Performance of self-etching adhesives on caries-affected primary dentin treated with glutaraldehyde or silver diamine fluoride.

OBJECTIVES: to evaluate the quality and stability of adhesive interfaces established by self-etching adhesives on caries-affected primary dentin (CAD) treated with glutaraldehyde (GA) or silver diamine fluoride (SDF). METHODS: 42 primary molars were exposed to a microbiological caries-inducing protocol and divided into 6 groups according to the adhesive system (Clearfil SE - CL or FL Bond II - FL) and pretreatment (water, GA or SDF) applied on CAD. One tooth from each group was analyzed for surface modification using infrared spectroscopy. Crowns were restored with resin composite (n = 36) and cut into beams and slices. The beams were subjected to microtensile testing, Raman spectroscopy and SEM after 24 h and 6 months of storage. The slices were analyzed using Micro-Raman spectroscopy to determine the diffusion zone thickness (DZ) in each period. Data were analyzed by ANOVA and Tukey or Kruskal-Wallis and Dunn tests (α = 0.05%). RESULTS: SDF reduced the immediate bond strength for both adhesives. The control groups showed a decrease in BS after 6 months in artificial saliva. GA increased immediate DZ for FL, while SDF had the opposite effect on CL. GA decreased the DZ for FL at 6 months. There was a predominance of adhesive failures with areas of cohesive dentin fractures within control groups. SIGNIFICANCE: Modifications caused by dentin surface treatments may directly affect the performance of adhesive systems and the quality and stability of adhesive restorations.

Perfusion and Ultrasonication Produce a Decellularized Porcine Whole-Ovary Scaffold with a Preserved Microarchitecture.

The application of decellularized scaffolds for artificial tissue reconstruction has been an approach with great therapeutic potential in regenerative medicine. Recently, biomimetic ovarian tissue reconstruction was proposed to reestablish ovarian endocrine functions. Despite many decellularization methods proposed, there is no established protocol for whole ovaries by detergent perfusion that is able to preserve tissue macro and microstructure with higher efficiency. This generated biomaterial may have the potential to be applied for other purposes beyond reproduction and be translated to other areas in the tissue engineering field. Therefore, this study aimed to establish and standardize a protocol for porcine ovaries' decellularization based on detergent perfusion and ultrasonication to obtain functional whole-ovary scaffolds. For that, porcine ovaries (n = 5) were perfused with detergents (0.5% SDS and 1% Triton X-100) and submitted to an ultrasonication bath to produce acellular scaffolds. The decellularization efficiency was evaluated by DAPI staining and total genomic DNA quantification. ECM morphological evaluation was performed by histological, immunohistochemistry, and ultrastructural analyses. ECM physico-chemical composition was evaluated using FTIR and Raman spectroscopy. A cytocompatibility and cell adhesion assay using murine fibroblasts was performed. Results showed that the proposed method was able to remove cellular components efficiently. There was no significant ECM component loss in relation to native tissue, and the scaffolds were cytocompatible and allowed cell attachment. In conclusion, the proposed decellularization protocol produced whole-ovaries scaffolds with preserved ECM composition and great potential for application in tissue engineering.

Classification and Prediction by Pigment Content in Lettuce (Lactuca sativa L.) Varieties Using Machine Learning and ATR-FTIR Spectroscopy.

Green or purple lettuce varieties produce many secondary metabolites, such as chlorophylls, carotenoids, anthocyanins, flavonoids, and phenolic compounds, which is an emergent search in the field of biomolecule research. The main objective of this study was to use multivariate and machine learning algorithms on Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR)-based spectra to classify, predict, and categorize chemometric attributes. The cluster heatmap showed the highest efficiency in grouping similar lettuce varieties based on pigment profiles. The relationship among pigments was more significant than the absolute contents. Other results allow classification based on ATR-FTIR fingerprints of inflections associated with structural and chemical components present in lettuce, obtaining high accuracy and precision (>97%) by using principal component analysis and discriminant analysis (PCA-LDA)-associated linear LDA and SVM machine learning algorithms. In addition, PLSR models were capable of predicting Chla, Chlb, Chla+b, Car, AnC, Flv, and Phe contents, with R2P and RPDP values considered very good (0.81−0.88) for Car, Anc, and Flv and excellent (0.91−0.93) for Phe. According to the RPDP metric, the models were considered excellent (>2.10) for all variables estimated. Thus, this research shows the potential of machine learning solutions for ATR-FTIR spectroscopy analysis to classify, estimate, and characterize the biomolecules associated with secondary metabolites in lettuce.

Dynamics of the natural genesis of ß-TCP/HAp phases in postnatal fishbones towards gold standard biocomposites for bone regeneration.

The search for gold-standard materials for bone regeneration is still a challenge in reconstruction surgery. The ratio between hydroxyapatite (HAp) and ß-tricalcium phosphate (ß-TCP) in biphasic calcium phosphate ceramics (BCPs) is one of the most important factors in osteoinduction promotion and controlled biodegradability, configurating what is currently considered as a possible gold standard material for bone substitution in reconstructive surgery. Exploring the natural genesis of the HAp and ß-TCP phases in fishbones during their postnatal growth, this study developed a biphasic bioceramic obtained from the calcination of Nile tilapia (Oreochromis niloticus) bones as a function of their ages. The natural genesis dynamics of the structural evolution of the ß-TCP and HAp phases were characterized by physicochemical methods, taking into account of the age of the fish and the material processing conditions. Thermal analysis (TGA / DTA) showed complete removal of the organic matter and transitions associated with the transformation of carbonated hydroxyapatite (CDHA) to HAp and ß-TCP phases. After calcination at 900 °C, the material was characterized by: X-ray diffraction (XRD) and refinement by the Rietveld method; Fourier Transform Infrared Spectroscopy with Attenuated Total Reflection (FTIR-ATR); Raman spectroscopy; Scanning Electron Microscopy (SEM) and Flame Atomic Absorption Spectroscopy (FAAS). The analysis allowed identification and quantitative estimate of the variations of the HAp and ß-TCP phases in the formation of the BCPs. The results showed that the decrease in ß-TCP against the increase in the HAp phases is symmetrical to the dynamics of the natural genesis of these phases, surprisingly maintaining the balanced phase proportion even when bones of young fishes were used. The microstructure analysis confirms the observed transformation. In addition, in vivo tests demonstrated the osteoinductive potential of BCP scaffolds implanted in an ectopic site, and their remarkable regenerative functionality, as bone graft, was demonstrated in alveolar bone after tooth extraction. MTT cytotoxicity assay for BCP samples for MC3T3-E1 pre-osteoblasts and L929 fibroblasts cells showed viability equal or higher than 100%. A logistic empirical model is presented to explain the three stages of HAp natural formation with fish age and it is also compared to the fish size evolution.

Immune response and Raman scattering assessment in rats skin after contact with Fusarium oxysporum metabolites.

The secondary metabolites produced by Fusarium can cause disease and death when consumed and produce biological responses even in the absence of the microorganism. The IL-6, TNF-α and TGF-ß1 cytokines immune reactivity was associated with histopathological and physico-chemical changes in skin of immune competent rats after administration of Fusarium oxysporum crude extract. Rats were intradermally injected with 50 µl of 0.5 mg/ml crude extract and were euthanized at 3, 6, 12 and 24 h after injection. The inflammatory response was quantified by enzyme myeloperoxidase activity and by immunohistochemical method to detect the IL-6, TNF-α and TGF-ß1. Physico-chemical analysis was performed using FT-Raman Spectroscopy. The inflammatory response was most intense at 6 and 12 h after crude extract administration and the most significant histopathological changes were observed in the dermis. Myeloperoxidase activity was intense from 3 to 24 h after injection. The immunostaining of pro-inflammatory cytokines IL-6 and TNF-α peaked at 6 h. Immunostaining for TGF-ß1 was highest at 12 and 24 h. FT-Raman spectral analysis showed both, the most intense Fusarium interaction with the skin at 6 h, as revealed by the changes in the stretching of -CH bands (3100-2800 cm-1) in the dermis, and skin recovery trending after 12 h after crude extract injection. The results showed that secondary metabolites stimulated histopathologic changes and inflammatory responses even in the absence of the fungus, increasing myeloperoxidase activity and pro-inflammatory cytokine expression besides promoting physico-chemical changes.

Cell wall structure and composition is affected by light quality in tomato seedlings.

Light affects many aspects of cell development. Tomato seedlings growing at different light qualities (white, blue, green, red, far-red) and in the dark displayed alterations in cell wall structure and composition. A strong and negative correlation was found between cell wall thickness and hypocotyl growth. Cell walls was thicker under blue and white lights and thinner under far-red light and in the dark, while intermediate values was observed for red or green lights. Additionally, the inside layer surface of cell wall presented random deposited microfibrillae angles under far-red light and in the dark. However, longitudinal transmission electron microscopy indicates a high frequency of microfibrils close to parallels related to the elongation axis in the outer layer. This was confirmed by ultra-high resolution small angle X-ray scattering. These data suggest that cellulose microfibrils would be passively reoriented in the longitudinal direction. As the cell expands, the most recently deposited layers (inside) behave differentially oriented compared to older (outer) layers in the dark or under FR lights, agreeing with the multinet growth hypothesis. High Ca and pectin levels were found in the cell wall of seedlings growing under blue and white light, also contributing to the low extensibility of the cell wall. Low Ca and pectin contents were found in the dark and under far-red light. Auxins marginally stimulated growth in thin cell wall circumstances. Hypocotyl growth was stimulated by gibberellins under blue light.