Incorporation of a model protein into chitosan–bile salt microparticles

Promising Methods of Antibacterial Finishing of Textile Materials

A review article, containing information on the options, possibilities, and prospects for the development of antibacterial finishing of textile materials, is presented. A wide range of products designed to impart antibacterial, antimicrobial, and antiviral properties to textile materials is considered. The main factors determining the appropriate decision on the technological and functional choice of the protective composition are presented, including the nature of the fiber-forming polymer, the tasks that the resulting material is designed to solve, and its application options. Compositions providing the required effect of destruction of the pathogenic flora and their application technologies are described. Special attention is paid to antimicrobial agents based on silver nanoparticles. Nanoparticles of this metal have a detrimental effect on antibiotic-resistant strains of bacteria; their effectiveness is higher as compared to a number of well-known antibiotics, for example, penicillin and its analogues. Silver nanoparticles are harmless to the human body. Acting as an inhibitor, they limit the activity of the enzyme responsible for oxygen consumption by single-cell bacteria, viruses, and fungi. In this case, silver ions bind to the outer and inner proteins of the bacterial cell membranes, blocking cellular respiration and reproduction. Various options to apply microencapsulation methods for the implementation of antibacterial finishing are considered, including: phase separation, suspension crosslinking, simple and complex coacervation, spray drying, crystallization from the melt, evaporation of the solvent, co-extrusion, layering, fluidized bed spraying, deposition, emulsion and interphase polymerization, layer-by-layer electrostatic self-assembly etc. All presented technologies are at various development stages-from the laboratory stage to production tests, they all have certain advantages and disadvantages. The accelerated development and implementation of the described methods in production of textile materials is relevant and is related to the existing complex epidemiological situation in the world.

Development of Multifunctional Coating of Textile Materials Using Silver Microencapsulated Compositions

The efficiency of the method for the synthesis of silver nanoparticles using a system containing oxalic dialdehyde as a reducing agent, and polyguanidine as a stabilizer is shown. An analysis of the data of photon correlation spectroscopy characterizing the sizes of the formed particles in the Ag-polyelectrolyte system is presented. It has been established that the synthesized silver nanoparticles have a stable biocidal effect. The system of biodegradable polyelectrolytes chitosan-xanthan gum for the synthesis of the capsule shell including silver nanoparticles is selected. This will allow the formation of stable polyelectrolyte capsule shells containing oyster mushroom mycelium extract. A protocol for the synthesis of microcapsules by the method of sequential adsorption of chitosan polyelectrolytes and xanthan gum on calcium carbonate templates was developed. Silver nanoparticles are included in the capsule shell, and a biologically active drug (oyster mushroom mycelium extract) is included in the core. The technological mode of complex capsules immobilization on a textile material by the layer-by-layer method is described. The immobilization of multilayer microcapsules on a fibrous substrate is provided by a system of polyelectrolytes: positively charged chitosan and negatively charged xanthan gum. The developed multifunctional coatings make it possible to impart multifunctional properties to textile materials: antibacterial, antimycotic, high hygroscopic properties.

Co-assembly in chitosan-surfactant mixtures: thermodynamics, structures, interfacial properties and applications

In this review, different aspects characterizing chitosan-surfactant mixtures are summarized and compared. Chitosan is a bioderived cationic polysaccharide that finds wide-ranged applications in various field, e.g., medical or food industry, in which synergistic effects with surfactant can play a fundamental role. In particular, the behavior of chitosan interacting with strong and weak anionic, nonionic as well as cationic surfactants is reviewed. We put a focus on oppositely charged systems, as they exhibit the most interesting features. In that context, we discuss the thermodynamic description of the interaction and in particular the structural changes as they occur as a function of the mixed systems and external parameters. Moreover, peculiar properties of chitosan coated phospholipid vesicles are summarized. Finally, their co-assembly at interfaces is briefly reviewed. Despite the behavior of the mentioned systems might strongly differ, resulting in a high variety of properties, few general rules can be pointed out which improve the understanding of such complex systems.

Formation of liquid-crystalline structures in the bile salt-chitosan system and triggered release from lamellar phase bile salt-chitosan capsules

Nanostructured capsules comprised of the anionic bile salt, sodium taurodeoxycholate (STDC), and the biocompatible cationic polymer, chitosan, were prepared to assess their potential as novel tailored release nanomaterials. For comparison, a previously studied system, sodium dodecyl sulfate (SDS), and polydiallyldimethylammonium chloride (polyDADMAC) was also investigated. Crossed-polarizing light microscopy (CPLM) and small-angle X-ray scattering (SAXS) identified the presence of lamellar and hexagonal phase at the surfactant-polymer interface of the respective systems. The hydrophobic and electrostatic interactions between the oppositely charged components were studied by varying temperature and salt concentration, respectively, and were found to influence the liquid-crystalline nanostructure formed. The hexagonal phase persisted at high temperatures, however the lamellar phase structure was lost above ca. 45 °C. Both mesophases were found to dissociate upon addition of 4% NaCl solution. The rate of release of the model hydrophilic drug, Rhodamine B (RhB), from the lamellar phase significantly increased in response to changes in the solution conditions studied, suggesting that modulating the drug release from these bile salt-chitosan capsules is readily achieved. In contrast, release from the hexagonal phase capsules had no appreciable response to the stimuli applied. These findings provide a platform for these oppositely charged surfactant and polymer systems to function as stimuli-responsive or sustained-release drug delivery systems.

Preparation of iron oxide nanoparticles stabilized with biomolecules: experimental and mechanistic issues

Nanoparticles (NPs) with magnetic properties based on magnetite (Fe(3)O(4), MAG) modified with oleic acid (OA), chitosan (CS) and bovine serum albumin (BSA) have been prepared. A versatile method of synthesis was employed, involving two steps: (i) co-precipitation of MAG; and (ii) nanoprecipitation of macromolecules on as-formed MAG NPs. Experimental variables have been explored to determine the set of conditions that ensure suitable properties of NPs in terms of their size, functionality and magnetic properties. It was found that the presence of OA in Fe(+2)/Fe(+3) solutions yields MAG NPs with lower aggregation levels, while increasing initial amounts of OA may change the capability of NPs to disperse in aqueous or organic media by modifying the stabilization mechanism. Incorporation of CS was verified through Fourier transform IR spectroscopy. This biopolymer stabilizes NPs by electrostatic repulsions leading to stable ferrofluids and minimal fraction of recoverable solid NPs. BSA was successfully added to NP formulations, increasing their functionality and probably their biocompatibility. In this case too stable ferrofluids were obtained, where BSA acts as a polyelectrolyte. From the proposed methodology it is possible to achieve a wide range of NPs magnetically active intended for several applications. The required properties may be obtained by varying experimental conditions.

Chitosan/PLGA particles for controlled release of α-tocopherol in the GI tract via oral administration

Aim: The physiochemical properties, controlled release characteristics, stability and cellular uptake of chitosan (Chi)/poly(D,L-lactide-co-glycolide) (PGLA) and PLGA particles with entrapped α-tocopherol were investigated to understand the behavior of these nanoparticles in the GI tract. Materials & Methods: Chi/PLGA and PLGA particles stabilized by lecithin were synthesized and fully characterized for oral gastrointestinal delivery via transmission electron microscopy, dynamic light scattering, high-performance liquid chromatography and fluorescence microscopy. Results: Particle stability was pH- and system-dependent. In vitro release profiles showed a higher percentage of drug released in the intestinal domain by Chi/PLGA as opposed to the PLGA nanoparticles. Fluorescent counterparts of these particles were confirmed to associate with the surface of the intestinal villi, and penetrate deep in the endothelial lining of rabbit intestinal explants, indicating uptake. Conclusion: In vitro and ex vivo results showed that PLGA and Chi/PLGA nanoparticles were efficiently taken up by the GI tract and could be optimized to deliver αtocopherol to the intestine and improve its bioavailability.

Formulation optimization of propranolol hydrochloride microcapsules employing central composite design

A central composite design was employed to produce microcapsules of propranolol hydrochloride by o/o emulsion solvent evaporation technique using a mixture of cellulose acetate butyrate as coat material and span-80 as an emulsifier. The effect of formulation variables namely levels of cellulose acetate butyrate (X(1)) and percentage of Span-80 (X(2)) on encapsulation efficiency (Y(1)), drug release at the end of 1.5 h (Y(2)), 4 h (Y(3)), 8 h (Y(4)), 14 h (Y(5)), and 24 h (Y(6)) were evaluated using the F test. Mathematical models containing only the significant terms were generated for each response parameter using multiple linear regression analysis and analysis of variance. Both the formulation variables exerted a significant influence (P <0.05) on Y(1) whereas the cellulose acetate butyrate level emerged as the lone factor which significantly influenced the other response parameters. Numerical optimization using desirability approach was employed to develop an optimized formulation by setting constraints on the dependent and independent variables. The experimental values of Y(1), Y(2), Y(3), Y(4), Y(5), and Y(6) for the optimized formulation was found to be 92.86+/-1.56% w/w, 29.58+/-1.22%, 48.56+/-2.56%, 60.85+/-2.35%, 76.23+/-3.16% and 95.12+/-2.41%, respectively which were in close agreement with those predicted by the mathematical models. The drug release from microcapsules followed first order kinetics and was characterized by Higuchi diffusion model. The optimized microcapsule formulation developed was found to comply with the USP drug release test-1 for extended release propranolol hydrochloride capsules.

Encapsulation of adenoviral vectors into chitosan–bile salt microparticles for mucosal vaccination

The objective of this study is the incorporation of adenoviral vectors into a microparticulate system adequate for mucosal delivery. Microencapsulation of the vectors was accomplished by ionotropic coacervation of chitosan, using bile salts as counter-anion. The process was optimized in order to promote high encapsulation efficiency, with a minimal loss of viral infectivity. The maintenance of sterility during all the encapsulation procedure was also taken into account. The principle relies on the simple addition of a solution containing adenoviral vectors to a solution of neutralized chitosan, under stirring. Some surfactants were added to the chitosan solution, to improve the efficiency of this process, such as Tween 80, and Pluronic F68 at 1% (w/v). Encapsulation efficiency higher than 84% was achieved with formulations containing sodium deoxycholate as counter-anion and Pluronic F68 as dispersant agent. The infectivity of the adenoviral vectors incorporated into microparticles was assessed by release assays in PBS and by direct inoculation in 293 and Caco-2 cells. The release in aqueous media was negligible but, when in contact with monolayers of the cells, an effective release of bioactive adenovirus was obtained. Our work shows that encapsulation in microparticles, not only appear to protect the adenovirus from the external medium, namely from low pH, but can also delay their release that is fully dependent on cell contact, an advantage for mucosal vaccination purposes. The formulations developed are able to maintain AdV infectivity and permit a delayed release of the bioactives that is promoted by digestion in situ of the microparticles by the cell monolayers. The onset of delivery is, that way, host-controlled. In view of these results, these formulations showed good properties for mucosal adenovirus delivery.