A three-dimensional layer-by-layer (LbL) structure composed by xanthan and galactomannan biopolym... more A three-dimensional layer-by-layer (LbL) structure composed by xanthan and galactomannan biopolymers over dioctadecyldimethylammonium bromide (DODAB) liposome template was proposed and characterized for protein drug delivery. The polymers and the surfactant interaction were sufficiently strong to create a LbL structure up to 8 layers, evaluated using quartz crystal microbalance (QCM) and zeta potential analysis. The polymer-liposome binding enthalpy was determined by isothermal titration calorimetry (ITC). The bilayer of biopolymer-coated liposomes with diameters of 165 (±15)nm, measured by dynamic light scattering (DLS), and ζ-potential of -4 (±13)mV. These bilayer-coated nanoparticles increased up to 5 times the sustained release of epidermal growth factor (EGF) at a first order rate of 0.005min(-1). This system could be useful for improving the release profile of low-stability drugs like EGF.
The N-carboxymethylchitosan (N-CMCh) is a polyelectrolite with negative charge formed by the carb... more The N-carboxymethylchitosan (N-CMCh) is a polyelectrolite with negative charge formed by the carboxymethylation of Chitosan. The derivatization is due to soluble gel with imino groups reduced with sodium borohidrate. Then a range of N-CMChs is generated containing acethyl, carboxymethyl and free amino groups controlled according to the proportions of chitosan and glioxylic acid. To use this polymer in industrial applications, the macromolecular behaviour in solution need to be understood. In this work a sample of N-CMCh was obtained, starting from 5 g of chitosan to achieve a degree of substitution of 20.9 %. The samples were analysed by HPSEC-MALLS to verify the molecular mass distribution. The intrinsic viscosity was determined at 25o C, using a range of concentrations from 0.02 up to 0.1% (m/v), and using as salts solvent NaCl and KCl at 0.1 M. The data show that the salt can generate differences in the viscous behaviour, probably due the conformational change of the molecule con...
International Journal of Biological Macromolecules, 2015
Hydrolysis of xyloglucan from Tamarindus indica and Hymenaea courbaril seeds with endoglucanase (... more Hydrolysis of xyloglucan from Tamarindus indica and Hymenaea courbaril seeds with endoglucanase (EGII), which randomly breaks the (1→4)-linked β-glycosidic bonds of the polymer chain, was monitored in real time using time-dependent viscometry analysis (TDV). For both samples there was a decrease in the intrinsic viscosity ([η]), viscosity average molar mass (Mv), radius de gyration (Rg) and persistence length (Lp) immediately after the addition of the enzyme. It was observed the formation of oligosaccharides and oligomers composed of ∼2 units, up to 140min. Galactose-containing side chains two positions away from the non-substituted glucose, modulated the action of EGII, and the complete hydrolysis of the XG oligomers occurred after 24h. The results demonstrate for the first time the real-time degradation of xyloglucan as well the macromolecular and oligosaccharide composition during the EGII hydrolysis process.
ABSTRACT n the present work, bacterial cellulose nanocrystals (BCN) were prepared with three dist... more ABSTRACT n the present work, bacterial cellulose nanocrystals (BCN) were prepared with three distinct sulfate contents, namely 0, 0.42 and 0.65 % OSO3 −, by using HCl (BCN-HCl), a mixture of HCl and H2SO4 (BCN-HCl/H2SO4) and H2SO4 (BCN-H2SO4) as hydrolytic media, respectively. BCN were characterized by means of elemental analysis, X-ray diffraction, atomic force microscopy (AFM) and zeta potential measurements. All BCN samples had crystallinity indices of about 82 %, about 10 % higher than the original BC. The zeta potential values determined for BCN-HCl, BCN-HCl/H2SO4 and BCN-H2SO4 amounted to −(5 ± 1), −(40 ± 1) and −(46 ± 1) mV, respectively. The assembly between BCN-HCl, BCN-HCl/H2SO4 or BCN-H2SO4 and XG extracted from Tamarindus indica seeds was investigated by means of Freundlich isotherms, AFM, contact angle measurements, dynamic light scattering, ellipsometry and quartz crystal microbalance measurements. The adsorption experiments suggest that sulfate substitution on BCN surface as low as 0.65 % OSO3 − impairs the original interaction with XG, thereby generating unstable layers with subsequent desorption. In contrast, the 0.42 % OSO3 − samples presented favorable interactions with XG and exhibited highly improved colloidal stability compared to 0 % OSO3 − samples. Films of XG adsorbed onto BCN with 0.42 % OSO3 − were stable, homogeneous, and had low roughness and thickness. This is the first report showing that sulfate content on BCN surface can be tailored to promote high colloidal stability and sufficient interaction with XG.
The curcumin (CUR)-loaded binary hydrogel was formulated using xanthan and galactomannan from Sch... more The curcumin (CUR)-loaded binary hydrogel was formulated using xanthan and galactomannan from Schizolobium parahybae (guapuruvu). The binary hydrogels presented gel characteristics, stable pH values and mechanical stress resistance even after 45 days of heat exposure (45 °C). The CUR-loaded hydrogel content was 98.6% for XGMC (xanthan and galactomannan with CUR-microemulsion) after the stability test. The in vitro cytotoxicity analysis suggested non-cutaneous membrane irritation, and the in vitro skin permeation analysis indicated 2.15 to 2.50 μg mL(-1) CUR at the stratum corneum, epidermal and dermal levels. The XGEC (xanthan and galactomannan with CUR solubilized in ethanol) and XGMC hydrogels presented 76.8 and 63.2% inhibition of topical inflammation, respectively. Chemical stability and non-cytotoxicity analysis confirm the safety of prolonged exposure of the skin during the topical treatment, offering long-lasting XGEC and XGMC action.
A novel wound-dressing biodevice, sensitive to lysozyme, an enzyme commonly found at infected ski... more A novel wound-dressing biodevice, sensitive to lysozyme, an enzyme commonly found at infected skin wounds, was assembled by the layer-by-layer deposition of nanopolymeric chitosan and alginate films onto oxidized bacterial cellulose membranes incorporated with epidermal growth factor (EGF). Distinct EGF release profiles were obtained according to specific stimuli caused by infection. In in vitro conditions simulating noninfected wounds, the EGF rate and burst release effect were reduced by three deposited layers (Mt /M∞ of 0.25 at 3 h) in a process dependent on the porosity of the compact chitosan-alginate complex. The importance of the organized structure was revealed when an infected wound was simulated by adding lysozyme to the release medium, thus inducing the formation of a loosely polyelectrolyte architecture that caused rapid EGF diffusion (Mt /M∞ of 0.75 at 30 min). The results indicate that the nanopolymeric layers were capable of slowly releasing EGF as required for normal wound repair and rapidly undergoing architectural transitions that allow the diffusion of massive amounts of drug to enhance the process of re-epithelialization. In summary, the proposed system comprises the roles of both wound dressing and local delivery mechanism to recognize infections and respond with a burst of EGF release.
Litchi chinensis has been traditionally used in folk medicine to treat several ailments. In this ... more Litchi chinensis has been traditionally used in folk medicine to treat several ailments. In this study, we investigated the chemical composition, antioxidant and antinociceptive activity of L. chinensis leaves. The antioxidant capacity of the extract, fraction and compounds was evaluated using the 1,1-diphenyl-picrylhydrazyl (DPPH) and 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays, and the liposome model with peroxyl radicals generated by 2,2'-azobis (2-amidinopropane) dihydrochloride radical. The pharmacological models of acute nociception used in mice were: writhing test with acetic acid (AA), hotplate (HP), glutamate (GLU), capsaicin (CP) and formalin (FM) tests. The main compounds isolated were procyanidin A2 (PA2), procyanidin B2 (PB2) and (-)-epicatechin. The biochemical features of the crude extracts and their ethyl acetate fraction (EtOAcFR) presented high antioxidant activity, and the antioxidant activity of PA2 and PB2 was remarkably high, with DPPH and ABTS. The crude methanol extract (MeOHEXTR), EtOAcFR and PB2 were effective in reducing nociception in FM and HP models. MeOHEXTR and EtOAcFR treatments also reduced pain induced by GLU and AA. In the CP model, only EtOAcFR and PB2 were effective. The results demonstrate the antinociceptive and antioxidant of MeOHEXTR, EtOAcFR and PB2.
The phase diagram of mixtures of xyloglucan (XG) and amylopectin (AMP) in aqueous solution is pre... more The phase diagram of mixtures of xyloglucan (XG) and amylopectin (AMP) in aqueous solution is presented. Water-in-water emulsions prepared from mixtures in the two phase regime were studied in detail and the interfacial tension was determined. It is shown that the emulsions can be stabilized by addition of β-lactoglobulin microgels (βLGm), but only at pH≤5.0. Excess βLGm entered preferentially the AMP phase at pH>5.0 and the XG phase at lower pH. The inversion was caused by adsorption of XG onto βLGm that started below pH 5.5. It is shown that modification of the surface of particles by coating with polysaccharides is a potential lever to control stabilization of water-in-water emulsions.
... Hymenaea courbaril (Jatobá) seeds. RA Freitas b , c , d , S. Martin b , d , RC Paula a , JPA ... more ... Hymenaea courbaril (Jatobá) seeds. RA Freitas b , c , d , S. Martin b , d , RC Paula a , JPA Feitosa a and M. -R. Sierakowski Corresponding Author Contact Information , E-mail The Corresponding Author , d. a Departamento de ...
A three-dimensional layer-by-layer (LbL) structure composed by xanthan and galactomannan biopolym... more A three-dimensional layer-by-layer (LbL) structure composed by xanthan and galactomannan biopolymers over dioctadecyldimethylammonium bromide (DODAB) liposome template was proposed and characterized for protein drug delivery. The polymers and the surfactant interaction were sufficiently strong to create a LbL structure up to 8 layers, evaluated using quartz crystal microbalance (QCM) and zeta potential analysis. The polymer-liposome binding enthalpy was determined by isothermal titration calorimetry (ITC). The bilayer of biopolymer-coated liposomes with diameters of 165 (±15)nm, measured by dynamic light scattering (DLS), and ζ-potential of -4 (±13)mV. These bilayer-coated nanoparticles increased up to 5 times the sustained release of epidermal growth factor (EGF) at a first order rate of 0.005min(-1). This system could be useful for improving the release profile of low-stability drugs like EGF.
The N-carboxymethylchitosan (N-CMCh) is a polyelectrolite with negative charge formed by the carb... more The N-carboxymethylchitosan (N-CMCh) is a polyelectrolite with negative charge formed by the carboxymethylation of Chitosan. The derivatization is due to soluble gel with imino groups reduced with sodium borohidrate. Then a range of N-CMChs is generated containing acethyl, carboxymethyl and free amino groups controlled according to the proportions of chitosan and glioxylic acid. To use this polymer in industrial applications, the macromolecular behaviour in solution need to be understood. In this work a sample of N-CMCh was obtained, starting from 5 g of chitosan to achieve a degree of substitution of 20.9 %. The samples were analysed by HPSEC-MALLS to verify the molecular mass distribution. The intrinsic viscosity was determined at 25o C, using a range of concentrations from 0.02 up to 0.1% (m/v), and using as salts solvent NaCl and KCl at 0.1 M. The data show that the salt can generate differences in the viscous behaviour, probably due the conformational change of the molecule con...
International Journal of Biological Macromolecules, 2015
Hydrolysis of xyloglucan from Tamarindus indica and Hymenaea courbaril seeds with endoglucanase (... more Hydrolysis of xyloglucan from Tamarindus indica and Hymenaea courbaril seeds with endoglucanase (EGII), which randomly breaks the (1→4)-linked β-glycosidic bonds of the polymer chain, was monitored in real time using time-dependent viscometry analysis (TDV). For both samples there was a decrease in the intrinsic viscosity ([η]), viscosity average molar mass (Mv), radius de gyration (Rg) and persistence length (Lp) immediately after the addition of the enzyme. It was observed the formation of oligosaccharides and oligomers composed of ∼2 units, up to 140min. Galactose-containing side chains two positions away from the non-substituted glucose, modulated the action of EGII, and the complete hydrolysis of the XG oligomers occurred after 24h. The results demonstrate for the first time the real-time degradation of xyloglucan as well the macromolecular and oligosaccharide composition during the EGII hydrolysis process.
ABSTRACT n the present work, bacterial cellulose nanocrystals (BCN) were prepared with three dist... more ABSTRACT n the present work, bacterial cellulose nanocrystals (BCN) were prepared with three distinct sulfate contents, namely 0, 0.42 and 0.65 % OSO3 −, by using HCl (BCN-HCl), a mixture of HCl and H2SO4 (BCN-HCl/H2SO4) and H2SO4 (BCN-H2SO4) as hydrolytic media, respectively. BCN were characterized by means of elemental analysis, X-ray diffraction, atomic force microscopy (AFM) and zeta potential measurements. All BCN samples had crystallinity indices of about 82 %, about 10 % higher than the original BC. The zeta potential values determined for BCN-HCl, BCN-HCl/H2SO4 and BCN-H2SO4 amounted to −(5 ± 1), −(40 ± 1) and −(46 ± 1) mV, respectively. The assembly between BCN-HCl, BCN-HCl/H2SO4 or BCN-H2SO4 and XG extracted from Tamarindus indica seeds was investigated by means of Freundlich isotherms, AFM, contact angle measurements, dynamic light scattering, ellipsometry and quartz crystal microbalance measurements. The adsorption experiments suggest that sulfate substitution on BCN surface as low as 0.65 % OSO3 − impairs the original interaction with XG, thereby generating unstable layers with subsequent desorption. In contrast, the 0.42 % OSO3 − samples presented favorable interactions with XG and exhibited highly improved colloidal stability compared to 0 % OSO3 − samples. Films of XG adsorbed onto BCN with 0.42 % OSO3 − were stable, homogeneous, and had low roughness and thickness. This is the first report showing that sulfate content on BCN surface can be tailored to promote high colloidal stability and sufficient interaction with XG.
The curcumin (CUR)-loaded binary hydrogel was formulated using xanthan and galactomannan from Sch... more The curcumin (CUR)-loaded binary hydrogel was formulated using xanthan and galactomannan from Schizolobium parahybae (guapuruvu). The binary hydrogels presented gel characteristics, stable pH values and mechanical stress resistance even after 45 days of heat exposure (45 °C). The CUR-loaded hydrogel content was 98.6% for XGMC (xanthan and galactomannan with CUR-microemulsion) after the stability test. The in vitro cytotoxicity analysis suggested non-cutaneous membrane irritation, and the in vitro skin permeation analysis indicated 2.15 to 2.50 μg mL(-1) CUR at the stratum corneum, epidermal and dermal levels. The XGEC (xanthan and galactomannan with CUR solubilized in ethanol) and XGMC hydrogels presented 76.8 and 63.2% inhibition of topical inflammation, respectively. Chemical stability and non-cytotoxicity analysis confirm the safety of prolonged exposure of the skin during the topical treatment, offering long-lasting XGEC and XGMC action.
A novel wound-dressing biodevice, sensitive to lysozyme, an enzyme commonly found at infected ski... more A novel wound-dressing biodevice, sensitive to lysozyme, an enzyme commonly found at infected skin wounds, was assembled by the layer-by-layer deposition of nanopolymeric chitosan and alginate films onto oxidized bacterial cellulose membranes incorporated with epidermal growth factor (EGF). Distinct EGF release profiles were obtained according to specific stimuli caused by infection. In in vitro conditions simulating noninfected wounds, the EGF rate and burst release effect were reduced by three deposited layers (Mt /M∞ of 0.25 at 3 h) in a process dependent on the porosity of the compact chitosan-alginate complex. The importance of the organized structure was revealed when an infected wound was simulated by adding lysozyme to the release medium, thus inducing the formation of a loosely polyelectrolyte architecture that caused rapid EGF diffusion (Mt /M∞ of 0.75 at 30 min). The results indicate that the nanopolymeric layers were capable of slowly releasing EGF as required for normal wound repair and rapidly undergoing architectural transitions that allow the diffusion of massive amounts of drug to enhance the process of re-epithelialization. In summary, the proposed system comprises the roles of both wound dressing and local delivery mechanism to recognize infections and respond with a burst of EGF release.
Litchi chinensis has been traditionally used in folk medicine to treat several ailments. In this ... more Litchi chinensis has been traditionally used in folk medicine to treat several ailments. In this study, we investigated the chemical composition, antioxidant and antinociceptive activity of L. chinensis leaves. The antioxidant capacity of the extract, fraction and compounds was evaluated using the 1,1-diphenyl-picrylhydrazyl (DPPH) and 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays, and the liposome model with peroxyl radicals generated by 2,2'-azobis (2-amidinopropane) dihydrochloride radical. The pharmacological models of acute nociception used in mice were: writhing test with acetic acid (AA), hotplate (HP), glutamate (GLU), capsaicin (CP) and formalin (FM) tests. The main compounds isolated were procyanidin A2 (PA2), procyanidin B2 (PB2) and (-)-epicatechin. The biochemical features of the crude extracts and their ethyl acetate fraction (EtOAcFR) presented high antioxidant activity, and the antioxidant activity of PA2 and PB2 was remarkably high, with DPPH and ABTS. The crude methanol extract (MeOHEXTR), EtOAcFR and PB2 were effective in reducing nociception in FM and HP models. MeOHEXTR and EtOAcFR treatments also reduced pain induced by GLU and AA. In the CP model, only EtOAcFR and PB2 were effective. The results demonstrate the antinociceptive and antioxidant of MeOHEXTR, EtOAcFR and PB2.
The phase diagram of mixtures of xyloglucan (XG) and amylopectin (AMP) in aqueous solution is pre... more The phase diagram of mixtures of xyloglucan (XG) and amylopectin (AMP) in aqueous solution is presented. Water-in-water emulsions prepared from mixtures in the two phase regime were studied in detail and the interfacial tension was determined. It is shown that the emulsions can be stabilized by addition of β-lactoglobulin microgels (βLGm), but only at pH≤5.0. Excess βLGm entered preferentially the AMP phase at pH>5.0 and the XG phase at lower pH. The inversion was caused by adsorption of XG onto βLGm that started below pH 5.5. It is shown that modification of the surface of particles by coating with polysaccharides is a potential lever to control stabilization of water-in-water emulsions.
... Hymenaea courbaril (Jatobá) seeds. RA Freitas b , c , d , S. Martin b , d , RC Paula a , JPA ... more ... Hymenaea courbaril (Jatobá) seeds. RA Freitas b , c , d , S. Martin b , d , RC Paula a , JPA Feitosa a and M. -R. Sierakowski Corresponding Author Contact Information , E-mail The Corresponding Author , d. a Departamento de ...
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