Aplicação de nanopartículas de quitosana com potencial de adjuvante na produção de soro contra o venneno do escorpião Tityus serrulatus

In Brazil, several species of scorpions are known to cause accidents which can lead to death, which are mainly belonging to the genus Tityus. The scorpion Tityus serrulatus is the main responsible for more severe cases. Anti-scorpion serums are routinely produced by various institutions, despite their effectiveness, quality and action depends on how quickly treatment is started. Studies have been developed in the search for appropriate technologies to encapsulate and release recombinant or natives proteins capable of inducing antibody production. In this context, chitosan copolymer which can be obtained from the partial deacetylation of chitin or in some microorganisms and it is biocompatible and biodegradable has been widely used for this purpose. This study aimed to search for a system release from chitosan nanoparticles for peptide / protein of the venom of the scorpion T. serrulatus, able to provide a new model of immunization in animals, in order to obtain a potential novel polyclonal serum, anti-venom T. serrulatus. The chitosan nanoparticles were prepared by ionic gelation with polyanion tripolyphosphate (TPP). After standardizing the concentrations of TPP and chitosan was evaluated the efficiency of incorporation of bovine serum albumin (BSA) and scorpion venom, showed particle size compatible with the intended purpose. The particles showed adequate size around 200nm. The crosslinking was confirmed by absorption spectroscopy in the infrared. After verified the high encapsulation efficiency (EE) for acid bicinconínico method (BCA) protein assay and the particle size distribution, the success of the technique was proven and the potential for in vivo application of nanoparticles. The experimental animals were vaccinated and the antibodies measured by ELISA

Eletrofiação e caracterização de membranas biopoliméricas a base de quitosana extraídas dos exoesqueletos de crustáceos

Chitin and chitosan are nontoxic, biodegradable and biocompatible polymers produced by renewable natural sources with applications in diverse areas such as: agriculture, textile, pharmaceutical, cosmetics and biomaterials, such as gels, films and other polymeric membranes. Both have attracted greater interest of scientists and researchers as functional polymeric materials. In this context, the objective of this study was to take advantage of the waste of shrimp (Litopenaeus vannamei and Aristeus antennatus) and crabs (Ucides cordatus) from fairs, beach huts and restaurant in Natal/RN for the extraction of chitin and chitosan for the production of membranes by electrospinning process. The extraction was made through demineralization, deproteinization, deodorization and deacetylation. Morphological analyzes (SEM and XRD), Thermal analysis (TG and DTG), Spectroscopy in the Region of the Infrared with Transformed of Fourier (FTIR) analysis Calorimetry Differential Scanning (DSC) and mechanical tests for traction were performed. In (XRD) the semicrystalline structure of chitosan can be verified while the chitin had higher crystallinity. In the thermal analysis showed a dehydration process followed by decomposition, with similar behavior of carbonized material. Chitosan showed temperature of maximum degradation lower than chitin. In the analysis by Differential Scanning Calorimetry (DSC) the curves were coherent to the thermal events of the chitosan membranes. The results obtained with (DD) for chitosan extracted from Litopenaeus vannamei and Aristeus antennatus shrimp were (80.36 and 71.00%) and Ucides cordatus crabs was 74.65%. It can be observed that, with 70:30 solutions (v/v) (TFA/DCM), 60 and 90% CH3COOH, occurred better facilitate the formation of membranes, while 100:00 (v/v) (TFA/DCM) had formation of agglomerates. In relation to the monofilaments diameters of the chitosan membranes, it was noted that the capillary-collector distance of 10 cm and tensions of 25 and 30 kV contributed to the reduction of the diameters of membranes. It was found that the Young s modulus decreases with increasing concentration of chitosan in the membranes. 90% CH3COOH contributed to the increase in the deformation resulting in more flexible material. The membranes with 5% chitosan 70:30 (v/v) (TFA/DCM) had higher tensile strength

Eficácia do bochecho de quitosana a 0,4% sobre o biofilme e bactérias orais

The purpose of this study was evaluate the effectiveness of the chitosan at 0.4 with high molecular weight and high deacetylation degree mouthrinse over the total decrease of the streptococci, Streptococcus mutans, lactobaci/li and over the perceptible bacterial film and gingival bleeding indices. For that, a total of 68 healthy students between 11 and 13 years old, not allergic to crustacean and not users of antibiotics or antimicrobial agent for the last three months or during the treatment, was selected. From those, thirty two individuaIs used the mouthrinse test, and thirty six, the control one. The participants rinsed 10 mL of the solutions twice a day, one during the moming (which was supervised), and another one during the aftemoon (which was not supervised), for fifteen days. The saliva collect for the microbiological analysis, as well as the perceptible bacterial film and gingival bleeding indices check, were made before the use ofthe mouthrinses (base line), immediately after the last mouthrinse on the day (zero time) and fifteen days after (fifteen time). These data were collected at school and the saliva was carried inside the ice to the laboratory. The samples were diluted, and 0.1 mL ofthe 10 -1 dilution was seeded in Rogosa SL agar, for further analysis of the total of lactobaci/lus~ 0.1 mL of the 10-4 dilution in Mitis Salivarius with bacitracin, for S. mutans analysis; and 0.1 mL of the 10-6 dilution in Mitis Salivarius for the analysis ofthe total of streptococcus. The Rogosa SL agar plates were incubated in aerobic at 37°C for 72 hours and the MSB and the MS were incubated in anaerobic in Gaspak@ jars at 37°C for 48 hours for further count ofColonies Former Units (CFUs). The assay was made in duplicate for each bacterial group analyzed. The number of CFUs transformed in LOGlO was analyzed according to the following tests: ANOV A, t of Paired and Not Paired Student, Friedman, Man-Whitney and square-qui test. On the base line, alI the variables analyzed were similar on both tested groups. On both groups, for the total of streptococcus there was no significant difference along the time and for S. mutans there was a statistic significant increase of the CFUs from the base line to the zero time. For the total of lactobaccilus there was no significant difference on the test group along the time, and on the control there was a significant increase ofthe CFUs ITom the base line to the zero time. For both groups, there was significant decrease ofthe perceptible bacterial film index along the time, and that can be explained by the mechanic effect of the mouthrinse over the bacterial film and by the participation of the students on the research which could have motivated him to a better toothbrushing (Hawthome effect). The gingival bleeding index also showed a decrease along the time, even though it was not significant. Therefore, the conclusion of this study was that the chitosan at 0.4 % mouthrinse was not effective on the CFUs reduction of the three bacterial groups analyzed, as well as on the reduction of the perceptible bacterial film and gingival bleeding indices

Alquilação redutiva da quitosana a partir do glutaraldeído e 3-amino-1-pr

Chitosan derivatives were prepared by reductive alkylation using glutaraldehyde and 3-amino-1-propanol. The reducing agent used was the sodium borohydride. Tests of solubility, stability and viscosity were performed in order to evaluate these parameters effects in the reaction conditions (molar ratio of the reactants and presence of nitrogen in the reaction system). The molecular structure of commercial chitosan was determined by infrared (IR) and hydrogen nuclear magnetic resonance spectroscopy (1H NMR). The intrinsic viscosity and average molecular weight of the chitosan were determined by viscosimetry in 0.3 M acetic acid aqueous solution 0.2 M sodium acetate at 25 ºC. The derivatives of chitosan soluble in aqueous acidic medium were characterized by 1H NMR. The rheological behavior of the chitosan and of the derivative of chitosan (sample QV), which presented the largest viscosity, were studied as a function of polymer concentration, temperature and ionic strength of the medium. The results of characterization of the commercial chitosan (the degree of deacetylation obtained equal 78.45 %) used in this work confirmed a sample of low molar weight (Mv = 3.57 x 104 g/mol) and low viscosity (intrinsic viscosity = 213.56 mL/g). The chemical modification of the chitosan resulted in derivatives with thickening action. The spectra of 1H NMR of the soluble derivatives in acid aqueous medium suggested the presence of hydrophobic groups grafted into chitosan in function of the chemical modification. The solubility of the derivatives of chitosan in 0.25 M acetic acid aqueous solution decreased with increase of the molar ratio of the glutaraldehyde and 3-amino-1-propanol in relation to the chitosan. The presence of nitrogen and larger amount of reducing agent in reaction system contributed to the increase of the solubility, the stability and the viscosity of the systems. The viscosity of the polymeric suspensions in function of the shear rate increased significantly with polymer concentration, suggesting the formation of strong intermolecular associations. The chitosan presented pseudoplastic behavior with the increase in polymer concentration at a low shear rate. The derivative QV presented pseudoplastic behavior at all concentrations used and in a large range of shear rate. The viscosity of chitosan in solution decreased with an increase of the temperature and with the presence of salt. However, there was an increase of the viscosity of the chitosan solution at higher temperature (65 ºC) and ionic strength of the medium which were promoted by hydrophobic associating of the acetamide groups. The solutions of the chitosan derivatives (sample QV) were significantly more viscous than chitosan solution and showed higher thermal stability in the presence of salt as a function of the hydrophobic groups grafted into chitosan backbone

Estudos de adsorção de tetraciclina e cromoglicato em partículas de quitosana

Among the polymers that stand out most in recent decades, chitosan, a biopolymer with physico-chemical and biological promising properties has been the subject of a broad field of research. Chitosan comes as a great choice in the field of adsorption, due to their adsorbents properties, low cost and abundance. The presence of amino groups in its chain govern the majority of their properties and define which application a sample of chitosan may be used, so it is essential to determine their average degree of deacetylation. In this work we developed kinetic and equilibrium studies to monitor and characterize the adsorption process of two drugs, tetracycline hydrochloride and sodium cromoglycate, in chitosan particles. Kinetic models and the adsorption isotherms were applied to the experimental data. For both studies, the zeta potential analyzes were also performed. The adsorption of each drug showed distinct aspects. Through the studies developed in this work was possible to describe a kinetic model for the adsorption of tetracycline on chitosan particles, thus demonstrating that it can be described by two kinetics of adsorption, one for protonated tetracycline and another one for unprotonated tetracycline. In the adsorption of sodium cromoglycate on chitosan particles, equilibrium studies were developed at different temperatures, allowing the determination of thermodynamic parameters

Estudos de adsorção de tetraciclina em partículas de quitosana

Due to its physico-chemical and biological properties, related to the abundance and low cost of raw material, chitosan has been recognized as a material of wide application in various fields, such as in drug delivery systems. Many of these properties are associated with the presence of amino groups in its polymer chain. A proper determination of these amino groups is very important, in order to properly specify if a given chitosan sample can be used in a particular application. Thus, in this work, initially, a comparison between the determination of the deacetylation degree by conductometry and elemental analysis was carried out using a detailed analysis of error propagation. It was shown that the conductometric analysis resulted in a simple and safe method for the determining the degree of deacetylation of chitosan. Subsequently, experiments were performed to monitor and characterize the adsorption of tetracycline on chitosan particles through kinetic and equilibrium studies. The main models of kinetics and adsorption isotherms, widely used to describe the adsorption on wastewater treatment systems and the drug loading, were used to treat the experimental data. Firstly, it was shown that an apparent linear t/q(t) × t relationship did not imply in a pseudo-second-order adsorption kinetics, differently of what has been repeatedly reported in the literature. It was found that this misinterpretation can be avoided by using non-linear regression. Finally, the adsorption of tetracycline on chitosan particles was analyzed using insights obtained from theoretical analysis, and the parameters generated were used to analyze the kinetics of adsorption, the isotherm of adsorption and to ropose a mechanism of adsorption

Estudos das interações de quitosana/CTAB/C12E8

Surfactant-polymer interactions are widely used when required rheological properties for specific applications, such as the production of fluids for oil exploration. Studies of the interactions of chitosan with cationic surfactants has attracted attention by being able to cause changes in rheological parameters of the systems making room for new applications. The commercial chitosan represents an interesting alternative to these systems, since it is obtained from partial deacetylation of chitin: the residues sites acetylated can then be used for the polymer-surfactant interactions. Alkyl ethoxylated surfactants can be used in this system, since these non-ionic surfactants can interact with hydrophobic sites of chitosan, modifying the rheology of solutions or emulsions resultants, which depends on the relaxation phenomenon occurring in these systems. In this work, first, inverse emulsions were prepared from chitosan solution as the dispersed phase and cyclohexane as the continuous phase were, using CTAB as a surfactant. The rheological analysis of these emulsions showed pronounced pseudoplastic behavior. This behavior was attributed to interaction of "loops" of chitosan chains. Creep tests were also performed and gave further support to these discussions. Subsequently, in order to obtain more information about the interaction of chitosan with non-ionic surfactants, solutions of chitosan were mixed with C12E8 and and carried out rheological analysis and dynamic light scattering. The systems showed marked pseudoplastic behavior, which became less evident when the concentration of surfactant was increased. Arrhenius and KWW equations were used to obtain parameters of the apparent activation energy and relaxation rate distribution, respectively, to which were connected to the content of surfactant and temperature used in this work