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OBJECTIVES: To evaluate the effects of dentin biomodification agents (Proanthocyanidin (PAC), Cardol (CD) and Cardol-methacrylate (CDMA) on dentin hydrophilicity by contact angle measurement, viability of dental pulp stem cells (DPSCs) and nanomechanical properties of the hybrid layer (HL). METHODS: CDMA monomer was synthesized from cardol through methacrylic acid esterification. Human extracted third molars were used for all experiments. For nanomechanical tests, specimens were divided in four groups according to the primer solutions (CD, CDMA, PAC and control) were applied before adhesive and composite coating. Nanomechanical properties of the HL were analyzed by nanoindentation test using a Berkovich probe in a nanoindenter. Wettability test was performed on dentin surfaces after 1 min biomodification and measured by contact angle analysis. Cytotoxicity was assessed by a MTT assay with DPSCs after 48 and 72 h. Data were analyzed with Student's t test or Two-way ANOVA and Tukey HSD test (p < 0.05). RESULTS: CD and CDMA solutions achieved greater hydrophobicity and increased the water-surface contact angles when compared to PAC and control groups (p < 0.05). PAC group showed a greater reduction of elastic modulus in nanoindentation experiments when compared to CD and CDMA groups (p < 0.05) after 4 months of aging. CD inhibited cell proliferation compared to all further materials (p < 0.05), whilst CDMA and PAC indicated no cell cytotoxicity to human DPSCs. SIGNIFICANCE: Cardol-methacrylate provided significantly higher hydrophobicity to dentin and demonstrated remarkable potential as collagen crosslinking, attaining the lowest decrease of HL's mechanical properties. Furthermore, such monomer did not affect pulp cytotoxicity, thereby highlighting promising feasibility for clinical applications.

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In this work, we propose a method to harvest liquid water from water vapor using carbon nanocones. The condensation occurs due to the presence of hydrophilic sites at the nanocone entrance. The functionalization, together with the high mobility of water inside nanostructures, leads to a fast water flow through the nanostructure. We show using molecular dynamics simulations that this device is able to collect water if the surface functionalization is properly selected.

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In this research, changes in several characteristics of partially reduced titania were studied. The reduction process used made it possible to gradually observe changes in the material depending on the amount of reducing agent used. We used NaBH4 to impregnate commercial TiO2 with isopropyl alcohol. Impregnated TiO2 nanoparticles were dried and thermally treated in a nitrogen flow to obtain blue titania samples. Thorough spectroscopic characterization showed that oxygen atoms from hydroxyl groups, as well as from the surface, and the lattice of TiO2 was consumed. This caused changes in the surface and even in the bulk of TiO2 when the amount of reducing agent used was increased. Structural, optical, superficial, and textural characteristics were studied using XRD, Raman, DRS UV-Vis-NIR, Mid-DRIFT, XPS, and nitrogen adsorption/desorption isotherms. A photocatalytic test of the degradation of methylene blue dye was performed. Among different effects on the mentioned characteristics, we found evidence of changes in the surface properties of the blue titania samples and their probable effect on the photocatalytic properties. The reduction process implied a preponderant decrease in the surface hydrophilicity of the reduced samples, an effect shown for the first time in this type of material.

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An on-line system employing switchable-hydrophilicity solvent-based liquid-phase microextraction (SHS-LPME) is described in this work. The method is based on the preconcentration of the species formed between cobalt and the reagent 1-nitroso-2-naphthol (NN), with subsequent detection by digital image colorimetry. The system's operation begins with the on-line mixture of sample, switchable solvent, and an alkaline agent in a reaction coil. Then the mixture is transported to an extraction chamber. The introduction of a proton donor leads to the passage of the solvent to its hydrophobic form, which allows phase separation. The rich phase is then directed to a glass tube, where detection is performed. Octanoic acid, sodium carbonate, and sulfuric acid were used as the extraction solvent, the alkaline agent, and the proton donor, respectively. Under optimized conditions, the method presented a detection limit of 0.8 µg L-1 and an enrichment factor of 41. The precision obtained was 4.8% (20 µg L-1). The accuracy of the method was tested by the analysis of Tomato Leaves certified reference material (NIST 1573a). The method was applied to the determination of cobalt in food, dietary supplements, and water samples. The method is presented as a green alternative and very accessible to the determination of cobalt in the analyzed samples.

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Surface treatments are designed to promote modified implant surfaces with positive interactions with the surrounding living tissues. However, the inadvertent early contact of these surfaces with oral fluids during surgery may lead to undesired conditions affecting osseointegration. This study aimed to investigate the possible alterations in the physico-chemical properties of modified-surfaces caused by early saliva exposure. Titanium (Ti) surfaces were exposed to three different samples of human saliva and later analyzed for protein adhesion, physico-chemical surface alterations, and osteogenic cell-viability. The results indicated that surface roughness was the most significant factor influencing saliva protein adsorption; moreover, hydrophilic surfaces had critically lost their characteristics after contact with saliva. Decreased cell viability was observed in cultures after contact with saliva. Early contact with saliva might negatively influence modified surface properties and local cell viability. Careful surgical insertion of implants with hydrophilic surfaces is recommended, particularly in sites where saliva interaction is prone to occur.

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Micro and nanoscale changes allow the optimization of physico-chemical properties of titanium implant surfaces. Recently UV and plasma treatments have allowed surface hydrophilicity to take increased prominence; however, this beneficial effect is short-lived. The aim of this study is to investigate methodologies post-anodizing treatment to generate and maintain high surface hydrophilicity along with high biocompatibility. Anodized surfaces were characterized regarding physical-chemical properties. Then, surface wettability with nanomorphology was evaluated at different times and with distinct post-treatments: as deposited, with a reactive plasma and UV-light post-treatment, stored in air or deionized (DI) water. Adhesion, alkaline phosphatase (ALP) activity and bone cell viability tests were executed after the incremental treatments. The anodizing process generated a surface with TiO2 nanotubes morphology and micro-roughness. Plasma-treated surfaces resulted in the most hydrophilic samples and this property was maintained for a longer period when those were stored in DI water (angle variation of 7° to 12° in 21 days). Furthermore, plasma post-treatment changed the titanium surface crystalline phase from amorphous to anatase. Anodized surfaces modified by reactive plasma and stored in DI water suggest better hydrophilicity stability, biocompatibility, ALP activity and achievement of crystalline phase alteration, indicating future potential use on biomedical implants.

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The mussel-inspired method has been investigated to modify commercial ultrafiltration membranes to induce antifouling characteristics. Such features are essential to improve the feasibility of using membrane processes in protein recovery from waste streams, wastewater treatment, and reuse. However, some issues still need to be clarified, such as the influence of membrane pore size and the polymer concentration used in modifying the solution. The aim of the present work is to study a one-step deposition of dopamine (DA) and polyethyleneimine (PEI) on ultrafiltration membrane surfaces. The effects of different membrane molecular weight cut-offs (MWCO, 20, 30, and 50 kDa) and DA/PEI concentrations on membrane performance were assessed by surface characterization (FTIR, AFM, zeta potential, contact angle, protein adsorption) and permeation of protein solution. Results indicate that larger MWCO membranes (50 kDa) are most benefited by modification using DA and PEI. Moreover, PEI is primarily responsible for improving membrane performance in protein solution filtration. The membrane modified with 0.5:4.0 mg mL-1 (DA: PEI) presented a better performance in protein solution filtration, with only 15% of permeate flux drop after 2 h of filtration. The modified membrane can thus be potentially applied to the recovery of proteins from waste streams.

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In this study, the use of switchable hydrophilicity solvent with a simple and low-cost lab-made device for the extraction procedure in homogeneous liquid-liquid microextraction is proposed for the first time in the determination of antidepressants in human urine. The antidepressants studied consisted of fluoxetine, amitriptyline, nortriptyline, imipramine, desipramine and sertraline. The optimization of the main parameters that can influence on the extraction efficiency was performed through multivariate approaches. The analytes were separated and identified by gas chromatography coupled to mass spectrometry (GC-MS). The optimal extraction conditions consisted of using N,N-dimethylcyclohexylamine (DMCHA) as the switchable hydrophilicity solvent (SHS), 500 µL of urine sample previously diluted with ultrapure water at 1:1 ratio (v/v), 200 µL of a mixture of SHS:HCl 6 mol L-1 (1:1 v/v), 600 µL of NaOH 10 mol L-1 and 3 min of extraction time. A volume of 40 µL of diphenylamine at concentration of 500 µg L-1 (20 ng) was used as internal standard. The method developed was in-house validated, providing coefficients of determination higher than 0.995 for all analytes, limits of detection (LOD) from 0.02 to 0.88 µg L-1, limits of quantification (LOQ) from 0.05 to 2.92 µg L-1, relative recoveries of 68 to 102%, intra-day precision from 0.5 to 15.9%, inter-day precision from 4.2 to 19.3%, selectivity and robustness. The method proposed was successfully applied in five human urine samples from a Toxicological Information Center located in Porto Alegre (Brazil). The results demonstrated that the µP-SHS-HLLME approach is highly cost-effective, rapid, simple and environmentally-friendly with satisfactory analytical performance.

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Although there are several studies of the ultraviolet (UV) light-mediated photofunctionalization of titanium for use as implant material, the underlying mechanism is not fully understood. However, the results of in vitro and in vivo studies are very encouraging. The use of UV photofunctionalization as a surface treatment on other implant materials, as the Cr-Co-Mo alloy, has not been explored in depth. Using sandblasted Cr-Co-Mo discs, the surface photofunctionalization was studied for ultraviolet A (UVA, 365 nm) and ultraviolet C (UVC, 254 nm), and the surfaces were evaluated for their ability to sustain hydroxyapatite crystal growth through incubation in simulated body fluid for a seven-day period. The variation of the pre- and post-irradiation contact angle and surface composition was determined through the quantification of the weight percentage of Ca and P crystals by the EDAX ZAF method (EDS). Statistically significant differences (p < 0.05) were found for samples irradiated with UVA over 48 h, corresponding with hydrophilic surfaces, and the same result was found for samples exposed to 3 h of UVC. Superhydrophilic surfaces were found in samples irradiated for 12, 24 and 48 h with UVC. The decrease in the carbon content is related with the increase in the surface content of Ca and P, and vice versa over the Cr-Co-Mo surfaces.

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OBJECTIVE: The aim of this preclinical study was to compare histologically and histomorphometrically both sandblasted/acid-etched implant surfaces with or without maintained in an isotonic solution of 0.9% sodium chloride in early stages of osseointegration. MATERIAL AND METHODS: Both implant surfaces were composed of a titanium/aluminum/vanadium alloy (Ti6Al4V-ELI), but they had different surface chemistries: sandblasted/acid-etched titanium surface (FN) or sandblasted/acid-etched surface maintained in an isotonic solution of 0.9% sodium chloride (FA). The surface morphology, topography and chemistry were evaluated by scanning electron microscopy (SEM), confocal microscopy (CM) and X-ray photoelectron spectroscopy (XPS), respectively. Dynamic contact angle (DCA) was employed for wettability evaluation. One implant from each group was placed in the left tibia of twenty healthy, skeletally mature Santa Ines sheep (n = 5). Bone area (BA) and bone-to-implant contact (BIC) were performed on thin sections (30 µm) at 7, 14, 21 and 28 days after implant installation. RESULTS: Despite the roughness and morphology similarities between the groups, at the XPS evaluation, the FA group presented 2.3 times less carbon on the surface (FN: 27.3% and FA: 11.6%), sharply enhanced hydrophilicity and significantly enhanced BA and BIC at 14, 21 and 28 days of healing (P < 0.05) compared with the FN. CONCLUSION: The data suggest that the hydrophilic FA accelerates the BA apposition and BIC interface around the implants during early stages of bone formation, providing highest degree of osseointegration.

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