Recovery of bioactive compounds from an agro-industrial waste: extraction, microencapsulation, and characterization of jaboticaba(Myrciaria cauliflora Berg) pomace as a source of antioxidant.

This study aimed to evaluate the extraction of bioactive compounds from jaboticaba pomace, produce microcapsules by spray dryer technique, and characterize antioxidant compounds. A factorial experimental design was used in the extraction step. Maltodextrin (DE 10) was used as an encapsulating agent, in a ratio of 1: 1 (w/w), in the microencapsulation process. It was observed the increase of all bioactive compounds analyses comparing jaboticaba pomace with the extract. ATR-FTIR spectroscopy showed a vibrational stretching aromatic ring (1718 - 1731 cm-1) typical for anthocyanins. The Gaussian deconvolution presented extract peak area 7.56% higher than pomace. The encapsulating agent protected anthocyanins during the drying process. Microencapsulation of bioactive compounds from jaboticaba pomace can be useful for food applications whereas they are a rich source of antioxidant compounds. Moreover, the use of agro-industrial waste is promising linked to the use of clean technology as water as an antioxidant extractor.

Opalescence and color stability of composite resins: an in vitro longitudinal study.

OBJECTIVES: This study aims to evaluate the opalescence (OP) and color stability of composite resins over a period of 180 days and to compare composite resins' OP with enamel's OP. MATERIALS AND METHODS: Twenty human enamel specimens (5.0 × 0.3 mm) and 9 specimens (10.0 × 1.0 mm) of 10 colors of 4 different composite resins (3 M ESPE, FGM, Ivoclar-Vivadent, Miscerium) and one brand of adhesive (3 M ESPE) were made. The results were obtained by measuring the reflectance and transmittance spectra in the visible region. After baseline measurement, composites and adhesive were analyzed after 2, 7, 30, 60, 120, and 180 days. The Lab color coordinates were used in the calculations of the OP parameter and color differences in the CIELab and CIEDE2000 methods. The data were analyzed statistically. RESULTS: The materials tested showed variation and an increase in OP over time. The OP found for enamel was 18.06 ± 2.99, and some resins showed higher results. There was a strong correlation between the coordinate b*T and the OP over time. Enamel Plus was the only one material that presented no color changes during all periods in both color analyses. Filtek Z350 XT, AT, and BT did not show differences in any time when analyzed by CIELAB. CONCLUSIONS: The OP of most composite resins changed during the period of 180 days and was different from the OP of tooth enamel. In general, composites demonstrated small color changes over the period tested, being this characteristic material dependent. CLINICAL RELEVANCE: Natural teeth present different optical properties. Composite resins restorations should present properties similar to natural teeth and it is important that characteristics like color and opalescence remain stable over time.

Brewing by-product valorisation: trub debittered for nutritional and quality improvement of pasta.

Trub, a brewing by-product, can be used as alternative ingredient for foods nutritional enrichment after its bitter compounds extraction. Study presents the optimisation of bitter compounds extraction from trub by Box-Behnken design, and use of debittered trub (DT) as new ingredient to enrich pasta. Bitterness extraction process was evaluated at different pH levels, time and extraction steps, and physical-chemical properties of DT (obtained under optimal conditions) were evaluated. Pasta was enriched with DT (5%, 10% and 15%) and its physical-chemical and quality properties were evaluated. Protein structure and chemical composition of trub were altered after process, also modifying its technological properties. Pasta with 10% DT increased in 33.51% protein content. Interaction of DT and wheat proteins resulted in a more compact structure, and DT water absorption capacity provided pasta texture changes. DT use improved pasta nutritional and quality properties, enabling trub valorisation and its use as vegetable proteins alternative source.

Thermoresponsive Hydrogel-Loading Aluminum Chloride Phthalocyanine as a Drug Release Platform for Topical Administration in Photodynamic Therapy.

Phthalocyanine aluminum chloride (Pc) is a clinically viable photosensitizer (PS) to treat skin lesions worsened by microbial infections. However, this molecule presents a high self-aggregation tendency in the biological fluid, which is an in vivo direct administration obstacle. This study proposed the use of bioadhesive and thermoresponsive hydrogels comprising triblock-type Pluronic F127 and Carbopol 934P (FCarb) as drug delivery platforms of Pc (FCarbPc)-targeting topical administration. Carbopol 934P was used to increase the F127 hydrogel adhesion on the skin. Rheological analyses showed that the Pc presented a low effect on the hydrogel matrix, changing the gelation temperature from 27.2 ± 0.1 to 28.5 ± 0.9 °C once the Pc concentration increases from zero to 1 mmol L-1. The dermatological platform showed matrix erosion effects with the release of loaded Pc micelles. The permeation studies showed the excellent potential of the FCarb platform, which allowed the partition of the PS into deeper layers of the skin. The applicability of this dermatological platform in photodynamic therapy was evaluated by the generation of reactive species which was demonstrated by chemical photodynamic efficiency assays. The low effect on cell viability and proliferation in the dark was demonstrated by in vitro assays using L929 fibroblasts. The FCarbPc fostered the inhibition of Staphylococcus aureus strain, therefore demonstrating the platform's potential in the treatment of dermatological infections of microbial nature.

Translucency parameter of conventional restorative glass-ionomer cements.

OBJECTIVE: To evaluate the translucency parameter (TP) and contrast ratio (CR) of different conventional restorative glass-ionomer cements (GICs). MATERIALS AND METHODS: Eighteen brands of GICs were evaluated. Five disks of each material were made following ISO 9917-1. The luminous reflectance and Central Bureau of the International Commission on Illumination parameters of disks were evaluated using a colorimeter, against backings of white and black, to obtain the translucent parameter and contrast ratio of different brands of glass-ionomer cements. The correlation between translucency parameter and contrast ratio was assessed with the Pearson correlation test. The translucent and contrast ratio parameters values were submitted to the one-way ANOVA and Tukey test for multiple comparisons (p < 0.05). RESULTS: There was a strong inverse relationship between CR and TP (r2  = 0.94, p < 0.001). The contrast ratio decreased as translucency increased. There were significant differences in TP and CR among brands (p < 0.001). CONLUSIONS: GICs exhibit different translucency and contrast ratio behavior. Some brands of GICs presented very low TP and this condition would be unacceptable for areas with esthetic demands. In addition, TP and CR showed a strong linear relationship. CLINICAL SIGNIFICANCE: The results found in this study demonstrated that the knowledge of the translucency and CR of different conventional restorative GICs is important in order to guide clinicians in the selection of restorative GICs for anterior teeth.

Human Nails Permeation of an Antifungal Candidate Hydroalcoholic Extract from the Plant Sapindus saponaria L. Rich in Saponins.

We evaluated a hydroalcoholic extract of Sapindus saponaria L. pericarps (ETHOSS), as a candidate to a topical antifungal medicine for onychomycosis. ETHOSS was produced by extracting the crushed fruits in ethanol. The saponin contents were identified and characterized by electrospray ionization mass spectrometry. We measured the in vitro antifungal activity against three dermatophyte fungi, isolated from onychomycosis: Trichophyton rubrum, T. mentagrophytes, and T. interdigitale, using broth microdilution tests. The minimum fungicide concentration of ETHOSS ranged from 195.31 to 781.25 µg/mL. The cytotoxicity of the crude extract was tested on the HeLa cell line, and its ability to permeate into healthy human nails by photoacoustic spectroscopy and Fourier transformation infrared spectrometer (FTIR) spectroscopy by attenuated total reflection. Besides its strong antifungal activity, ETHOSS showed low cytotoxicity in human cells. It was able to permeate and reach the full thickness of the nail in one hour, without the aid of facilitating vehicles, and remained there for at least 24 h. These results suggest that ETHOSS has great potential for treating onychomycosis.

Hesperidin-Loaded Solid Lipid Nanoparticles: Development and Physicochemical Properties Evaluation.

Although nanocarrier systems have been investigated to function as therapeutic delivery agents to specific sites of the body, the drug encapsulation method is not always well elucidated. In this work, solid lipid nanoparticles (SLN) composed by stearic acid or cetostearyl alcohol were prepared by a hot homogenization method using poly(vinyl alcohol) or polysorbate as surfactant and loaded with hesperidin, a bioflavonoid that possesses many pharmacological properties. The obtained SLN were characterized by several physicochemical techniques to identify interactions between the constituents and to evaluate the drug incorporation into the nanoparticles. According to scanning electron microscopy and dynamic light scattering the hesperidin-loaded and unloaded SLN have spherical shapes, sizes ranging from 300 to 600 nm, zeta potentials varying from -35 to -20 mV, polydispersity indexes between 0.240 and 0.445, and entrapment efficiencies higher than 88%. X-ray diffraction showed the hesperidin amorphization due to its encapsulation in SLN, and also showed crystallization degree and polymorphic modification of the lipids after the SLN preparation. FTIR, Raman and Photoacoustic spectroscopy revealed no chemical reactions between drug and lipids, however, these results indicated that the drug was incorporated differently into nanoparticles based on the SLN composition. The analysis showed that stearic acid-based SLN prepared with polysorbate were more efficient to enclosure the hesperidin while the glycosydic part of the hesperidin was not entrapped in the cetostearyl alcohol-based SLN; instead, the hesperidin remained on the SLN surface due to lipid crystallization. The physicochemical characterization allowed identifying different types of hesperidin incorporation into the SLN, which can interact in a varied manner as targeted drug delivery systems.

Biomedical Platform Development of a Chlorophyll-Based Extract for Topic Photodynamic Therapy: Mechanical and Spectroscopic Properties.

Photodynamic therapy (PDT) is a therapeutic modality that has shown effectiveness in the inactivation of cancer cell lines and microorganisms. Treatment consists of activating the photosensitizer (PS) upon light irradiation of adequate wavelength. After reaching the excited state, the PS can handle the intersystem conversion through energy transfer to the molecular oxygen, generating reactive oxygen species. This especially applies to singlet oxygen (1O2), which is responsible for the selective destruction of the sick tissue. Photosensitizing compounds (chlorophylls and derivatives) existing in the spinach extract have applicability for PDT. This study aimed to develop and characterize the thermoresponsive bioadhesive system composed of Pluronic F127 20.0%- and Carbopol 934P 0.2% (w/w) (FC)-containing chlorophyll-based extract 0.5% (w/w) (FC-Chl). Mechanical and rheological properties, in vitro release, sol-gel transition temperature, and ex vivo permeability of the spinach extract PS components (through pig ear skin) were investigated. Furthermore, photodynamic activity of the system was accessed through uric acid and time-solved measurements. The sol-gel transition temperature obtained for the FC-Chl system was 28.8 ± 0.3 °C. Rheological and texture properties of the platform were suitable for use as a dermatological system, exhibiting easy application and good characteristics of retention in the place of administration. In vitro release studies showed the presence of two distinct mechanisms that reasonably obey the zero-order and first-order kinetics models. PS components presented skin permeability and reached a permeation depth of 830 µm (between the epidermis and dermis). The photodynamic evaluation of the FC-Chl system was effective in the degradation of uric acid. The quantum yield (ΦΔ1O2) and life time (τ1O2) of singlet oxygen showed similar values for the spinach extract and the isolated chlorophyll a species in ethanol. These results allowed for the classification of the FC-Chl platform as potentially useful for the delivery of the chlorophyll-based extract in the topic PDT, suggesting that it is worthy for in vivo evaluation.

Influence of immediate dentin sealing and interim cementation on the adhesion of indirect restorations with dual-polymerizing resin cement.

STATEMENT OF PROBLEM: Dentin surface contamination before the cementation of indirect restorations may impact bonding effectiveness. PURPOSE: The purpose of this in vitro study was to analyze the influence of immediate dentin sealing (IDS) and interim cementation on the adhesion of indirect restorations with a dual-polymerizing resin cement. MATERIAL AND METHODS: Composite resin inlays were placed in class V cavities prepared in the buccal and lingual surfaces of 30 extracted human molars with a dual-polymerizing resin cement in 3 different ways (n=10): CG, directly on dentin; PG, after 14 days interim cementation; SG, after IDS and 14 days interim cementation. Buccal restorations were sectioned into sticks and submitted to the microtensile bond strength (µTBS) test. Lingual restorations were submitted to micro-Raman spectroscopy (MRS). Data were analyzed with 1-way ANOVA and the Tukey-Kramer post hoc test (α=.05). RESULTS: Significantly higher µTBS results were found for SG (35.7 ±8.2 MPa) when compared with CG (23.1 ±7.1 MPa) and PG (17.0 ±6.0 MPa) (P<.05), but no differences were observed between CG and PG. MRS showed that the diffusion zone in SG (3.7 ±0.5 µm) was significantly thicker than that of CG (1.8 ±1.2 µm) or PG (1.5 ±0.3 µm) (P<.05). Additionally, a new interface peak (at approximately 1330 cm-1) was found in SG, indicating a chemical interaction. CONCLUSIONS: The use of IDS before cementation resulted in a chemical interaction at the interface and significantly higher µTBS and diffusion zone thickness values. Interim cementation did not interfere with adhesion quality when compared with the control group.

Time-resolved fluctuation during the photochemical reaction of a photoreceptor protein: phototropin1LOV2-linker.

Although the relationship between structural fluctuations and reactions is important for elucidating reaction mechanisms, experimental data describing such fluctuations of reaction intermediates are sparse. In order to investigate structural fluctuations during a protein reaction, the compressibilities of intermediate species after photoexcitation of a phot1LOV2-linker, which is a typical LOV domain protein with the C-terminal linker including the J-α helix and used recently for optogenetics, were measured in the time-domain by the transient grating and transient lens methods with a high pressure optical cell. The yield of covalent bond formation between the chromophore and a Cys residue (S state formation) relative to that at 0.1 MPa decreased very slightly with increasing pressure. The fraction of the reactive species that yields the T state (linker-unfolded state) decreased almost proportionally with pressure (0.1-200 MPa) to about 65%. Interestingly, the volume change associated with the reaction was much more pressure sensitive. By combining these data, the compressibility changes for the short lived intermediate (S state) and the final product (T state) formation were determined. The compressibility of the S state was found to increase compared with the dark (D) state, and the compressibility decreased during the transition from the S state to the T state. The compressibility change is discussed in terms of cavities inside the protein. By comparing the crystal structures of the phot1LOV2-linker at dark and light states, we concluded that the cavity volumes between the LOV domain and the linker domain increase in the S state, which explains the enhanced compressibility.

Color stability over time of three resin-based restorative materials stored dry and in artificial saliva.

OBJECTIVE: To evaluate the color match of different composite resins relative to Vitapan Classical shade guide tab and their respective manufacturers' shade guide tabs as a function of time and storage. MATERIALS AND METHODS: Three enamel shade A2 composite resins were used to fabricate 36 disk-shaped polymerized specimens (12 each), allocated into 2 groups of 6 and stored dry (GD) and in artificial saliva (GS). CIELAB coordinates from shade tabs and resin specimens immediately after polymerization (t0), and 24 hours (t1), 7 (t7), 14 (t14) and 21 (t21) days after polymerization were captured using a colorimeter. Color difference (ΔE00 ) between composite specimens and the reference tabs was calculated using the CIEDE2000 formula. The results were analyzed with repeated measures ANOVA, Tukey's HDS post-hoc test, and Student t test (p ≤ 0.05). RESULTS: Color of the three tested composites relative to Vita and their respective tabs significantly changed as a function of time until t14; however, between t14 and t21, no significant differences were found. No differences in color were found relative to storage at t14 and t21. ΔE00 values of specimens at t14 were significantly higher relative to their respective tabs than to Vitapan tab. CONCLUSIONS: For all brands color changed up to day 14, when it stabilized, regardless of whether composite specimens had been stored in artificial saliva or simply in a box. Vitapan tab presented a better color match than the manufacturers' tabs. CLINICAL SIGNIFICANCE: The results found in this study demonstrated that the Vitapan Classical shade guide tab A2 provided a better color match than the respective shade guide tabs A2 supplied by the composite manufacturers. If custom shade tabs are to be made, however, they could be kept in a box and used as shade references from 14 days after being fabricated, when color stabilizes.

Optimization and Characterization of Protein Extraction from Asparagus Leafy By-Products.

Asparagus production generates significant amounts of by-products during the summer and post-harvest growth period. By-products can be good sources of nutrients and phytochemicals. The interest in increasing the availability of proteins for human consumption has led to the use of new plant sources rich in proteins. The objective of this study was to use response surface methodology (RSM) to optimize the aqueous extraction process of proteins from asparagus leafy by-products, for the production of new protein ingredients. The optimum extraction condition was at pH 9, with 40 min of extraction at 50 °C, and the concentration was fixed at 5 g·L-1. The isolate obtained presented 90.48% protein with 43.47% protein yield. Amino acids such as alanine, proline, valine, leucine/isoleucine, asparagine, and phenylalanine were identified, and the antioxidant activity for 2,2 AZINO BIS (3-ethylbenzo thiazoline 6 sulfonic acid diammonium salt) was 145.76 equivalent to Trolox µmol.100g-1 and for DPPH 65.21 equivalent to Trolox µmol.100g-1. The product presented favorable technological properties (water absorption capacity 4.49 g·g-1 and oil absorption capacity 3.47 g·g-1) and the color tended towards dark green (L* 31.91, a* -1.01, b* -2.11). The protein isolate obtained through the extraction optimization process showed high potential to be used as a protein ingredient.

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.

Characterization of a biofilm formed by Fusarium oxysporum on the human nails.

BACKGROUND: Fusarium spp. has been considered as an onychomycosis agent, but little is known about the etiopathogenesis of fusarial onychomycosis; thus, the objective of this study was to characterize the fungal-nail interaction and the consequences of the nail infection process by Fusarium oxysporum using the human nail, in an ex vivo model. METHODS: The kinetic of biofilm production and infection by F. oxysporum using the nail as the only nutritional source were evaluated by scanning electron microscopy, number of culturable cells, metabolic activity, characterization of extracellular matrix, spectroscopy and histopathology analyses. RESULTS: After evaluating the biofilm kinetic over 7 days using different parameters and techniques, it was possible to characterize the Fusarium-nail interaction. CONCLUSIONS: This study is a part of a big project aiming to clarify the fusarial pathogenesis and contributes to proving F. oxysporum is able to adapt, grow, develop, and form a biofilm on healthy human nails, which are crucial steps for the invasion process.

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.

Technique for Darkening of Extracted Teeth Simulating Pulpal Necrosis Discoloration.

Background: The use of discolored teeth is required to test whitening products, and it is difficult to obtain them, given their scarcity. Objective: To present a technique for in vitro darkening of extracted teeth simulating pulpal necrosis discoloration. Materials and Methods: Hemolysates I and II from human blood were subjected or not to laser irradiation (442 nm) for 1 h. The concentration of oxyhemoglobin (O2Hb) was analyzed by ultraviolet/visible spectroscopy, and the conversion of O2Hb to methemoglobin (MetHb) by transmission spectroscopy was assessed immediately and after 3 and 40 days. For darkening evaluation, bovine incisors were divided into two groups (n = 25), and their pulp chambers were filled with hemolysate solution II (HSII) and hemolysate II solution + laser (HSII+L). After storage in artificial saliva for 40 days at 37°C, color changes were measured by a colorimeter and ΔE was compared with the NBS parameters. Data were analyzed using a mixed linear model (α=5%). Results: HSII+L presented the lowest O2Hb and higher MetHb. The conversion of O2Hb to MetHb in HSII+L was 42% higher than in HSII. Both groups were effective in darkening the teeth, according to the NBS. Darkening stabilized from day 35. HSII promoted a marked color difference. Conclusion: The proposed technique was effective in darkening the extracted teeth simulating necrosis discoloration for in vitro models.

Bioperformance Studies of Biphasic Calcium Phosphate Scaffolds Extracted from Fish Bones Impregnated with Free Curcumin and Complexed with ß-Cyclodextrin in Bone Regeneration.

Fish bones are a natural calcium phosphate (CaP) sources used in biomaterials production for bone regeneration. CaP scaffolds can be enriched with other substances with biological activity to improve bone repair. This study aimed to evaluate the physicochemical properties and bone regeneration potential of biphasic calcium phosphate (BCP) scaffolds impregnated with free curcumin (BCP-CL) or complexed with ß-cyclodextrin (BCP-CD) compared to BCP scaffolds. Rietveld's refinement showed that BCP is composed of 57.2% of HAp and 42.8% of ß-TCP and the molar ratio of Ca/P corresponds to 1.59. The scaffolds presented porosity (macro and microporosity) of 57.21%. Apatite formation occurred on the BCP, BCP-CL, and BCP-CD surface, in vitro, in SBF. Micro-Raman technique showed a reduction in the dissolution rate of ß-TCP in the curcumin-impregnated scaffolds over time, and in vivo studies on critical-size defects, in rat calvaria, had no additional regenerative effect of BCP-CL and BCP-CD scaffolds, compared to BCP scaffolds. Despite this, the study showed that curcumin impregnation in BCP scaffolds prolongs the release of the ß-TCP phase, the BCP- phase with the higher osteoinductive potential, representing an advantage in tissue engineering.

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.