI). When cells were cultured on these materials in serum-containing medium, formation of FN receptor-rich focal adhesions and actin stress fibers were more evident on the hydrophilic surfaces (GLASS and APS) compared to the hydrophobic ones (PL, ODS, and SI). Cell growth showed a similar pattern, that is, increased cell proliferation with increasing material surface wettability. Preadsorption of FN on the material surfaces increased subsequent cell spreading and cytoskeletal reorganization on hydrophobic surfaces except SI. Removal and reorganization of FN from the material surfaces into extracellular matrixlike structures occurred on GLASS but not on less wettable surfaces, suggesting that this removal/reorganization process may be more sensitive to changes in surface wettability than other parameters of biocompatibility.

Actins↗
PubMed2006

Wettability modification and the subsequent manipulation of protein adsorption on a Ti6Al4V alloy by means of CO2 laser surface treatment.

Improvements in the wettability of the Ti6Al4V alloy following CO(2) laser treatment were identified as being due mainly to the increase in surface roughness, surface oxygen content and surface energy of the material. Untreated and mechanically roughened samples had higher amounts of adsorbed albumin and lower amounts of adsorbed fibronectin than CO(2) laser treated samples. Moreover, as the wettability of the Ti6Al4V alloy increased the adsorbed amounts of fibronectin increased, while the adsorbed amounts of albumin decreased--indicating the controllability of the CO(2) laser process. From this finding it is possible to assert that the wettability of the Ti6Al4V alloy was the prime influence on the observed changes in in vitro protein adsorption. Further, the noted considerable change in the polar component of surface energy, [Formula: see text], on the protein adsorption implied that the protein adsorption on the Ti6Al4V alloy was probably due to the polar and chemical interactions. This work has demonstrated that CO(2) laser radiation could be a suitable means to modify the wettability of the Ti6Al4V alloy and thereby manipulate protein adsorption and consequently render the material more bone cell responsive.

Adhesiveness↗
PubMed2006

Dynamic wettability of pHEMA-based hydrogel contact lenses.

Standard methods of contact angle analysis include sessile drop, captive bubble and Wilhelmy plate techniques; however, these methodologies are not particularly well suited for assessing the wettability of the surfaces of formed hydrogel contact lenses. This paper describes two methodologies that are adaptations of previously described techniques. The maximum adherent force method is an adaptation of the dynamic Wilhelmy plate technique that allows the assessment of whole, finished contact lenses. The dynamic photographic method allows the simultaneous assessment of the front and back surfaces of strip samples for the assessment of advancing and receding contact angles. Lenses investigated were made from polyhydroxyethyl methacrylate, hydroxyethyl methacrylate/methacrylic acid and hydroxyethyl methacrylate/glycerol methacrylate. The lenses were manufactured by lathing, spin-casting or cast-moulding techniques. Overall, both techniques demonstrated few differences between the wettability of different lens materials and no differences between materials of the 'same' lens type but manufactured by different methods. These findings are consistent with the results of clinical studies, which have shown little difference between contact lens surface wettability in vivo, which may be due to the apparent natural surface wettability-enhancing properties of the pre-lens tear film.

Biocompatible Materials↗
PubMed1996

Fibronectin matrix formation by human fibroblasts on surfaces varying in wettability.

The spatial organization of extracellular fibronectin on biomaterial surfaces might be important for interaction with tissue cells. In previous investigations we have demonstrated that hydrophilic materials bind preadsorbed fibronectin that can easily be reorganized by fibroblasts in a specific matrix-like structure, while on less wettable materials (possessing water contact angles above 60 deg) the cells were unable to do this. As the cells continuously produce their fibronectin matrix, we tried in this study to answer the question of how the surface wettability of biomaterials influences the endogenous fibronectin matrix formation and its subsequent organization on the substrate. We cultured fibroblasts for 72 h on five different wettable surfaces: glass, aminopropyltriethoxysilane, pellethane, polyvinylchloride, and silicone, with water-contact angles gradually ranging from 25 to 105 deg. We demonstrated that the decreasing wettability of the materials significantly reduced endogenous fibronectin deposition on the substratum. Moreover, fibrillar organization of fibronectin appeared only on relatively hydrophilic glass and APS substrate, while on more hydrophobic materials like PVC and SI, cells secreted some fibronectin but were not able to organize it into a fibronectin matrix. These results were correlated with an altered cell morphology and spreading on these materials. In addition, an ELISA method has been implemented to quantify fibronectin matrix formation as a possible measure of the biocompatibility of materials, where a clear relation has been found between fibroblast growth and fibronectin matrix formation.

Adsorption↗
PubMed1996

Polymeric membranes for hybrid liver support devices: the effect of membrane surface wettability on hepatocyte viability and functions.

Extracorporeal therapies based on membrane hybrid liver support devices using primary hepatocytes are an interesting approach to the treatment of acute hepatic failure. In such devices, semipermeable polymeric membranes are effectively used as immunoselective barriers between a patient's blood and the xenocytes in order to prevent the immune rejection of the graft. The membranes may act also as the substratum for cell adhesion, thus favouring the viability and functions of anchorage-dependent cells such as the hepatocytes. Membrane cytocompatibility is expected to depend on the surface properties of the polymer, such as its morphology and its physico-chemical properties. In this paper, we report our investigation on the effect of the surface wettability of membranes on hepatocyte viability and functions. Polypropylene microporous membranes were modified to increase their surface wettability and were used as substrata for rat hepatocyte adhesion culture. Isolated hepatocytes were also cultured on collagen as a reference substratum. Hepatocyte viability generally improved as the cells were cultured on more wettable membranes. In agreement with the viability data, the increasing wettability of the membrane surface also improved some metabolic functions.

Animals↗
PubMedDate not supplied

Hydrophilic poly(vinyl siloxane) impression materials: dimensional accuracy, wettability, and effect on gypsum hardness.

Three hydrophilic poly(vinyl siloxane) impression materials, containing an intrinsic surfactant, were compared with a hydrophobic poly(vinyl siloxane) and a polyether impression material. The hydrophobic poly(vinyl siloxane) material was dimensionally more accurate than the hydrophilic poly(vinyl siloxane) in two of three measured dimensions, but the difference was small. The polyether material was the most wettable, and the hydrophilic poly(vinyl siloxane) were more wettable than the hydrophobic poly(vinyl siloxane). However, when a topical surfactant was used, no difference in wettability was noted between the hydrophilic and hydrophobic poly(vinyl siloxane), and their wettability was comparable to the polyether material, indicating that the topical surfactant was more effective than the intrinsic surfactants. Stone dies made from the hydrophobic poly(vinyl siloxane) material were harder than those obtained from the other materials.

Analysis of Variance↗
PubMed1999

Improved wettability of an experimental silicone rubber denture soft lining material.

The purpose of this study was to improve the wettability of an experimental silicone rubber soft lining material (Sildent) to increase patient comfort. Sildent was modified by the addition of polyalkylene oxide poly(dimethylsiloxane) surfactants. The various surfactants were added directly to the polymeric matrix in the quantities 5, 10, 20% w/w. The surfactants were also added to a one part silicone sealant, which was then painted onto the surface of already cured Sildent. Contact angle measurements were made on samples using a dynamic contact angle analyzer. Results showed that incorporation of surfactants A (Silwet L7600) and B (Silwet L7607) effectively improved the wettability of Sildent. This improvement was still evident after 6 months storage in distilled water at 37 degrees C suggesting retention of the surfactants matrix via physio-chemical bonding. Formulations with surfactants added directly to the matrix showed unacceptable water absorption after 2 months in distilled water. Samples with surfactant charged sealant painted on the surface showed a lower water absorption. In conclusion, Sildent formulations modified with polyalkylene silicone surfactants showed improved wettability compared to unmodified Sildent. Further work is needed to reduce water uptake and determine the effect on key mechanical properties.

Catalysis↗
PubMed1994

Adhesion of human peripheral blood lymphocytes is dependent on surface wettability and protein preadsorption.

The influence of surface wettability and preadsorption of plasma proteins on cell adhesion was studied using human peripheral blood lymphocytes (PBL). Hydrophilic glass and hydrophobic octadecyl glass were used as model surfaces with known wettability. The adhesion of PBL was investigated under non-flow conditions that are considered as a model for the adhesion of migrating lymphocytes in the tissue. Furthermore, adhering lymphocytes were exposed to increasing shear forces to investigate the detachment under laminar flow conditions to simulate the situation during blood flow. The proteins used in this study were attachment proteins such as fibrinogen, fibronectin and vitronectin. Human serum albumin was used as a control. It was found under both conditions (static and dynamic) that PBL adhesion was strongly influenced by the wettability of the surfaces. Furthermore, it was shown that the properties of the underlying surface influenced the interaction between preadsorbed attachment proteins and PBL.

Blood Proteins↗
PubMed1996

Studies on cell-biomaterial interaction: role of tyrosine phosphorylation during fibroblast spreading on surfaces varying in wettability.

In a previous study we observed that protein tyrosine phosphorylation was significantly diminished in the focal adhesions of human fibroblasts attached on a hydrophobic surface in comparison with hydrophilic glass. This result raises the possibility that the tyrosine phosphorylation pathway may be involved in the regulation of cell-biomaterial interaction. To learn more about the interaction of anchorage-dependent cells with biomaterials, four different materials with wettability ranging from hydrophilic (water contact angle 25 degrees) to hydrophobic (water contact angle 111 degrees) were investigated, i.e. clean glass (glass), aminopropylsilane (APS), octadecylsilane (ODS) and silicone (SI). Immunofluorescence microscopy revealed increased stress formation and fibronectin (FN) receptor-rich focal adhesions for fibroblasts attached on more hydrophilic surfaces (glass and APS) in comparison to the relatively hydrophobic materials (ODS and SI). Phosphorylation of tyrosine residues, also studied by immunofluorescence microscopy, was considerably higher on glass and APS, lower for ODS, negligible for SI, and was found to colocalize with FN receptor-rich focal adhesions. Preadsorption of FN tended to restore cell adhesion and spreading on the hydrophobic ODS and SI. Quantitative data on cell proliferation and tyrosine phosphorylation showed moderate wettable material maximum values for APS, followed by glass. ODS and SI, demonstrating a non-linearity of these parameters with the wettability of materials. Interestingly, the preadsorption of FN increased both parameters, particularly for the hydrophobic materials ODS and SI. Phosphorylation of tyrosine on FN-coated substrata was corroborated by the accessibility of binding sites estimated by ELISA using polyclonal and monoclonal FN antibodies. Our results suggest that measurement of the phosphotyrosine activity of cells may be a sensitive parameter for the ability of biomaterials to support the attachment and proliferation of cells.

Adsorption↗
PubMed2004

Impact of lipopolysaccharide coating on clay particle wettability.

Impact of lipopolysaccharide coating on kaolinite and Na-montmorillonite wettability was investigated. Kaolinite had greater diiodomethane contact angles, smaller water and formamide contact angles than Na-montmorillonite. After lipopolysaccharide coating, diiodomethane and formamide contact angles decreased, while water contact angles increased for both kaolinite and Na-montmorillonite. The decrease and increase in liquid contact angles after lipopolysaccharide coating were most pronounced for lipopolysaccharide extracted from Pseudomonas aeruginosa, followed by Pseudomonas fluorescens and Echerichia coli. Clay particle wettability was determined by particle surface thermodynamic properties. Both kaolinite and Na-montmorillonite exhibited a monopolar surface and the monopolarity decreased after lipopolysaccharide coating, indicating an increase in hydration or surface wetness. The origins of interactions of clay particles with water molecules were discussed and related to clay particle water wettability.

Aluminum Silicates↗
PubMed2005

Dynamic wettability properties of a soft contact lens hydrogel.

The wettability of poly[2-hydroxyethyl methacrylate-co-methacrylic acid] (pHEMA-MAA) soft contact lenses was investigated in the absence and presence of block copolymer surfactants and lysozyme using the sessile drop method. The advancing dynamic contact angles (Thetaw/a) values are reported for water as a function of sequential wetting and drying cycles. The Thetaw/a values for the pHEMA-MAA in the absence of surfactant and lysozyme increased from approximately 20 degrees to 100 degrees as the number of cycles increased from two to ten, and they were independent of the pHEMA-MAA bulk water content. The change from the highly hydrophilic to hydrophobic pHEMA-MAA surface could not be reversed using the sequential wetting and drying cycles even under repeated exposures to saline solution. The effect of block copolymer surfactants with different molecular weights (MW) and hydrophilic-lipophilic balance (HLB) values on the pHEMA-MAA wettability were also studied. Low Theta(w/a) values were observed for pHEMA-MAA hydrogels that were treated with T1304 (MW 10500, HLB 14) and T904 (MW 6700, HLB 15). The surface tension data indicated that these surfactants were incompletely desorbed from the pHEMA-MAA and that the rate of desorption was slow in the timescale of the cycling experiments. Comparatively, poor wettability was observed for pHEMA-MAA surfaces presoaked in T304 (MW 1650, HLB 16) and T1107 (MW 15000, HLB 24) as Thetaw/a values greater than 90 degrees were measured for these surfactants. The surface tension data indicated that the rate of desorption of T304 and T1107 from the pHEMA-MAA was rapid and that they had a low affinity to the pHEMA-MAA. High contact angles were observed for the pHEMA-MAA hydrogels treated with lysozyme and also for the T1107 presoaked pHEMA-MAA that was also treated with lysozyme. Zero wetting angles throughout the sequential cycling were observed for the T1304 pre-treated pHEMA-MAA that had been treated with lysozyme. These results suggested that the adsorbed lysozyme on the pHEMA-MAA hydrogel had no significant influence on its wetting properties when the hydrogel was pre-treated with T1304.

Contact Lenses, Hydrophilic↗