Francielle Sato

Curcumin–β-cyclodextrin inclusion complex: Stability, solubility, characterisation by FT-IR, FT-Raman, X-ray diffraction and photoacoustic spectroscopy, and food application

Curcumin was complexed with β-CD using co-precipitation, freeze-drying and solvent evaporation methods. Co-precipitation enabled complex formation, as indicated by the FT-IR and FT-Raman techniques via the shifts in the peaks that were assigned to the aromatic rings of curcumin. In addition, photoacoustic spectroscopy and X-ray diffraction, with the disappearance of the band related to aromatic rings, by Gaussian fitting, and modifications in the spectral lines, respectively, also suggested complex formation. The possible complexation had an efficiency of 74% and increased the solubility of the pure colourant 31-fold. Curcumin-β-CD complex exhibited a sunlight stability 18% higher than the pure colourant. This material was stable to pH variations and storage at -15 and 4°C. With an isothermal heating at 100 and 150°C for 2h, the material exhibited a colour retention of approximately 99%. The application of curcumin-β-CD complex in vanilla ice creams intensified the colour of the products and produced a great sensorial acceptance.

Hydrogen Peroxide Diffusion Dynamics in Dental Tissues

The aim of this study was to investigate the diffusion dynamics of 25% hydrogen peroxide (H2O2) through enamel-dentin layers and to correlate it with dentin’s structural alterations. Micro-Raman Spectroscopy (MRS) and Fourier Transform Infrared Photoacoustic Spectroscopy (FTIR-PAS) were used to measure the spectra of specimens before and during the bleaching procedure. H2O2 was applied to the outer surface of human enamel specimens for 60 minutes. MRS measurements were performed on the inner surface of enamel or on the subsurface dentin. In addition, H2O2 diffusion dynamics from outer enamel to dentin, passing through the dentin-enamel junction (DEJ) was obtained with Raman transverse scans. FTIR-PAS spectra were collected on the outer dentin. MRS findings revealed that H2O2 (O-O stretching µ-Raman band) crossed enamel, had a more marked concentration at DEJ, and accumulated in dentin. FTIR-PAS analysis showed that H2O2 modified dentin’s organic compounds, observed by the decrease in amides I, II, and III absorption band intensities. In conclusion, H2O2 penetration was demonstrated to be not merely a physical passage through enamel interprismatic spaces into the dentinal tubules. H2O2 diffusion dynamics presented a concentration gradient determined by the chemical affinity of the H2O2 with each specific dental tissue.

Morphological and Structural Changes in Lung Tissue Infected by Paracoccidioides brasiliensis: FTIR Photoacoustic Spectroscopy and Histological Analysis

This study evaluated physical, chemical and morphological changes in lungs of mice infected with Paracoccidioides brasiliensis. The animals were inoculated with 0.1 mL of fungal suspension of the P. brasiliensis 18 isolate and were euthanized 1, 2, 4 and 8 weeks after inoculation. The upper left lobe of the lung was isolated, fixed and processed for paraffin embedding. The sections were stained with H&E for histopathological study, with Gomori‐Grocott to locate and identify the fungus, and with TUNEL immunostaining to detect the occurrence of programmed cell death. The lower and middle right lobes were analyzed by Fourier Transform Infrared Photoacoustic Spectrocopy (FTIR‐PAS) to investigate physical and chemical features of the infected lungs. The results showed that lungs infected by P. brasiliensis underwent structural changes that varied according to the time period analyzed, and that changes in the absorption bands of different chemical groups resulted from these morphological changes. The results suggest that the combination of FTIR‐PAS spectroscopy with morphological evaluation is an effective procedure for the study of paracoccidioidomycosis, one of the most important systemic mycoses that can damage the lung architecture and consequently impair the respiratory function.

Singlet oxygen production by combining erythrosine and halogen light for photodynamic inactivation of Streptococcus mutans

BACKGROUND Photodynamic inactivation of microorganisms is based on a photosensitizing substance which, in the presence of light and molecular oxygen, produces singlet oxygen, a toxic agent to microorganisms and tumor cells. This study aimed to evaluate singlet oxygen quantum yield of erythrosine solutions illuminated with a halogen light source in comparison to a LED array (control), and the photodynamic effect of erythrosine dye in association with the halogen light source on Streptococcus mutans. METHODS Singlet oxygen quantum yield of erythrosine solutions was quantified using uric acid as a chemical-probe in an aqueous solution. The in vitro effect of the photodynamic antimicrobial activity of erythrosine in association with the halogen photopolimerizing light on Streptococcus mutans (UA 159) was assessed during one minute. Bacterial cultures treated with erythrosine alone served as negative control. RESULTS Singlet oxygen with 24% and 2.8% degradation of uric acid in one minute and a quantum yield of 0.59 and 0.63 was obtained for the erythrosine samples illuminated with the halogen light and the LED array, respectively. The bacterial cultures with erythrosine illuminated with the halogen light presented a decreased number of CFU mL(-1) in comparison with the negative control, with minimal inhibitory concentrations between 0.312 and 0.156mgmL(-1). CONCLUSIONS The photodynamic response of erythrosine induced by the halogen light was capable of killing S. mutans. Clinical trials should be conducted to better ascertain the use of erythrosine in association with halogen light source for the treatment of dental caries.

Insulin complexation with hydroxypropyl-beta-cyclodextrin: Spectroscopic evaluation of molecular inclusion and use of the complex in gel for healing of pressure ulcers.

The pressure ulcer healing is a complex process and difficult to be achieved. Insulin is known to promote wound healing, and when complexed with cyclodextrin presents improved solubility, stability and biological activity. Complexation of insulin with hydroxypropyl-beta-cyclodextrin (HPβCD) was performed in this work through the coprecipitation method, providing the inclusion complex (HPβCD-I). The spectroscopic techniques used to analyze the complex were H(1) NMR, FT-Raman and FT-IR/ATR. A gel containing the HPβCD-I complex was prepared and a clinical study was conducted in patients with pressure ulcers. The spectroscopic techniques allowed to confirm the complex formation through the inclusion of aromatic amino acids, such as phenylalanine present in the HPβCD cavity. Data obtained from the FT-Raman and FT-IR/ATR techniques, combined with the H(1) NMR results, showed the effectiveness of these techniques in evaluating the inclusion complex of HPβCD with insulin. Clinical studies demonstrated tissue revitalization and a trend (p=0.06) for a significant difference between the healing effect of the control gel and that with HPβCD-I complex. The creation of the gel prepared with insulin and HPβCD-I complex and its use in patients with pressure ulcers appears to be promising in wound healing and its possible use in hospital care.

Fourier transform infrared photoacoustic spectroscopy study of physicochemical interaction between human dentin and etch-&-rinse adhesives in a simulated moist bond technique

The purpose of this study was to provide the physicochemical interactions at the interfaces between two commercial etch-&-rinse adhesives and human dentin in a simulated moist bond technique. Six dentin specimens were divided into two groups (n=3) according to the use of two different adhesive systems: (a) 2-hydroxyethylmethacrylate (HEMA) and 4-methacryloxyethyl trimellitate anhydrate (4-META), and (b) HEMA. The Fourier transform infrared photoacoustic spectroscopy was performed before and after dentin treatment with 37% phosphoric acid, with adhesive systems and also for the adhesive systems alone. Acid-conditioning resulted in a decalcification pattern. Adhesive treated spectra subtraction suggested the occurrence of chemical bonding to dentin expressed through modifications of the OH stretching peak (3340 cm(-1)) and symmetric CH stretching (2900 cm(-1)) for both adhesives spectra; a decrease of orthophosphate absorption band (1040 to 970 cm(-1)) for adhesive A and a better resolved complex band formation (1270 to 970 cm(-1)) for adhesive B were observed. These results suggested the occurrence of chemical bonding between sound human dentin and etch-&-rinse adhesives through a clinical typical condition.

Evaluation of photosensitizer penetration into sound and decayed dentin: A photoacoustic spectroscopy study

BACKGROUND Photodynamic therapy (PDT) may have topical indications. In those cases it is important for a topical photosensitizer to penetrate into the tissue to which it has been applied. This study aimed to compare the penetration of two different concentrations of erythrosine into intact and in vitro decayed dentin samples. METHODS This in vitro study evaluated erythrosine (0.3 and 5%) penetration into sound (intact) and decayed dentin. A total of 11 dentin discs were prepared and divided into two equal halves, in order to keep one half sound while the other half was submitted to sterilization and an in vitro demineralization model for 5 days. Before erythrosine application, the organic and inorganic composition of all samples was evaluated by Fourier Transform Raman spectroscopy, and after erythrosine application for 30 min, the penetration depth was determined by Photoacoustic spectroscopy technique. RESULTS The results indicated that 0.3% erythrosine showed a higher penetration depth into sound dentin (p = 0.002); and 5% erythrosine higher penetration into decayed dentin (p < 0.001). However considering clinical parameters, no statistically significant difference was found between any of the conditions tested. CONCLUSIONS Erythrosine demonstrated ability to penetrate into dentin, irrespective of sound or decayed condition. Photoacoustic spectroscopy can be considered a method for estimating the penetration into hard tissues, and in conjunction with Raman spectroscopy, these are effective methods for evaluating the spectral response of dentin. Considering that erythrosine is capable of penetrating into decayed dentin, clinical trials are needed to test the effectiveness of this photosensitizer in Photodynamic therapy and Antimicrobial Photodynamic therapy.

Crude extract of Fusarium oxysporum induces apoptosis and structural alterations in the skin of healthy rats

Abstract. We evaluate the biological and physicochemical effects of a Fusarium oxysporum crude extract (CE) on the skin of healthy rats. The CE is topically applied and subsequently the skin is collected after 3, 6, 12, and 24 h. The samples are analyzed by Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) and histomorphometric analysis. Terminal dUTP nick end labeling (TUNEL assay) is performed to detect both the cells in apoptosis and proliferation. There is a thickening of the epidermis after 6, 12, and 24 h and dermis after 12 and 24 h of CE application. A reduction of the dermis thickness is observed at 3 and 6 h. The treated skin shows higher labeling intensity by TUNEL at 3 h, while a higher intensity by proliferating cell nuclear antigen occurs at 3 and 12 h. FTIR-PAS data support the histology observations showing an increase in the absorption peaks in the dermis after the application of the CE. F. oxysporum CE permeated through the epidermis and the dermis, reaching the subcutaneous tissue, inducing cell apoptosis, and causing physicochemical changes in the organic molecules located in the dermis. This is the first known study associating histopathological and physical chemistry changes on healthy skin after the application of F. oxysporum CE.

Evidence of anti-inflammatory effect and percutaneous penetration of a topically applied fish oil preparation: a photoacoustic spectroscopy study

Abstract. This paper investigates the topical anti-inflammatory effect of a fish oil preparation (FOP) in a croton oil (CO) model of skin inflammation. The photoacoustic spectroscopy (PAS) was applied to estimate the percutaneous penetration of the FOP and as a model to evaluate the topical inflammatory response. After applying CO, the groups of mice received a topical application of a FOP on the left ear. The right ear received the vehicle that was used to dilute the CO. After 6 h, ear tissue was collected to determine the percent inhibition of edema, myeloperoxidase (MPO) activity, and cytokine levels and to perform PAS measurements. Treatment with FOP reduced edema and MPO activity, which was at least partially attributed to a decrease in the levels of tumor necrosis factor, interleukin-1β, interleukin-6, keratinocyte-derived chemokine, and monocyte chemoattractant protein-1. The topically applied FOP penetrated into the tissue and decreased the area of the bands that characterize inflamed tissue. The present results demonstrated the topical anti-inflammatory effect of the FOP. PAS suggests that FOP anti-inflammatory activity is linked with its ability to penetrate through the skin.

Correlation between Histopathological and FT-Raman Spectroscopy Analysis of the Liver of Swiss Mice Infected with Paracoccidioides brasiliensis

Paracoccidioidomycosis is the most important systemic mycosis in Latin America. The main entrance of the fungus is the airway. It primarily occurs in the lung, but in its disseminated form may affect any organ. The liver is one of the organs afflicted by this disease and its homeostasis may be impaired. The aim of the present study was to evaluate the evolution of paracoccidioidomycosis in the liver of Swiss mice and correlate morphological factors with the expression of gp43 and with physicochemical analysis via FT-Raman of the infected organ. According to colony forming unit (CFU) and granuloma counting, the first and second weeks were the periods when infection was most severe. Tissue response was characterized by the development of organized granulomas and widespread infection, with yeasts located within the macrophages and isolated hepatocytes. The gp43 molecule was distributed throughout the hepatic parenchyma, and immunostaining was constant in all observed periods. The main physicochemical changes of the infected liver were observed in the spectral ranges between 1700–1530 cm−1 and 1370 – 1290 cm−1, a peak shifting center attributed to phenylalanine and area variation of -CH2 and -CH3 compounds associated to collagen, respectively. Over time, there was a direct proportional relationship between the number of CFUs, the number of granulomas and the physicochemical changes in the liver of mice infected with Paracoccidioides brasiliensis. The expression of gp43 was similar in all observed periods.