Leaf wettability, anatomy and ultra-structure of Nothofagus antarctica and N. betuloides grown under a CO2 enriched atmosphere.

Increasing CO2 air concentration may affect wettability, anatomy and ultra-structure of leaves of Patagonian forest species, evergreen and deciduous plants potentially responding differently to such CO2 increases. In this study, we analysed the wettability, anatomy and ultra-structure of leaves of Nothofagus antarctica (deciduous) and N. betuloides (evergreen) grown under high CO2 concentrations. Leaf wettability was affected by increasing CO2, in different directions depending on species and leaf side. In both species, soluble cuticular lipid concentrations per unit leaf area raised with higher CO2 levels. Stomatal parameters (density, size of guard cells and pores) showed different responses to CO2 increasing depending on the species examined. In both species, leaf tissues showed a general trend to diminish with higher CO2 concentration. Cuticle thickness was modified with higher CO2 concentration in N. betuloides, but not in N. antarctica leaves. In both species, chloroplasts were often damaged with the increase in CO2 concentration. Our results show that several surface and internal leaf parameters can be modified in association with an increase in atmospheric CO2 concentration which may very among plant species.

Surface Characteristics and Microbial Adhesion in Polymethylmethacrylate for Denture Base Submitted to Antimicrobial Agents and Cleaning Agents: A Systematic Review.

This review aimed to identify the influence of antimicrobial and cleaning agents on surface characteristics such as surface free energy (SFE) and wettability, and microbial adhesion in polymethylmethacrylate (PMMA) for denture base. The review question, based on PICO, was: "Does intervention with antimicrobial and cleaning agents in PMMA influence the surface free energy, wettability, and consequently the microbial adhesion?" and the protocol was registered in Open Science Framework (osf. io/v3xgn). The search was performed in PubMed, Lilacs, Embase, Scopus, and Science Direct databases, using the terms: ("acrylic resin" OR PMMA) AND (antimicrobial OR antibacterial) AND ("electrostatic interaction" OR surface free energy) AND (biofilm OR "bacteria adhesion"), and resulted in 462 articles, of which 7 were included. The antimicrobials polypara-xylylene, carboxybetaine methacrylate, ethylene glycol methacrylate phosphate, and deposition of F and Ag ions in PMMA influenced the SFE and wettability. Denture cleaners reduced microbial adhesion. Five of the included studies evaluated the microbial adhesion, however, only two observed a direct relationship between SFE, wettability, and microbial adhesion. It was concluded that the intervention with antimicrobial and cleaning agents in PMMA can interfere in SFE and surface wettability, but no correlation was observed between microbial adhesion and these surface characteristics in PMMA.

Curcuminoid-Tailored Interfacial Free Energy of Hydrophobic Fibers for Enhanced Biological Properties.

The ability of mimicking the extracellular matrix architecture has gained electrospun scaffolds a prominent space into the tissue engineering field. The high surface-to-volume aspect ratio of nanofibers increases their bioactivity while enhancing the bonding strength with the host tissue. Over the years, numerous polyesters, such as poly(lactic acid) (PLA), have been consolidated as excellent matrices for biomedical applications. However, this class of polymers usually has a high hydrophobic character, which limits cell attachment and proliferation, and therefore decreases biological interactions. In this way, functionalization of polyester-based materials is often performed in order to modify their interfacial free energy and achieve more hydrophilic surfaces. Herein, we report the preparation, characterization, and in vitro assessment of electrospun PLA fibers with low contents (0.1 wt %) of different curcuminoids featuring π-conjugated systems, and a central ß-diketone unit, including curcumin itself. We evaluated the potential of these materials for photochemical and biomedical purposes. For this, we investigated their optical properties, water contact angle, and surface features while assessing their in vitro behavior using SH-SY5Y cells. Our results demonstrate the successful generation of homogeneous and defect-free fluorescent fibers, which are noncytotoxic, exhibit enhanced hydrophilicity, and as such greater cell adhesion and proliferation toward neuroblastoma cells. The unexpected tailoring of the scaffolds' interfacial free energy has been associated with the strong interactions between the PLA hydrophobic sites and the nonpolar groups from curcuminoids, which indicate its role for releasing hydrophilic sites from both parts. This investigation reveals a straightforward approach to produce photoluminescent 3D-scaffolds with enhanced biological properties by using a polymer that is essentially hydrophobic combined with the low contents of photoactive and multifunctional curcuminoids.

Influence of silica nanocoating on stain susceptibility and superficial integrity of dimethacrylate-based composites.

The aim of this study was to investigate the ability of a novel silica (SiO2 )-based nanocoating approach to extend the superficial integrity of current composites. Cylindrical discs (7 × 2 mm) were produced from nanohybrid and nanofilled composites. Specimens in control groups were not coated, but SiO2 nanocoating was performed on specimens in experimental groups (n = 8). Specimens were stored for 24 h in distilled water at 37°C (baseline) and then artificially aged for 15, 90, or 180 d in a low-pH staining solution. Surface roughness (Ra) was measured using a profilometer, and a goniometer was used to determine surface free energy (SFE). Color change was evaluated by a reflectance spectrophotometer, applying the color distance metric, ΔE00 , according to the Commission Internationale de l'Eclairage (CIE) L*a*b* coordinates. Data were subjected to repeated-measures anova and the Tukey post-hoc test. Composites presented visually perceptible color changes (ΔE00  > 0.81) as early as 15 d of aging, with significantly higher ΔE00 values recorded over time. Nanocoating with SiO2 significantly reduced the SFE of composites at all storage times, and significantly lower Ra values were identified after aging. Nanohybrid and nanofilled composites were susceptible to substantial hydrolytic superficial degradation and staining, which was dramatically attenuated by the proposed SiO2 nanocoating approach. Nanocoating effectively lowered the SFE of composites, thus minimizing water-composite interactions, which contributed to reduced superficial deterioration and lower stain susceptibility over time.

Análise da energia de superfície de fios ortodônticos de diferentes ligas submetidas a exposição de ácidos / Surface energy analysis of orthodontic wires from different alloys subjected to acid exposure

O objetivo deste estudo foi avaliar in vitro a energia de superfície livre e rugosidade de superficie de ligas metálicas sob desafios de soluções ácidas. Para o estudo foram utilizados 270 corpos de prova representados por segmentos de fios retangulares de 0,019" x 0,025" - 3 marcas comerciais (GAC, American Orthodontics e Orthoclassic) foram divididas em 3 grupos de diferentes soluções sendo 90 para água deionizada, 90 para ácido cítrico e 90 para ácido fosfórico, dentro dos grupos de solução dividiu-se em 30 de aço inoxidável, 30 de níquel titânio e 30 titânio molibdênio. Cada grupo de análise (n=10) foi imerso em meio a cada solução por 72 horas a 37º C e agitação de 130 rpm. A análise de ESL foi avaliada através do dispositivo goniômetro para interpretação do ângulo de contato avaliando a variável. As médias foram submetidas ao teste ANOVA e as comparações ao Tukey a 5% de significância. A superfície da liga de TMA apresentou maior valor de energia de superfície (p<0,001). Concluiu-se que a liga de TMA apresentou maior energia de superfície e o desafio de ácido cítrico provocou as maiores alterações(AU)

The objective of this study was to evaluate in vitro the free surface energy and surface roughness of metallic alloys under challenges of acid solutions. For the study, 270 pieces represented by 0.019 "x 0.025" rectangular strands were used - 3 commercial brands (GAC, American Orthodontics and Orthoclassic) were divided into 3 groups of different solutions, 90 for deionized water, 90 for acid citric acid and 90 to phosphoric acid, within the solution groups was divided into 30 stainless steel, 30 nickel titanium and 30 titanium molybdenum. Each assay group (n = 10) was immersed in each solution medium for 72 hours at 37 ° C and shaking at 130 rpm. The ESL analysis was evaluated through the goniometer device for the interpretation of the contact angle evaluating the variable. The means were submitted to the ANOVA test and the Tukey comparisons at 5% significance. The surface of the TMA alloy had a higher surface energy value (p <0.001). It was concluded that the TMA alloy presented higher surface energy and the citric acid challenge caused the greatest changes(AU)

Relationship between Surface Properties and In Vitro Drug Release from Compressed Matrix Containing Polymeric Materials with Different Hydrophobicity Degrees.

This work is the continuation of a study focused on establishing relations between surface thermodynamic properties and in vitro release mechanisms using a model drug (ampicillin trihydrate), besides analyzing the granulometric properties of new polymeric materials and thus establishing the potential to be used in the pharmaceutical field as modified delivery excipients. To do this, we used copolymeric materials derived from maleic anhydride with decreasing polarity corresponding to poly(isobutylene-alt-maleic acid) (hydrophilic), sodium salt of poly(maleic acid-alt-octadecene) (amphiphilic), poly(maleic anhydride-alt-octadecene) (hydrophobic) and the reference polymer hydroxyl-propyl-methyl-cellulose (HPMC). Each material alone and in blends underwent spectroscopic characterization by FTIR, thermal characterization by DSC and granulometric characterization using flow and compaction tests. Each tablet was prepared at different polymer ratios of 0%, 10%, 20%, 30% and 40%, and the surface properties were determined, including the roughness by micro-visualization, contact angle and water absorption rate by the sessile drop method and obtaining Wadh and surface free energy (SFE) using the semi-empirical models of Young-Dupré and  Owens-Wendt-Rabel-Käelbe (OWRK), respectively. Dissolution profiles were determined simulating physiological conditions in vitro, where the kinetic models of order-zero, order-one, Higuchi and Korsmeyer-Peppas were evaluated. The results showed a strong relationship between the proportion and nature of the polymer to the surface thermodynamic properties and kinetic release mechanism.

Relationship between Surface Properties and In Vitro Drug Release from a Compressed Matrix Containing an Amphiphilic Polymer Material.

The performance of compressed tablet drug delivery systems made using polymeric materials depend on multiple factors, such as surface properties like contact angle, surface free energy and water absorption rate, besides the release mechanisms driven by the kind of polymer used. Hence, it should be possible to establish a relationship between the surface properties and the drug release kinetics. Compressed tablets with different proportions of poly(maleic acid-alt-octadecene) potassium salt (0%, 10%, 20%, 30% and 40%) were prepared. Blends of a model drug (ampicillin trihydrate) and the polymer material were analyzed by DSC. The surface properties of the tablets were determined by the sessile drop method, while the surface energy was determined using the semi-empirical Young-Dupre, Neumann and OWRK models. The release profiles were determined simulating in vitro conditions (buffer solutions pH 1.2 and pH 7.4 with ionic strength of 1.5 M at 37 °C (310.15 K)). A kinetic analysis of the dissolution profiles using different models (zero order, first order, Higuchi and Korsmeyer-Peppas) was realized. The results showed a significant effect of the proportion of polymer in both the surface properties of the tablets and the dissolution release, indicating a relationship between the kinetic and thermodynamic properties.

Effect of Collagen Matrix Saturation on the Surface Free Energy of Dentin using Different Agents.

INTRODUCTION: The surface free energy of conditioned-dentin is one of the factors that interfere with monomeric infiltration of the interfibrillar spaces. Saturation of the tooth matrix with different substances may modulate this energy and, consequently, the wettability of the dentin. AIM: To evaluate the influence of different substances used to saturate conditioned-dentin on surface free energy (SFE) of this substrate. MATERIALS AND METHODS: Dentin blocks (4 × 7 × 1 mm, n = 6/ group), obtained from the roots of bovine incisors, were etched using phosphoric acid for 15 seconds, rinsed and gently dried. The surfaces were treated for 60 seconds with: ultra-purified water (H20-control); ethanol (EtOH), acetone (ACT), chlorhexidine (CHX), ethylenediaminetetraacetic acid (EDTA); or sodium hypochlorite (NaOCl). The tooth surfaces were once again dried with absorbent paper and prepared for SFE evaluation using three standards: water, formamide and bromonaphthalene. Analysis of variance (ANOVA) and Dunnet's tests (a = 0.05) were applied to the data. RESULTS: Ethylenediaminetetraacetic acid was the only substance that caused a change to the contact angle for the standards water and formamide, while only EtOH influenced the angles formed between formamide and the dentin surface. None of the substances exerted a significant effect for bromonaphtha-lene. In comparison to the control, only EDTA and NaOCl altered both polar components of the SFE. Total SFE was increased by saturation of the collagen matrix by EDTA and reduced when NaOCl was used. CONCLUSION: Saturation of the collagen matrix by EDTA and EtOH changed the surface free energy of the dentin. In addition, the use of NaOCl negatively interfered with the properties evaluated. CLINICAL SIGNIFICANCE: The increase of surface free energy and wettability of the dentin surface would allow higher penetration of the the adhesive system, which would be of importance to the clinical success of resin-dentin union.

Plasma proteins in the acquired denture pellicle enhance substrate surface free energy and Candida albicans phospholipase and proteinase activities.

AIM: The objective of the present study was to determine if blood plasma proteins could change the proteome of the acquired denture pellicle by label-free quantitative proteomics. As pellicle proteome modulates the interaction between substrates and Candida cells, we investigated its effect on the surface free energy (SFE) of the coated resin and on Candida albicans phospholipase and aspartyl proteinase activities. METHODS: Poly(methylmethacrylate) discs were exposed to saliva (control) or saliva enriched with blood plasma (experimental group). The pellicle proteome was analyzed by mass spectrometry coupled with liquid chromatography. SFE was determined by acid-base technique. After biofilm formation, phospholipase and proteinase activities were determined accordingly to classic plate methods. Data were analyzed by two-way anova and Tukey test (P < 0.05). RESULTS: α-Amylase, cystatins, mucins, and host-immune system proteins were the main proteins identified in the control group. Fibrinogen and albumin were observed only in the experimental group. Coated discs of the experimental group presented an increased SFE (P < 0.05). For both enzymes tested, the experimental group showed higher proteolytic activity (P < 0.001). CONCLUSION: Blood plasma changes the proteome of the acquired denture pellicle, increasing surface free energy and the activity of Candida albicans phospholipase and aspartyl proteinase.

Dynamics of the interaction between body fluid and Ti cp: the influence of surface functionalization in the first stages of osseointegration

INTRODUCTION: Regenerative therapies using biomaterials require accurate information on interactions between the implanted material and the human body. To improve the process of bone regeneration it is necessary to obtain a better understanding of the influence of the surfaces on the early stages of osseointegration. This work aims to investigate the dynamic interaction between simulated body fluid (SBF) and titanium surfaces (Ti cp) immediately after their first contact. METHODS: Ti cp samples were passed through physicochemical treatments after immersion in acid solution, alkaline solution and solutions containing TiO2 and Ca2+, to obtain three different surfaces. These were characterized by electron microscopy and free energy estimates. The evaluation of the interaction with SBF was performed by measuring the dynamic contact angles after contacting the surfaces. RESULTS: The effects of SBF wettability were more significant on surfaces according to high energy estimates. A comparative analysis of the three types of surfaces showed that fluid spreading was greater in samples with greater polar components, indicating that the surface nature influences interactions in the early stages of osseointegration. CONCLUSION: The results indicate the influence of polar interactions in the dynamic wettability of the SBF. It is possible that these interactions can also influence cellular viability on surfaces. Based on these results, new experiments are being designed to improve the presented methodology as a tool for the evaluation of biomaterials without the need for in vivo experiments.