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Made available in DSpace on 2018-12-11T17:23:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-11-05 A strain isolated from Kombucha tea was isolated and used as an alternative bacterium for the biosynthesis of bacterial cellulose (BC). In this study, BC generated by this novel bacterium was compared to Gluconacetobacter xylinus biosynthesized BC. Kinetic studies reveal that Komagataeibacter rhaeticus was a viable bacterium to produce BC according to yield, thickness and water holding capacity data. Physicochemical properties of BC membranes were investigated by UV–vis and Fourier transform infrared spectroscopies (FTIR), thermogravimetrical analysis (TGA) and X-ray diffraction (XRD). Additionally, scanning electron microscopy (SEM) and atomic force microscopy (AFM) were also used for morphological characterization. Mechanical properties at nano and macroscale were studied employing PeakForce quantitative nanomechanical property mapping (QNM) and dynamic mechanical analyzer (DMA), respectively. Results confirmed that BC membrane biosynthesized by Komagataeibacter rhaeticus had similar physicochemical, morphological and mechanical properties than BC membrane produced by Gluconacetobacter xylinus and can be widely used for the same applications. Laboratório de Biopolimeros e Biomateriais (BIOPOLMAT) Centro Universitário de Araraquara, Araraquara Group ‘Materials + Technologieś (GMT) Department of Chemical and Environmental Engineering Engineering College of Gipuzkoa University of the Basque Country (UPV/EHU), Plaza Europa 1 Laboratório de Pesquisa Desenvolvimento & Inovação Apis Flora Ind. Coml. Ltda, Ribeirão Preto Institute of Chemistry-São Paulo StateUniversity-UNESP Institute of Chemistry-São Paulo StateUniversity-UNESP

Bacterial cellulose (BC) produced by some bacteria, among them Gluconacetobacter xylinum, which secrets an abundant 3D networks fibrils, represents an interesting emerging biocompatible nanomaterial. Since its discovery BC has shown tremendous potential in a wide range of biomedical applications, such as artificial skin, artificial blood vessels and microvessels, wound dressing, among others. BC can be easily manipulated to improve its properties and/or functionalities resulting in several BC based nanocomposites. As example BC/collagen, BC/gelatin, BC/Fibroin, BC/Chitosan, etc. Thus, the aim of this review is to discuss about the applicability in biomedicine by demonstrating a variety of forms of this biopolymer highlighting in detail some qualities of bacterial cellulose. Therefore, various biomedical applications ranging from implants and scaffolds, carriers for drug delivery, wound-dressing materials, etc. that were reported until date will be presented.

Made available in DSpace on 2018-12-11T17:27:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-06-05 Three different low molecular weight nematic liquid crystals (LCs) were used to impregnate bacterial cellulose (BC) film. This simple fabrication pathway allows to obtain highly transparent BC based films. The coating of BC film with different liquid crystals changed transmittance spectra in ultraviolet-visible region and allows to design UVC and UVB shielding materials. Atomic force microscopy results confirmed that liquid crystals coated BC films maintain highly interconnected three-dimensional network characteristic of BC film and simultaneously, transversal cross-section scanning electron microscopy images indicated penetration of liquid crystals through the three-dimensional network of BC nanofibers. Investigated BC films maintain nematic liquid crystal properties being switchable photoluminiscence as a function of temperature during repeatable heating/cooling cycles. Conductive response of the liquid crystal coated BC films was proved by tunneling atomic force microscopy measurement. Moreover, liquid crystal coated BC films maintain thermal stability and mechanical properties of the BC film. Designed thermoresponsive materials possessed interesting optical and conductive properties opening a novel simple pathway of fabrication liquid crystal coated BC films with tuneable properties. Group 'Materials + Technologies' (GMT) Department of Chemical and Environmental Engineering Polytechnic School University of the Basque Country (UPV/EHU), Plaza Europa 1 Laboratory of Photonic Materials Institute of Chemistry São Paulo State University - UNESP Laboratório de Química Medicinal e Medicina Regenerativa (QUIMMERA) Centro Universitário de Araraquara Laboratory of Photonic Materials Institute of Chemistry São Paulo State University - UNESP

Made available in DSpace on 2018-12-11T17:23:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-01-01 Nickel polyphosphate coacervates have been prepared through the coacervation process of sodium polyphosphate and Ni2+ chloride solutions by the addition of different solvents with low molecular weight. The great potential of nickel polyphosphate coacervates as a material precursor was demonstrated by preparation of nickel polyphosphate glass-ceramics. Structural and spectroscopic properties were analyzed by thermal analysis, X-ray powder diffraction, Raman spectroscopic and UV-VIS techniques. Raman spectra for the nickel polyphosphate coacervates and nickel polyphosphate coacervates glass-ceramics samples shows that the addition of solvents leads to a depolymerization of the polyphosphate chains, resulting in an increase of shorter chains species based on pyrophosphates. The identification and quantification of Ni2P4012, β-Ni2P2O7 and δ-Ni2P2O7 crystalline phases present in the nickel polyphosphate glass-ceramics were carried out by X-ray powder diffraction using the Rietveld method. Quantitative phase analyses of the three polymorph forms were also evaluated. Based on interpretation of reflectance spectroscopy and Rietveld refinement, Ni2+ ions may occupy distorted octahedral and tetrahedral sites. LAVIE Department of Chemistry Federal University of São Carlos-UFSCar, CP 676 Institute of Chemistry Universidade Estadual Paulista-Unesp, P. O. Box 355 Laboratório de Biopolímeros e Biomateriais (BioPolMat) Centro Universitário de Araraquara (UNIARA) Núcleo de Espectroscopia e Estrutura Molecular-NEEM Departamento de Química Instituto de Ciências Exatas Universidade Federal de Juiz de Fora-UFJF Institute of Chemistry Universidade Estadual Paulista-Unesp, P. O. Box 355

This work describes the synthesis of bilayer bacterial cellulose membranes (BCs) produced by Gluconacetobacter hansenii ATCC 23769 in culture media with different carbon sources (sugarcane molasses, syrup and fructose) as well as their retention capacity and sustained release of the antibacterial agent ceftriaxone. Scanning electronic microscopy analysis showed that BCs produced in all culture media exhibit a double layer and three-dimensional fiber network obtained in only one step. Elemental and thermogravimetric analyses, Fourier transform infrared spectroscopy and X-ray diffraction show that the BC membranes are composed of pure cellulose. In particular, the BC produced in sugarcane molasses medium presented a three-dimensional network structure of the bilayer with high-density fiber entangling, which was responsible for the largest holding capacity and sustained release of the antibiotic ceftriaxone in relation to Staphylococcus aureus bacterial strains. This behavior shows the potential of applying such BC membranes in wound dressings as a sustained support to release different antibiotics to treat skin infections.

The uses of polymer blends have stimulated research to promote a better performance of existing raw materials. The implementation of blends in the production of polymeric membranes has shown great results in regenerative medicine and consequently it has improved the application of biomaterials in this area. This study aimed to evaluate the morphology and wettability of a bacterial cellulose/corn starch polymeric membrane. In relation to biomaterials, wettability is an important property to be evaluated because it is possible to observe if the degradation is accelerated even when in contact with biological fluids. The membrane was morphologically evaluated by SEM. Results showed that there was interaction between the polymers. Additionally, by the technique of contact angle it was also possible to observe the ability to absorb water, being highly satisfactory, showing a complete wetting with a contact angle of 10.7° in the initial assessment and 6.6° in the evaluation after 5 seconds.

Made available in DSpace on 2020-12-12T02:31:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-03-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) The demand for bioplastics from renewable sources for a range of emerging applications has been as extensive as the efforts to find greener routes for their isolation from nature. Surfing this wave, we report on the production of flexible, optically semi-transparent onion-only bioplastics through different all-aqueous film-forming procedures encompassing hydrothermal, grinding, washing, and/or sieving pre-solvent casting steps. The onion bioplastics were extensively characterized targeting correlations among chemical structure, film-forming protocol, and film properties. HPLC evidenced insoluble carbohydrates/polysaccharides in all samples, though at different contents (11–44%) depending on processing, but washing lixiviated all soluble carbohydrates – the presence of ca. 14% of the latter in unwashed samples provided their films with reduced glass transition temperature – from 73–83 to 13 °C, as indicated by DSC; elastic modulus and tensile strength – from 1.5–3.2 GPa to 47 MPa and from 7–21 to 3 MPa, respectively; increased elongation at break – from 0.7–1.6% to 22%; and decreased contact angle with water – from 39-70° to 22° (in comparison with washed samples). Additionally, SEM provided morphological aspects; thermogravimetry indicated thermal stability profile; FTIR led to hydrogen bond energy [kJ] and distance [Å] as well as total crystallinity index (0.43–0.96), lateral order index (0.8–3.2), and hydrogen bonding intensity (13–4.7); and XRD determined the index of crystallinity (21–49%). Finally, the hydrophilic/hydrophobic nature, water barrier, and moisture sorption of the bioplastics were determined. Altogether, we herein depict the production of novel bioplastics made up exclusively of onion and used a range of characterization techniques to come up with relevant structure-processing-property correlations. São Paulo State University (UNESP) Institute of Chemistry Nanotechnology National Laboratory for Agriculture (LNNA) Embrapa Instrumentation University of Araraquara (Uniara) Laboratory of Biopolymers and Biomaterials (BIOPOLMAT) Chalmers University of Technology Department of Chemistry and Chemical Engineering São Paulo State University (UNESP) Institute of Chemistry FAPESP: 2014/23098-9 FAPESP: 2016/15504-2

Made available in DSpace on 2018-12-11T16:54:59Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-09-01 University Grants Commission Fabricating novel materials for biomedical applications mostly require the use of biodegradable materials. In this work biodegradable materials like polylactic acid (PLA) and chitosan (CHS) were used for designing electrospun mats. This work reports the physical and chemical characterization of the PLA–CHS composite, prepared by the electrospinning technique using a mixed solvent system. The addition of chitosan into PLA, offered decrease in fiber diameter in the composites with uniformity in the distribution of fibers with an optimum at 0.4wt% CHS. The fiber formation and the reduction in fiber diameter were confirmed by the SEM micrograph. The inverse gas chromatography and contact angle measurements supported the increase of hydrophobicity of the composite membrane with increase of filler concentration. The weak interaction between PLA and chitosan was confirmed by Fourier transform infrared spectroscopy and thermal analysis. The stability of the composite was established by zeta potential measurements. Cytotoxicity studies of the membranes were also carried out and found that up to 0.6% CHS the composite material was noncytotoxic. The current findings are very important for the design and development of new materials based on polylactic acid-chitosan composites for environmental and biomedical applications. [Figure not available: see fulltext.]. International and Interuniversity Centre for Nanoscience and Nanotechnology Mahatma Gandhi University, Priyadarsini Hills P.O. Department of Chemistry Mar Thoma College, Kuttapuzha P.O. Department of Chemistry C.M.S. College Food and Bioproduct Sciences University of Saskatchewan Faculty of Exact Science and Engineering University of Madeira CIIMAR University of Porto Institute of Chemistry-UNESP, CP 355, Zip 14801-970 Institute of Chemistry-UNESP, CP 355, Zip 14801-970

AIMS Obtain varieties of Gluconacetobacter hansenii from original strain ATCC 23729 with greater efficiency to produce bacterial cellulose (BC) membrane with better dry mass yield for application as support of sustained antimicrobials' drug release. METHODS AND RESULTS Application of different chemical and physical conditions (pH, temperature and UV light exposure) to obtain different G. hansenii varieties with high capacity to produce BC membranes. Characterization of the G. hansenii variants was performed by scanning electron microscopy (SEM) and optical microscopy of the colony-forming units. BC membrane produced was characterized by SEM, infrared spectroscopy and X-ray diffraction. The BC produced by variants isolated after incubation at 35°C showed elevated dry mass yield and high capacity of retention and sustained release of ceftriaxone antibiotic with the produced BC by original G. hansenii ATCC 23769 strain subjected to incubation at 28°C and with commercial BC. CONCLUSION The application of different chemical and physical conditions constitutes an important method to obtain varieties of micro-organisms with dissimilar metabolism advantageous in relation to the original strain in the BC production. SIGNIFICANCE AND IMPACT OF THE STUDY These results demonstrate the importance of in vivo studies for the application, in medicine, of BC membranes as support for antimicrobial-sustained release for the skin wound treatment.

Adsorption has been explored to minimize the pollution caused by dyes. This work relates the preparation of diethylenetriamine-modified cellulose (DetaCel) by reacting phthalic anhydride-modified cellulose (PhCel) with diethylenetriamine (Deta). Materials were characterized by Elemental Analysis and results showed a degree of incorporation of 5.55 ± 0.02 mmol of nitrogen per gram of modified material. The main bands observed for DetaCel by Fourier-Transform Infrared Spectroscospy (FTIR) were attributed to C N deformation (1330 cm−1) and N H stretching of amide (3400 cm−1), while Solid State Nuclear Magnetic Resonance of 13C (13C{1H}CP-MAS NMR) showed a signal at 164.6 ppm characteristic of amide group. Crystallinity index (CrI) obtained by X-Ray Diffraction (XRD) was 74.99 (Cel), 58.64 (PhCel) and 46.12% (DetaCel). Adsorbent matrices were employed to remove methyl orange (MO) and eosin (EY) dyes in aqueous medium. Data obtained experimentally from kinetic study had a better fit to the pseudo-first order, thus the adsorption process occurs in monolayer, with MO adsorption capacity by Cel and DetaCel of 2.19 and 65.45 mg g−1, respectively. For EY adsorption by Cel and DetaCel was 1.30 and 56.69 mg g−1, respectively. These results suggest that DetaCel can be used as an alternative potential for removal dyes in aqueous solution.

Made available in DSpace on 2018-11-26T15:29:19Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-07-01 Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) In this paper, cellulose triacetate (CTA) was produced from sugarcane bagasse and used as matrices for controlled release of paracetamol. Symmetric and asymmetric membranes were obtained by formulations of CTA/dichloromethane/drug and CTA/dichloromethane/water/drug, respectively, and they were characterized by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). Different morphologies of membranes were observed by SEM, and the incorporation of paracetamol was confirmed by lowering of the glass transition temperature (T-g) in the DSC curves. This indicates the existence of interactions between the matrix and the drug. The evaluation of drug release was based on the electrochemical monitoring of paracetamol through its oxidation at a glassy carbon electrode surface using square-wave voltammetry (SWV), which provides fast, precise and accurate in situ measurements. The studies showed a content release of 27% and 45% by the symmetric and asymmetric membranes, respectively, during 8h. Univ Fed Uberlandia, Inst Quim, BR-38400902 Uberlandia, MG, Brazil Univ Fed Uberlandia, Fac Ciencias Integradas Pontal, Ituiutaba, MG, Brazil Univ Estadual Paulista, Inst Quim, Rua Francisco Degni 55, Araraquara, SP, Brazil Univ Estadual Paulista, Inst Quim, Rua Francisco Degni 55, Araraquara, SP, Brazil FAPEMIG: CEX-APQ-01128/13

Bacterial cellulose (BC) and silk fibroin (SF) are natural biopolymers successfully applied in tissue engineering and biomedical fields. In this work nanocomposites based on BC and SF were prepared and characterized by scanning electron microscopy (SEM), infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). In addition, the investigation of cytocompatibility was done by MTT, XTT and Trypan Blue dye technique. Cellular adhesion and proliferation were detected additionally. The evaluation of genotoxicity was realized by micronucleus assay. In vitro tests showed that the material is non-cytotoxic or genotoxic. SEM images revealed a greater number of cells attached at the BC/SF:50% scaffold surface than the pure BC one, suggesting that the presence of fibroin improved cell attachment. This could be related to the SF amino acid sequence that acts as cell receptors facilitating cell adhesion and growth. Consequently, BC/SF:50% scaffolds configured an excellent option in bioengineering depicting its potential for tissue regeneration and cultivation of cells on nanocomposites.

In this work, transparent organic–inorganic nanocomposites membranes have been prepared by casting process using carboxymethylcellulose (CMC) as organic matrix and synthetic clay (laponite) as reinforcement inorganic filler. Pristine CMC and CMC-laponite nanocomposites films were prepared using different clay-to-polymer ratios and all the obtained membranes are optically transparent on the UV–vis range. Field emission scanning electron microscopy (FE-SEM) images of the nanocomposite films evidenced a homogeneous dispersion of clay in the polymer matrix. As result, mechanical properties of the membranes are deeply affected by the presence of clay, increasing the Young’s modulus and tensile strength values when clay content is increased. On the other hand, maximum strain values decrease when clay concentration is over 10 wt% in comparison to pristine CMC membrane. Thermal properties of CMC films are also influenced by the presence of clay platelets. The main weight loss step of the nanocomposites is shifted toward higher temperatures when compared to pristine CMC membrane, indicating that laponite particles are capable of protecting the polymer chains from thermal and oxidative decomposition. Water vapor permeability (Pw) trend also reveals a decrease in these values for the nanocomposites when clay concentration is high, achieving its minimum permeability at 17 wt% of clay content (which corresponds a decrease of 42% on Pw value in comparison to pristine CMC membrane).

Highly transparent biocomposite based on bacterial cellulose (BC) mat modified with poly(ethylene oxide-b-propylene oxide-b-ethylene oxide) block copolymer (EPE) were fabricated in situ during biosynthesis of bacterial cellulose in a static culture from Gluconacetobacter xylinum. The effect of the addition to the culture medium of water-soluble EPE block copolymer on structure, morphology, crystallinity, and final properties of the novel biocomposites was investigated at nano- and macroscale. High compatibility between components was confirmed by ATR-FTIR indicating hydrogen bond formation between the OH group of BC and the PEO block of EPE block copolymer. Structural properties of EPE/BC biocomposites showed a strong effect of EPE block copolymer on the morphology of the BC mats. Thus, the increase of the EPE block copolymer content lead to the generation of spherulites of PEO block, clearly visualized using AFM and MO technique, changing crystallinity of the final EPE/BC biocomposites investigated by XRD. Generally, EPE/BC biocomposites maintain thermal stability and mechanical properties of the BC mat being 1 wt % EPE/BC biocomposite material with the best properties. Biosynthesis of EPE/BC composites open new strategy to the utilization of water-soluble block copolymers in the preparation of BC mat based biocomposites with tunable properties.

Zidovudine (AZT) is the antiretroviral drug most frequently used for the treatment of Acquired Immunodeficiency Syndrome. Its low oral bioavailability demands the development of innovative strategies to overcome the first pass metabolism. The nasal route is an option for enhanced therapeutic efficacy and to reduce the extent of the first-pass effect. In this article, AZT loaded chitosan nanoparticles were prepared by a modified ionotropic gelation method with sodium tripolyphosphate. The increase proportion of CS (NP1 10:01 (w/w)) promoted the formation of smaller nanoparticles (260 nm), while raising the proportion of TPP (NP2 5:1 w/w) increased the nanoparticles size (330 nm). The incorporation of AZT increased the nanoparticles size for both AZT-loaded nanoparticles AZT-loaded NP1 (406 nm) and AZT-loaded NP2 (425 nm). The incorporation of AZT into NP1 did not change the electrophoretic mobility, however, in AZT-loaded NP2 there was a significant increase. The positive surface of the nanoparticles is very important for the mucoadhesive properties due interaction with the sialic groups of the mucin. Nuclear resonance magnetic data showed that the higher concentration of chitosan in the nanoparticles favored the interaction of few phosphate units (pyrophosphate) by ionic interaction Scanning electron microscopy, revealed that the nanoparticles are nearly spherical shape with porous surface. The entrapment efficiency of AZT, was 17.58% ± 1.48 and 11.02% ± 2.05 for NP1 and NP2, respectively. The measurement of the mucoadhesion force using mucin discs and nasal tissue obtained values of NP1 = 2.12 and NP2 = 4.62. In vitro permeation study showed that the nanoparticles promoted an increase in the flux of the drug through the nasal mucosa. In view of these results, chitosan nanoparticles were found to be a promising approach for the incorporation of hydrophilic drugs and these results suggest that the CS-containing nanoparticles have great potential for nasal AZT administration.

In the last several years, the use of renewable energy sources has increased; consequently, the number of studies regarding their efficiency has also increased. It is well known that fossil and atomic fuels will not last forever and that their use contributes to environmental pollution. Thus, nanostructured thin films have attracted attention due to numerous applications, including construction of photovoltaic energy generating and photoluminescence materials. Therefore, in this study, we prepared and characterized thin films supported on bacterial cellulose that were produced using the layer-by-layer (LbL) technique. The weak polyelectrolytes, such as poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA), combined with titanium dioxide (TiO2) and gold nanoparticles (Au NPs) were used to produce flexible devices capable of producing hydrogen gas (H2) by photocatalysis. The presence of the Au NPs and TiO2 in the films was confirmed using UV–vis spectroscopy, Rutherford backscattering spectromet...

Cellulose derivatives have been widely used as adsorbents for the removal of micropollutants such as drugs, dyes, and metals, due to their abundance, low cost and non-contaminating nature. In this context, several studies have been performed searching for new adsorbents (cellulose derivatives) efficient at contaminant removal from aqueous solutions. Thus, a new adsorbent was synthesized by chemical modification of cellulose with ethylenediamine in the absence of solvent and applied to the adsorption of amitriptyline (AMI) in aqueous solution. The modification reaction was confirmed by X-ray Diffraction (XRD), elemental analysis, Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetry/Differential Scanning Calorimeter (TG/DSC), solid state Nuclear Magnetic Resonance of 1H and 13C (1H-NMR and 13C-NMR). Moreover, the effectiveness of reaction was confirmed by computational calculations using Density Functional Theory (DFT) at level B3LYP/6-31G(d). This adsorption process was influenced by pH, time, concentration, temperature and did not show significant changes due to the ionic strength variation. Through these experiments, it was observed that the maximum adsorption capacity of AMI by CN polymer at 298 K, 300 min, and pH 7 was 87.66 ± 0.60 mg·g−1.

Made available in DSpace on 2018-11-26T17:41:49Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-11-15 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Bacterial cellulose (BC) has been extensively exploited for applications in materials science, biomedical and technological fields. The BC production demands culture media rich in carbon sources. Agro-forestry residues constitute an interesting source of nutrients for microorganism, but they are frequently wasted. For cashew crop, exudate is periodically extracted from the tree trunks to increase the production of cashew nut, the most valuable product from cashew trees that produces about 700 g of exudate/year, which remains wasted. Here, we associated the nutritional properties of residues from cashew tree with the need of carbon sources for BC, in attempt to valorize the residue and to decrease the costs of BC production. The carbon source from Hestrin Schramm culture medium was totally or partially replaced by cashew tree residues and the BC production was evaluated. The produced BC membrane in static medium was characterized by FTIR, SEM and TGA and the kinetics of production was determined, suggesting the cashew tree residues as a potential carbon source for BC production. Univ Araraquara Uniara, Lab Biopolimeros & Biomat BIOPOLMAT, Rua Carlos Gomes 1217, BR-14801320 Araraquara, SP, Brazil Univ Fed Piaui, Ctr Ciencias Nat, Lab Interdisciplinar Mat Avancados, Campus Univ Uninga, BR-64049550 Teresina, PI, Brazil Univ Fed Grande Dourados UFGD, Dept Quim, Fac Ciencias Exatas & Tecnol FACET, Rodovia Dourados Itahum,Km 12,Cidade Univ, BR-79804970 Dourados, MS, Brazil Univ Estadual Poulista Julio de Mesquita Filho, Inst Quim Araraquara, Dept Quim Geral & Inorgan, Rua Prof Francisco Degni,55 Jardim Quitandinha, BR-14800060 Araraquara, SP, Brazil Univ Estadual Poulista Julio de Mesquita Filho, Inst Quim Araraquara, Dept Quim Geral & Inorgan, Rua Prof Francisco Degni,55 Jardim Quitandinha, BR-14800060 Araraquara, SP, Brazil CAPES: 1514505

In this work we explored the fabrication of flexible and transparent hybrids of silk fibroin (SF) and epoxy-modified siloxane for photonic applications. It is well-known that regenerated SF solutions can form free-standing films with high transparency. Although SF has a restricted number of chemically reactive side groups, the main issues of as-cast pristine SF films regard the high solubility into aqueous media, brittleness, and low thermal stability. The design of SF films with enhanced functionality but high transparency triggers new opportunities on a broader range of applications in biophotonics. Here we present a simple, functional, yet remarkably versatile hybrid material derived from silica sol-gel process based on SF protein and (3-glycidyloxypropyl)trimethoxysilane (GPTMS), an organically modified silicon-alkoxide owning a reactive terminal epoxy group. Specifically, we investigated the effect of the addition of GPTMS into SF solutions on the processability, morphology, crystallinity, and mechanical and optical properties of the resulting hybrid films. Highly transparent (ca. 90%) and flexible free-standing hybrid films were achieved. Cell viability assays revealed that the hybrid films are noncytotoxic to rat osteoblast cells even at high GPTMS content (up to 70 wt %). The hybrid films showed enhanced thermal stability and were rich in organic (epoxy) and inorganic (silanol) functional groups according to the content of GPTMS. We also evaluated the successful preparation of high-quality optical red emissive SF hybrid films by loading YVO

Made available in DSpace on 2018-12-11T17:15:05Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-01-01 Bacterial cellulose/carboxymethylcelullose (BC/CMC) biocomposites with different DS-CMC (DS from 0.7 to 1.2) were developed in order to evaluate their impact as a drug delivery system. Biocomposites were loaded with methotrexate (MTX) as an alternative for the topical treatment of psoriasis. Scanning electron microscopy and atomic force microscopy showed that the CMC coated the cellulose nanofibers, leading to the decrease of the elastic modulus as the DS of CMC increased. BC/CMC0.9 exhibited the lower liquid uptake (up to 11 times lower), suggesting that the more linear structure of the intermediate substitute CMC grade (0.9) was able to interact more strongly with BC, resulting in a denser structure. All samples showed a typical burst release effect in the first 15 min of test, however the BC/CMC0.9 biocomposite promoted a slight lowering of MTX release rates, suggesting that the DS of CMC can be considered the key factor to modulate the BC properties. University of Araraquara – U NIARA Institute of Chemistry São Paulo State University – UNESP Interdisciplinary Laboratory of Advanced Materials Centro de Ciências da Natureza- CNN Federal University of Piaui – UFPI Group ‘Materials + Technologies’ (GMT) Department of Chemical and Environmental Engineering Engineering College of Gipuzkoa University of the Basque Country (UPV/EHU) Department of Drugs and Pharmaceuticals School of Pharmaceutical Sciences SãoPaulo State University – UNESP Institute of Chemistry São Paulo State University – UNESP Department of Drugs and Pharmaceuticals School of Pharmaceutical Sciences SãoPaulo State University – UNESP

Made available in DSpace on 2018-12-11T16:46:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-06-01 Eusko Jaurlaritza In this study fabrication and characterization of transparent nanostructured composite films based on cellulose triacetate (CTA) and poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (EPE) triblock copolymer were presented. The effect of the addition of EPE triblock copolymer on the thermal stability, morphology, and mechanical properties of cellulose triacetate films was investigated. The triblock EPE was chosen since PEO blocks interact favorably with CTA, whereas, PPO blocks remain immiscible which provokes a microphase separation. This allows to obtain EPE/CTA composite films with ordered microphase-separated structures where PPO spherical microdomains are well-dispersed in PEO/CTA matrix by simple solvent-evaporation process. During this process, PEO block chains selectively interact with CTA by strong interpolymer hydrogen-bonding while PPO block microseparated. The addition even 40 wt% of EPE leads to nanostructured EPE/CTA composite. The cytotoxicity assay of CTA and EPE/CTA composite films confirm non-toxic character of designed transparent nanostructured composites based on sustainable matrices. ‘Materials + Technologies’ Group (GMT) Department of Chemical and Environmental Engineering Faculty of Engineering University of the Basque Country (UPV/EHU), Plaza Europa 1 Faculty of Engineering Vitoria-Gasteiz University of the Basque Country (UPV/EHU), C/Nieves Cano Laboratory of Photonic Materials Institute of Chemistry Sao Paulo State University (UNESP) Medicinal Chemistry and Regenerative Medicine (QUIMMERA) University Center of Araraquara (UNIARA) Laboratory of Photonic Materials Institute of Chemistry Sao Paulo State University (UNESP)

Made available in DSpace on 2018-12-11T17:08:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-02-10 Although resistant starch/pectin (RS/P) films have previously displayed suitable properties for colon-specific drug delivery, nanocomposite films were developed aiming to enhance physicochemical, thermal, mechanical and barrier properties, as well as the low oral bioavailability of methotrexate (MTX). FEG-SEM micrographs of nanocomposite films showed different interaction patterns occurring among nanocellulose and RS/P. The nanofiller addition led to an increase in the thermal stability, probably due to its interaction with RS crystalline double helices. Results also displayed an improvement of the puncture strength, while barrier properties revealed a low water vapor permeability. Ex vivo bioadhesion test displayed the nanocomposites films to interact strongly with porcine gastrointestinal mucosa. In vitro drug release studies showed that the films developed enhanced the drug dissolution rates with approximately 80% of MTX release in 150 min, suggesting the potential of these materials as a poor solubility drugs carrier, which constitutes an important tool for enhancing oral bioavailability. Interdisciplinary Laboratory of Advanced Materials Centro de Ciências da Natureza – CNN Universidade Federal do Piauí – UFPI Department of Drugs and Pharmaceuticals Faculty of Pharmaceutical Sciences São Paulo State University-UNESP Institute of Chemistry São Paulo State University – UNESP Universidade de Araraquara – UNIARA Department of Drugs and Pharmaceuticals Faculty of Pharmaceutical Sciences São Paulo State University-UNESP Institute of Chemistry São Paulo State University – UNESP

RESUMO Este trabalho almejou produzir celulose bacteriana (CB), obter nanocristais de celulose bacteriana (NCCB), incorporar NCCB como reforço em poli(L-ácido láctico) (PLLA) e avaliar propriedades destes bionanocompósitos. Foram produzidas membranas de CB provenientes da bactéria Gluconacetobacter hansenii. A partir das membranas foram obtidos NCCB por hidrólise com ácido sulfúrico (H2SO4), com base em 11 experimentos. Os parâmetros variados nos experimentos foram: concentração de H2SO4, temperatura e tempo. Pode-se definir critérios de obtenção de NCCB por análise termogravimétrica (TGA) e análise de espalhamento dinâmico de luz (DLS). Principais resultados indicam possibilidade de obtenção na condição de: 80% de concentração de H2SO4 (m/m), 60 ºC e 60 min. Para esta condição obteve-se tamanhos adequados dos NCCB (média de 388 nm), potencial zeta adequado (-38 mV) e estabilidade térmica adequada (Tonset2 = 301,9 ºC). Posteriormente, NCCB obtidos conforme critérios definidos foram incorporados ao PLLA em duas concentrações (2,5 e 5%), utilizando dois métodos (sem e com funcionalização dos NCCB). Os bionanocompósitos preparados foram caracterizados por TGA e calorimetria explanatória diferencial (DSC). Resultados das técnicas de caracterização dos bionanocompósitos foram comparados com resultados do PLLA puro. Principais resultados em relação aos métodos, revelam a importância da funcionalização dos NCCB antes de incorporá-los ao PLLA. Sobre a concentração de reforço utilizada, o aumento da estabilidade térmica foi gradual, conforme teor de reforço, sendo que para o bionanocompósito com 5% de NCCB funcionalizados o incremento foi de 10,4 ºC na Tonset2 em relação ao PLLA puro. Contudo, o grau de cristalinidade diminuiu (Xc do PLLA puro = 40,38% e Xc do bionanocompósito com 5% de NCCB funcionalizados = 24,73%). Conclui-se que a adição de NCCB em PLLA é ambientalmente viável e promove melhoria de propriedades. ABSTRACT This work aimed to produce bacterial cellulose, to obtain bacterial cellulose nanocrystals, to incorporate nanocrystals as a reinforcement in poly(L-lactic acid) and to evaluate the properties of these bionanocomposites. Bacterial cellulose membranes from the bacterium Gluconacetobacter hansenii were produced. From the membranes were obtained nanocrystals by hydrolysis with sulfuric acid (H2SO4), based on 11 experiments. The parameters varied in the experiments were: concentration of H2SO4, temperature and time. It is possible to define criteria for obtaining nanocrystals by thermogravimetric analysis and analysis of dynamic scattering of light. Main results indicate the possibility of obtaining in the condition of: 80% concentration of H2SO4 (m/m), 60 °C and 60 min. For this condition, suitable sizes of the nanocrystals (mean 388 nm), suitable zeta potential (-38 mV) and adequate thermal stability (Tonset2 = 301.9 °C) were obtained. Subsequently, nanocrystals obtained according to defined criteria were incorporated into poly(L-lactic acid) in two concentrations (2,5 and 5%), using two methods (without and with functionalization of nanocrystals). The prepared bionanocomposites were characterized by thermogravimetric analysis and differential explanatory calorimetry. Results of the techniques of characterization of bionanocomposites were compared with results of pure poly(L-lactic acid). Main results regarding the methods, reveal the importance of the functionalization of the nanocrystals before incorporating them to the poly(L-lactic acid). On the reinforcement concentration used, the increase of the thermal stability was gradual, according to reinforcement content, and for the bionanocomposite with 5% functionalized nanocrystals the increase was of 10,4 ºC in the Tonset2 in relation to the poly(L-lactic acid) pure. However, the degree of crystallinity decreased (Xc of pure PLLA = 40,38% and Xc of bionanocomposite with 5% of functionalized nanocrystals = 24,73%). It is concluded that the addition of bacterial cellulose nanocrystals in poly(L-lactic acid) is environmentally feasible and improves properties.

Made available in DSpace on 2018-11-28T00:18:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-12-06 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundacao Oswaldo Cruz - Programa de Apoio a Pesquisas Estrategicas (FIOCRUZ-PAPES IV) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) The treatment of leishmaniasis still relies on drugs with potentially serious adverse effects. Herein, we tested a topical formulation of bacterial cellulose (BC) membranes containing Diethyldithiocarbamate (DETC), a superoxide dismutase 1 inhibitor. Leishmania-infected macrophages exposed to BC-DETC resulted in parasite killing, without pronounced toxic effects to host cells. This outcome was associated with lower SOD1 activity and higher production of superoxide and cytokine mediators. Topical application of BC-DETC significantly decreased lesion size, parasite load and the inflammatory response at the infection site, as well as the production of both IFN-gamma and TNF. Combination of topical BC-DETC plus intraperitoneal Sb-v also significantly reduced disease development and parasite load. The leishmanicidal effect of BC-DETC was extended to human macrophages infected with L. braziliensis, highlighting the feasibility of BC-DETC as a topical formulation for chemotherapy of cutaneous leishmaniasis caused by L. braziliensis. Fiocruz MS, Inst Goncalo Moniz, Salvador, BA, Brazil Univ Estadual Paulista, Inst Quim, Araraquara, SP, Brazil Univ Araraquara UNIARA, Araraquara, SP, Brazil Katholieke Univ Leuven, Rega Inst Med Res, Dept Microbiol & Immunol, Leuven, Belgium INCT, Inst Invest Imunol 3, Sao Paulo, Brazil Univ Estadual Paulista, Inst Quim, Araraquara, SP, Brazil CNPq: 482193/2012-3 Fundacao Oswaldo Cruz - Programa de Apoio a Pesquisas Estrategicas (FIOCRUZ-PAPES IV): 407437/2012-6 CNPq: 161535/2011-9

New nanocomposites based on bacterial cellulose nanofibers (BCN) and polyurethane (PU) prepolymer were prepared and characterized by SEM, FT-IR, XRD, and TG/DTG analyses. An improvement of the interface reaction between the BCN and the PU prepolymer was obtained by a solvent exchange process. FT-IR results showed the main urethane band at 2,270 cm−1 to PU prepolymer; however, in nanocomposites new bands appear as disubstituted urea at 1,650 and 1,550 cm−1. In addition, the observed decrease in the intensity of the hydroxyl band (3,500 cm−1) suggests an interaction between BCN hydroxyls and NCO-free groups. The nanocomposites presented a non-crystalline character, significant thermal stability (up to 230 °C) and low water absorption when compared to pristine BCN.

Made available in DSpace on 2018-12-11T17:23:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-09-01 This paper describes the preparation of Sodium Polyphosphates Coacervates (NaPC) through the direct addition of different methanol molar fractions to a sodium polyphosphate solution. The presence of methanol reduces the dielectric constant medium and it promotes the coacervate formation. Rheology measurement shows that the NaPC viscosity is dependent on a methanol molar fraction, which is caused by the dielectric constant reduction of the water-methanol mixture. Raman spectra for the lyophilized NaPC show that the symmetric P-Ot stretching mode is more sensitive than the symmetric P-Ob stretching mode, due to the approach of the adjacent polyphosphate chains. The 31P NMR spectra also confirm a decrease in the Q2/Q1 ratio because of the methanol content. Besides, we have obtained transparent soft Glass-Materials to melt NaPC at 800 °C. Institute of Chemistry – São Paulo State University – Unesp, P.O. Box 355 Laboratório de Biopolímeros e Biomateriais (BioPolMat) – Centro Universitário de Araraquara (UNIARA) Núcleo de Espectroscopia e Estrutura Molecular – NEEM Departamento de Química Instituto de Ciências Exatas Universidade Federal de Juiz de Fora NUPIS (Núcleo de Pesquisa em Instrumentação e Separações Analíticas) Departamento de Química Instituto de Ciências Exatas Universidade Federal de Juiz de Fora School of Pharmaceutical Sciences São Paulo State University – UNESP Institute of Chemistry – São Paulo State University – Unesp, P.O. Box 355 School of Pharmaceutical Sciences São Paulo State University – UNESP

Made available in DSpace on 2018-12-11T17:23:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-07-15 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) The preparation of composite materials has gained tremendous attention due to the potential synergy of the combined materials. Here we fabricate novel thermal/electrical responsive photonic composite films combining cellulose nanocrystals (CNC) with a low molecular weight nematic liquid crystal (NLC), 4′-(hexyloxy)-4-biphenylcarbonitrile (HOBC). The obtained composite material combines both intense structural coloration of photonic cellulose and thermal and conductive properties of NLC. Scanning electron microscopy (SEM) results confirmed that liquid crystals coated CNC films maintain chiral nematic structure characteristic of CNC film and simultaneously, transversal cross-section scanning electron microscopy images indicated penetration of liquid crystals through the CNC layers. Investigated composite film maintain NLC optical properties being switchable as a function of temperature during heating/cooling cycles. The relationship between the morphology and thermoresponsive in the micro/nanostructured materials was investigated by using transmission optical microscopy (TOM). Conductive response of the composite films was proved by Electrostatic force microscopy (EFM) measurement. Designed thermo- and electro-responsive materials open novel simple pathway of fabrication of CNC-based materials with tunable properties. São Paulo State University (Unesp) Institute of Chemistry, CP 355 Group ‘Materials + Technologies’ (GMT) Department of Chemical and Environmental Engineering Engineering College of Gipuzkoa University of the Basque Country (UPV/EHU), Plaza Europa 1 Laboratório de Biopolímeros e biomateriais (BioPolMat) Universidade de Araraquara São Paulo State University (Unesp) Institute of Chemistry, CP 355

This study aimed to evaluate the cytotoxicity of a calcium aluminate cement (EndoBinder) containing different radiopacifiers, Bi2O3, ZnO or ZrO2, compared with Mineral Trioxide Aggregate (MTA). According to ISO 10993-12:2012 (E) recommendations, 0.2 g of each cement were applied in transwell inserts and placed in 24-well culture plates containing 1 mL of culture medium (DMEM). After 24 h of incubation, the extracts (DMEM containing components released from the cements) were applied to immortalized odontoblast-like MDPC-23 cells. Cell viability (MTT test), alkaline phosphatase activity (ALP), total protein production and cell morphology (Scanning Electron Microscopy - SEM) were evaluated. The volume of 50 µL of extract was used to determine the chemical elements released by the cements using Energy Dispersive Spectroscopy (EDS). The following groups were established (n=6): NC - negative control (without treatment); EB - EndoBinder without radiopacifier; EBBO - EndoBinder+Bi2O3; EBZnO - EndoBinder+ZnO; EBZrO - EndoBinder+ZrO2 and WMTA - White MTA. Data were subjected to statistical analysis (Kruskal-Wallis test, level of significance=5%). Cells exposed to the different versions of EndoBinder presented small reduction in viability, total protein production and ALP activity, with values similar to the NC and WMTA groups (p>0.05). Different elements (C, O, Na, Al, P, Si, Cl, Bi, K) released by the cements were detected in the extracts. However, the cells had no significant changes in their morphology. EndoBinder and MTA did not affect negatively the metabolism of the odontoblastic-like cells, showing it to be cytocompatible, irrespective of the used radiopacifier. Resumo Este estudo avaliou a citotoxicidade de um cimento de aluminato de cálcio (EndoBinder) contendo diferentes radiopacificadores, Bi2O3, ZnO ou ZrO2, comparativamente ao trióxido mineral agregado (MTA). Seguindo a norma ISO 10993-12:2012 (E), 0,2 g de cada cimento foi aplicada em insertos transwell, que foram colocados em placas de cultura de 24 wells contendo 1 mL de meio de cultura (DMEM). Após 24 h de incubação, os extratos (DMEM contendo componentes liberados dos cimentos) foram aplicados sobre células pulpares imortalizadas MDPC-23. Viabilidade celular (teste de MTT), atividade da fosfatase alcalina (ALP), produção de proteína total e a morfologia das células (Microscópio Eletrônico de Varredura - MEV) foram avaliadas. Um volume de 50 µL do extrato foi utilizado para determinar, através de Espectroscopia de Energia Dispersiva (EDS), os elementos químicos liberados pelos cimentos. Os seguintes grupos foram estabelecidos (n=6): NC - controle negativo (sem tratamento); EB - EndoBinder sem radiopacificador; EBBO - EndoBinder+Bi2O3; EBZnO - EndoBinder+ZnO; EBZrO - EndoBinder+ZrO2 e WMTA - MTA branco. Os dados foram submetidos à análise estatística (teste de Kruskal-Wallis, nível de significância=5%). Células expostas às diferentes versões de EndoBinder apresentaram pequena redução na viabilidade, produção de proteína total e atividade da ALP, com valores semelhantes aos grupos NC e WMTA (p>0,05). Diversos elementos (C, O, Na, Al, P, Si, Cl, Bi, K) liberados pelos cimentos foram detectados nos extratos. Entretanto, as células não apresentaram alterações significativas em sua morfologia. EndoBinder e MTA, não afetaram negativamente o metabolismo das células odontoblastóides, mostrando-se citocompatíveis, independente do radiopacificador utilizado.

Made available in DSpace on 2018-12-11T17:23:05Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-01-01. Added 1 bitstream(s) on 2019-10-09T18:32:00Z : No. of bitstreams: 1 S1516-14392016000100106.pdf: 4613088 bytes, checksum: 245d5ddc48747bc149d91e95ddbf0aee (MD5) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) This study compares a wound dressing based on bacterial cellulose/collagen (BC/COL) hydrogel in rat dorsum with commercial collagenase ointment and untreated wound. The hydrogel was characterized by Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA), Fourier transformed-Infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). According to the In vivo test and macroscopic evaluation, BC/COL hydrogel showed a better repair of wounds and promoted statistically significant differences of tissue repair between treatments on the 7th day after surgery. Better quality, quantity and orientation evaluation of collagen fibers (p=0.0001) were observed in the BC/COL hydrogel and collagenase ointment groups in relation to the control group. The BC/COL hydrogel promoted better wound healing than collagenase and the control group, therefore, it can be considered a potential wound dressing for skin regeneration. Programa de Pos Graduacao Interunidades Bioengenharia-EESC/FMRP/IQSC-USP, Av. Trabalhador Sao-carlense, 400 Laboratorio de Morfologia Universidade Estadual Paulista-UNESP, Rua Humaita, 1680 Instituto de Quimica Universidade Estadual Paulista-UNESP, Rua Prof. Francisco Degni, 55 Laboratorio de Biopolimeros e Biomateriais (BioPolMat) Centro Universitario de Araraquara-UNIARA, Rua Voluntarios da Patria, 1309 Instituto de Quimica de Sao Carlos/USP, Av. Trabalhador Sao-carlense, 400 Laboratorio de Morfologia Universidade Estadual Paulista-UNESP, Rua Humaita, 1680 Instituto de Quimica Universidade Estadual Paulista-UNESP, Rua Prof. Francisco Degni, 55

The addition of calcium chloride eletrolyte to sodium polyphosphate solutions lead to Calcium polyphosphate coacervates. The effects of a thermal treatment were investigated with the objective to increase the relative stability of the obtained material. Thermogravimetry analysis indicates that coacervates became less hydrophilic and more thermally stable after the thermal treatment. Crystallization was identified through differential scanning calorimetry and X-ray diffraction. Morphological changes were observed after the thermal treatment by scanning electron microscopy. N2 adsorption–desorption isotherms suggest that both materials, thermally treated or not, display type IV isotherms, low superficial area and mesoporous structure. Stability experiments in solutions at different pH values show that the thermally treated calcium polyphosphate is relatively more stable than the non-treated coacervate.

Self-supported organic-inorganic hybrid trans- parent films have been prepared from bacterial cellulose and boehmite. SEM results indicate that the BC membranes are covered by Boehmite and XRD patterns suggest structural changes on cellulose due to Boehmite addition. Thermal stability is accessed through TG curves and is dependent on Boehmite content. Transparency, as evalu- ated by UV-Vis absorption, increases with increasing content of boehmite suggesting application of these mate- rials as transparent substrates for opto-electronic devices.

Made available in DSpace on 2018-11-26T15:28:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-12-15 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) Cellulose nanocrystals (CNs) were extracted from different sources by acid hydrolysis using H2SO4 and HCI. The thermal decomposition of resulting CNs was studied by thermogravimetric analysis (TGA). The kinetic parameters were determined using the Flynn-Wall-Ozawa (FWO) and Kissinger methods. CNs were also characterized by X-ray diffraction (XRD), Atomic Force Microscopy (AFM), elemental analysis (EA), Zeta Potential (ZP) and degree of polymerization (DP). The results of the XRD analysis showed different profiles, making it possible to differentiate cellulose I from cellulose II. The results obtained by the FWO method showed that cellulose II CNs had an increased activation energy (E-a) with conversion (alpha), while in CNs of cellulose I the E-a remained constant or decreased slightly. This difference between E-a values for the thermal decomposition of CNs was mainly attributed to different crystalline arrangements of cellulose land cellulose II, and to the type of acid employed. (C) 2015 Elsevier B.V. All rights reserved. Univ Fed Uberlandia, Inst Quim, BR-38400902 Uberlandia, MG, Brazil Univ Fed Ouro Preto, Inst Ciencias Exatas & Biol, Dept Quim, BR-35450000 Ouro Preto, MG, Brazil Univ Estadual Paulista Julio de Mesquita, Inst Quim Araraquara, BR-14800900 Sao Paulo, Brazil Univ Fed Triangulo Mineiro, Inst Ciencias Exatas Nat & Educ, BR-38064200 Uberaba, MG, Brazil Univ Estadual Paulista Julio de Mesquita, Inst Quim Araraquara, BR-14800900 Sao Paulo, Brazil

Conducting composite membranes of bacterial cellulose (BC) and polyaniline doped with dodecylbenzene sulfonic acid (PAni.DBSA) were successfully prepared by the in situ chemical polymerization of aniline in the presence of hydrated BC sheets. The polymerization was performed with ammonium peroxydisulfate as the oxidant agent and different amounts of DBSA. The composites were characterized by X-ray diffraction, attenuation reflectance Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), impedance spectroscopy and small angle X ray scattering (SAXS). The highest electrical conductivity value was achieved by using a DBSA/aniline molar ratio of 1.5 because this condition provided a better penetration of PAni.DBSA chains inside the hydrated BC sheet, as observed by SEM. The in situ polymerization gives rise to conducting membranes with the surface constituted by different degree roughness as indicated by Nyquist plots obtained from impedance spectroscopy and confirmed by SAXS measurements. This preliminary work provides a new way to prepare cellulose-polyaniline conducting membranes which find potential applications as electronic devices, sensors, intelligent clothes, etc.

The propolis produced in Southeastern Brazil is known as green propolis (BGP) because of its color and the most important plant source is Baccharis dracunculifolia. Several authors reported biological activities such as antiulcer, anti-inflammator, antimutagenic, antifungal/antibacterial, antileishmanial/antiplasmodial for the BGP. For this reason, BGP has been extensively employed in food and beverages, thus helping improve health and preventing diseases. Some authors related that the biological activities of BGP are mostly due to its high levels of prenylated ρ-coumaric acids derivatives, mainly artepillin C. The inclusion complex between Brazilian green propolis (BGP) with hydroxypropyl-β-cyclodextrin (HP-β-CD) was prepared and its characterization was investigated by different analytical techniques (X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetry) and suggesting that propolis was molecularly dispersed in the HP-β-CD matrix. The increasing solubility of chemical constituents was determined using quantitation methods for total flavonoids and polyphenols. Furthermore, it was developed a method for the quantitation and identification of the main compounds by high-performance liquid chromatography in order to evaluate the increasing water solubility of each constituent in aqueous BGP extract (aromadendrin, isosakuranetin, and artepillin C). The antioxidant activity was evaluated by chemical assay 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging.

In this study, microcrystalline cellulose (MCC) was prepared from the acid hydrolysis of bacterial cellulose (BC) produced in culture medium of static Acetobacter xylinum. The MCC-BC produced an average particle size between 70 and 90 μm and a degree of polymerization (DP) of 250. The characterization of samples was performed by thermogravimetric analysis, X-ray diffraction, and scanning electron microscopy (SEM). The MCC shows a lower thermal stability than the pristine cellulose, which was expected due to the decrease in the DP during the hydrolysis process. In addition, from X-ray diffractograms, we observed a change in the crystalline structure. The images of SEM for the BC and MCC show clear differences with modifications of BC fiber structure and production of particles with characteristics similar to commercial MCC.

The increase in sugarcane production and processing in order to obtain important products such as sugar and ethanol has the negative aspect of also increasing industrial residues. The most important residues originated during processing are bagasse, hydrolyzed bagasse, filter cake, vinasse, and ash. Thermal analysis revealed that these residues have peculiar properties, such as the presence of lignocellulosic material, except in the ash. The amount of organic matter decreases during the treatment process, due to the addition of chemical products to the residues, which are responsible for some alteration in their thermal properties. Colorimetric analysis showed considerable K and P concentrations in the vinasse and filter-cake residues. EDX and infrared spectroscopy showed the presence of Si in the residues. A higher percent of Si in ash sample was also observed, as a product of the thermal decomposition, by TG, FTIR, and X-ray diffractometry.

Bacterial cellulose (BC)/poly(3-hydroxybutyrate) (PHB) composite membranes were prepared from chloroform-swollen BC membranes and PHB chloroform solutions. Relative contents were varied from 25 to 90 wt.% of PHB. Macroscopically homogeneous composite membranes were characterized by scanning electron microscopy, Fourier-transformed infrared spectroscopy, X rays diffraction, thermal analysis and stress–strain measurements. Depending on the relative compositions membranes coating of BC microfibrils by PHB and PHB precipitation inside the BC 3D network of cellulose fibers could be observed. Improved mechanical properties were observed for the composites compared to the individual components suggesting potential applications for the new biodegradable materials.

Transparent amorphous bulk materials have been prepared through the coacervation process of sodium polyphosphate and Ni2+ and Co2+ chloride solutions. Structural and spectroscopic properties were analyzed by X-ray diffraction, thermogravimetric analysis, UV–vis, infrared and Raman spectroscopic techniques. Different optical properties and water absorption tendencies were observed for the polyphosphate coacervates. The symmetric P–Ob and P–Ot stretching modes on the Raman spectra for the coacervates and the sodium polyphosphate revealed the coordination processes of the polyphosphate chains to the metal ions, including the effects of the water coordination outside the polyphosphate cages, connecting the adjacent chains. Based on data collected from the electronic spectra, these materials can present important technological applicability. Being transparent materials, these glasses can be used as absorption filters with pass-band between 600 and 500 nm for the Ni coacervate, and above 600 nm for the Co coacervate.

Quercetin is a flavonoid very well studied and has already entered clinical trials emerging as prospective anticancer drug candidate. In addition, quercetin has being reported to its free-radical scavenging activity and suggests potential uses for the prevention and treatment of pathologies as atherosclerosis, chronic inflammation, and others. However, quercetin is sparingly soluble in water, which may be responsible for its limited absorption upon oral administration. The solid dispersion of quercetin with polyvinylpyrrolidone Kollidon® 25 (PVP K25) suggests an interesting way to increase quercetin solubility, antioxidant activity, and consequently bioavailability. Then, the purpose of this study was to prepare solid dispersions of quercetin with PVP K25 and evaluate their thermal characterization, antioxidant activity and quercetin improvement solubility. For this purpose, quercetin-PVP K25 solutions were dried and quercetin-PVP K25 solids were obtained. The formation of quercetin-PVP K25 solid dispersion was evaluated by solubility studies, powder X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), thermogravimetry (TG), and antioxidant activity. It was observed that PVP K25 was able to provide quercetin clear aqueous solutions and that quercetin solubility was increased in a PVP K25 concentration dependent manner, improving solubility even 436-fold the pure quercetin. The results obtained with XRD, FT-IR, DSC, and TG demonstrated possible quercetin-PVP K25 solid dispersion formation. Besides, the antioxidant activity of the quercetin-PVP K25 solid dispersions dissolved in aqueous solution and pure quercetin dissolved in methanol showed IC50 value of 0.61 ± 0.03 and 1.00 ± 0.02 μg/mL, respectively, demonstrating that the solid dispersions presented a significant increase in antioxidant activity (P < 0.05). Putting results together, it was possible to conclude there was the formation of quercetin-PVP K25 solid dispersion.

Bacterial cellulose (BC) has been considered a promising biopolymer with applications in several areas of knowledge, including medicine, mainly due to its ability to assist in the treatment of dermal lesions. Many groups and companies have been making efforts to develop new BC-based materials in order to add new characteristics and therapeutic possibilities. Recently, Seven Indústria de Produtos Biotecnológicos Ltda company developed a BC-based hydrogel aiming to verify the interaction among the formulation components, its potential for wound healing and biocompatibility studies. BC-based hydrogel was characterized and compared with pristine BC film. Physicochemical characterization includes rheological measurements, thermal analyses, field emission gun - scanning electron microscopy (FE-SEM) and in vitro cell migration. BC-based hydrogel showed adequate interaction among the components of the formulation, which may positively influence its stability. In addition, the BC-based hydrogel accelerated the healing processes demonstrating its potential in dermal lesion treatment.

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T19:01:49Z No. of bitstreams: 1 S0104-14282010000100014.pdf: 1602377 bytes, checksum: efefc2d6eafb2cbf49b13be2a732229c (MD5) Made available in DSpace on 2013-08-22T19:01:49Z (GMT). No. of bitstreams: 1 S0104-14282010000100014.pdf: 1602377 bytes, checksum: efefc2d6eafb2cbf49b13be2a732229c (MD5) Previous issue date: 2010-01-01 Made available in DSpace on 2013-09-30T20:02:12Z (GMT). No. of bitstreams: 2 S0104-14282010000100014.pdf: 1602377 bytes, checksum: efefc2d6eafb2cbf49b13be2a732229c (MD5) S0104-14282010000100014.pdf.txt: 25573 bytes, checksum: 5ec42744a0d33f24a3f172f9701cc7b0 (MD5) Previous issue date: 2010-01-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T14:19:57Z No. of bitstreams: 2 S0104-14282010000100014.pdf: 1602377 bytes, checksum: efefc2d6eafb2cbf49b13be2a732229c (MD5) S0104-14282010000100014.pdf.txt: 25573 bytes, checksum: 5ec42744a0d33f24a3f172f9701cc7b0 (MD5) Made available in DSpace on 2014-05-20T14:19:57Z (GMT). No. of bitstreams: 2 S0104-14282010000100014.pdf: 1602377 bytes, checksum: efefc2d6eafb2cbf49b13be2a732229c (MD5) S0104-14282010000100014.pdf.txt: 25573 bytes, checksum: 5ec42744a0d33f24a3f172f9701cc7b0 (MD5) Previous issue date: 2010-01-01 Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) A simple method was developed to load a large amount of silver nanoparticles into bacterial cellulose (BC) produced by Gluconacetobacter xylinus in a controlled manner. Due to the high electron-rich oxygen density in the BC macromolecules and the large surface area of the BC nanoporous structure as an effective nanoreactor, the in situ direct metallization technique was successfully used to synthesize Ag nanoparticles with an average diameter of 30 nm and a loading content of at least 5 wt. (%), approximately. This novel procedure provides an easy and economical way to manufacture Ag nanoparticles supported on a porous membrane for various biomedical applications. These composite fibers showed nearly 100% antibacterial activity (elimination of microorganisms) against Escherichia coli because of the presence of the silver nanoparticles. UERJ Departamento de Química Orgânica UNESP Instituto de Química UNESP Instituto de Química FAPERJ: APQ1E-26/171.289/2006 CNPq: 473687/2008-9

The number of the cities with canalized water and sewage treatment stations has increased lately and consequently having in mind the great concern on environment preservation and the quality of the water used by society. However, these stations are nowadays causing another kind of problem: a huge quantity of sludge as residue. Due to the implication of the residue on the environment and, consequently, to human life quality, performing of an accurate investigation about the components of such sludge, as well as the thermal stability of this residue in the environment become necessary. This paper presents a study on sludge from water and sewage treatment station, as well as the thermal characterization of residue. Such study was performed through FTIR, atomic absorption, thermoanalytical (TG/DTG, DTA) techniques, that made it possible to observe that the main components of the sludge are clay, carbonates and organic substance, presenting a low rate of metals and a unique thermal behavior since the sludge from the treatment station has a higher thermal stability.

Amorphous Mn2+ polyphosphate materials were prepared at room temperature through the coacervation of polyphosphate solutions. These new materials display the typical Mn2+ red emission with a broad band centered at 15,290 cm−1 (bandwidth—1,320 cm−1). Excitation spectra display typical Mn2+ (d5) absorption bands assigned to transitions from the 6A1g ground state to the 4T2g, (4A1g, 4Eg), 4T2g, and 4T1g Mn2+ excited states. Transition energies allow estimating the Mn2+ ligand field strength as intermediate between the one observed in Mn2+ aqueous solutions and the one observed in Mn2+ phosphate glasses. Azo dyes, methyl red and methyl orange, were incorporated into the manganese polyphosphate coacervates structure. Raman scattering and visible light reflectance results show azo dyes acid forms inside the hydrated polyphosphate structure and sensitivity to the atmosphere pH. Release of azo dyes species was observed from these new solid hybrid materials in aqueous medium.

Bacterial cellulose (BC) membranes produced by gram-negative, acetic acid bacteria (Gluconacetobacter xylinus), were used as flexible substrates for the fabrication of Organic Light Emitting Diodes (OLED). In order to achieve the necessary conductive properties indium tin oxide (ITO) thin films were deposited onto the membrane at room temperature using radio frequency (r.f.) magnetron sputtering with an r.f. power of 30 W, at pressure of 8 mPa in Ar atmosphere without any subsequent thermal treatment. Visible light transmittance of about 40% was observed. Resistivity, mobility and carrier concentration of deposited ITO films were 4.90 × 10− 4 Ohm cm, 8.08 cm2/V-s and − 1.5 × 1021 cm− 3, respectively, comparable with commercial ITO substrates. In order to demonstrate the feasibility of devices based on BC membranes three OLEDs with different substrates were produced: a reference one with commercial ITO on glass, a second one with a SiO2 thin film interlayer between the BC membrane and the ITO layer and a third one just with ITO deposited directly on the BC membrane. The observed OLED luminance ratio was: 1; 0.5; 0.25 respectively, with 2400 cd/m2 as the value for the reference OLED. These preliminary results show clearly that the functionalized biopolymer, biodegradable, biocompatible bacterial cellulose membranes can be successfully used as substrate in flexible organic optoelectronic devices.

In this work, the viability of recycling newspaper for producing cellulose acetate was tested. Newspaper recycling is extremely important not only for the environment preservation, but also from the economical point of view of aggregating value to this residue. Cellulose acetate was produced from a homogeneous acetylation, and then characterized by FTIR, DSC and TGA. Acetylation times were 48 h for as received newspaper (CA48) and 24 h for delignified newspaper (CA24), resulting in cellulose diacetate (DS = 1.98 ± 0.22) for CA48 and cellulose triacetate (DS = 2.79 ± 0.02) for CA24, respectively. Membranes of these materials were produced and characterized according to the previously mentioned techniques and by measurements of water vapor flux, which were compared to membranes of nanofiltration SG from Osmonix®. Results showed that independently of a purification step, it is possible to produce cellulose acetate membranes through the chemical recycling of newspaper and that membrane CA24 presents thermal stability comparable to membranes produced of commercial cellulose acetate.