Co-assembly of chitosan and phospholipids into hybrid hydrogels

Novel hybrid hydrogels were formed by adding chitosan (Ch) to phospholipids (P) self-assembled particles in lactic acid. The effect of the phospholipid concentration on the hydrogel properties was investigated and was observed to affect the rate of hydrogel formation and viscoelastic properties. A lower concentration of phospholipids (0.5% wt/v) in the mixture, facilitates faster network formation as observed by Dynamic Light Scattering, with lower elastic modulus than the hydrogels formed with higher phospholipid content. The nano-porous structure of Ch/P hydrogels, with a diameter of 260±20 nm, as observed by cryo-scanning electron microscopy, facilitated the penetration of water and swelling. Cell studies revealed suitable biocompatibility of the Ch/P hydrogels that can be used within life sciences applications

Waterborne Electrospinning of α-Lactalbumin Generates Tunable and Biocompatible Nanofibers for Drug Delivery

This is the author accepted manuscript. The final version is available from the American Chemical Society via the DOI in this recordProtein-based drug carriers are an interesting alternative to traditional polymeric drug delivery systems due to their intrinsic biocompatibility and biodegradability. Electrospinning of neat proteins holds advantages over electrospinning of protein mixtures, e.g., whey isolates, such as better control of the physicochemical and biological function of the resulting nanofiber-based system. In this study, we explore electrospinning of the isolated milk protein α-lactalbumin (ALA), which is a whey protein with important nutritional and pharmacological properties. Via waterborne electrospinning of ALA with a minimum amount of poly(ethylene oxide) (PEO) as a cospininng polymer, nanofibers of high protein content were successfully produced (up to 84% (w/w)). We demonstrate the ability to produce ALA-based nanofibers with a high degree of tunability in terms of size, stability in water, and mechanical properties. The nanofibers displayed excellent biocompatibility in vitro as the viability of cultured TR146 human buccal epithelium and NIH 3T3 murine fibroblast cells was not influenced by exposure to ALA-based nanofibers. ALA-based nanofibers were loaded with up to 6% (w/w) ampicilin, and the nanofibers were capable of maintaining the activity of the antibiotic after electrospinning and cross-linking. Using such a property of the material, we demonstrate that ampicillin-loaded nanofibers successfully inhibit the growth of Gram-negative bacteria in vitro. Importantly, after treatment with ampicillin-loaded nanofibers, no bacterial regrowth was observed, which indicates that this treatment may clear eventual persisters to ampicillin. Finally, the structural properties of the native functional protein were maintained after release of ALA from the nanofibers. This promotes our platform, not only as a sustainable protein-based drug delivery system, but also as an innovative solid form of ALA for food and pharmaceutical applications.Villum FoundationDanish Council for Independent Research; Technology and ProductionRoyal SocietyMedical Research Council (MRC)Wellcome Trus

Thermoreversible gels of hydrophobically modified hydroxyethyl cellulose cross-linked by amylose

Aqueous mixtures of hydrophobically modified hydroxyethyl cellulose (HMHEC) or unmodified hydroxyethyl cellulose (HEC), with amylose (AM) or potato amylopectin (PAP), have been investigated by rheology, turbidity, and H-1 NMR measurements. It is concluded that the AM molecules cross-link HMHEC chains by forming helical inclusion complexes with the hydrophobic side chains of HMHEC, leading to thermoreversible, elastic, and thixotropic gels at ambient temperatures. The complexation ability, the setting-melting temperature of the AM-HMHEC complexes, the strength of the association, and the viscoelastic behavior of the gels vary with the polymer concentrations, the pH, and the preparation method. AM-HMHEC complexes were obtained at a pH range of 7-12.5, but a maximum storage modulus was observed at pH approximate to 10. The AM-HMHEC complexation is modified or completely abolished by the addition of surfactant. A weak synergistic interaction was found for mixtures of PAP with HNIHEC. No complexation was observed between HEC and either AM or PAP

Electrostatic self-assembly of polysaccharides into nanofibers

In this study, the anionic polysaccharide Xanthan gum (X) was mixed with positively charged Chitosan oligomers (ChO), and used as building blocks, to generate novel nanofibers by electrostatic self-assembly in aqueous conditions. Different concentrations, ionic strength and order of mixing of both components were tested and observed to affect the diameter, which ranged from 100 to 500 nm, and morphology of the self-assembled nanofibers. The release of diclofenac, as model drug, from self-assembled xanthan-chitosan nanofibers was demonstrated, suggesting that these nanostructures can be used in applications within life sciences such as drug delivery

Generation of molecular recognition sites in electrospun polymer nanofibers via molecular imprinting

A simple method for the formation of molecular recognition sites in polymer nanofibers was developed. Electrospun nanofibers were prepared from a Solution mixture of poly(ethylene terephthalate) (PET) and polyallylamine in the presence of a template molecule, 2,4-dichlorophenoxyacetic acid (2,4-D). The polyamine was used to provide functional groups that interact with the template during the electrospinning process, and PET acted as a major supporting matrix to ensure easy fiber formation and to minimize the conformational change of the polymers when the nanofibers were subjected to different solvent treatments. When the template was removed by solvent extraction, imprinted binding sites were left in the nanofiber materials that are capable of selectively rebinding the target molecule. The molecularly imprinted nanofibers were characterized by SEM, FT-IR, and radioligand binding analysis

Development of electrosprayed mucoadhesive chitosan microparticles

The efficacy of chitosan (CS) to be used as drug delivery carrier has previously been reported. However, limited work has been pursued to produce stable and mucoadhesive CS electrosprayed particles for oral drug delivery, which is the aim of this study. Various CS types with different molecular weight (MW), degree of deacetylation (DD), and degree of polymerization (DP) were assessed. In addition, the effect of the solvent composition was also investigated. Results showed that stable CS electrosprayed particles can be produced by dissolving 3% w/v of low MW CS in mixtures of aqueous acetic acid and ethanol (50/50% v/v). The stable CS particles displayed diameters of approximately 1 μm as determined by dynamic light scattering. The zeta potential of these particles was found to be approximately 40 mV confirming the mucoadhesion properties of these CS electrosprayed particles and its potential to be used as drug delivery carrier

Nicotine Fast Dissolving Films Made of Maltodextrins: A Feasibility Study

This work aimed to develop a fast-dissolving film made of low dextrose equivalent maltodextrins (MDX) containing nicotine hydrogen tartrate salt (NHT). Particular attention was given to the selection of the suitable taste-masking agent (TMA) and the characterisation of the ductility and flexibility under different mechanical stresses. MDX with two different dextrose equivalents (DEs), namely DE 6 and DE 12, were selected in order to evaluate the effect of polymer molecular weight on film tensile properties. The bitterness and astringency intensity of NHT and the suppression effect of several TMA were evaluated by a Taste-Sensing System. The films were characterised in term of NHT content, tensile properties, disintegration time and drug dissolution test. As expected, placebo films made of MDX DE 6 appeared stiffer and less ductile than film prepared using MDX DE 12. The films disintegrated within 10 s. Among the tested TMA, the milk and mint flavours resulted particularly suitable to mask the taste of NHT. The addition of NHT and taste-masking agents affected film tensile properties; however, the effect of the addition of these components can be counterweighted by modulating the glycerine content and/or the MDX molecular weight. The feasibility of NHT loaded fast-dissolving films was demonstrated

Homewear in Brazil: evolution from 1976 to present

The traditional bride trousseau (homewear) was composed of bedding, table and bath textiles and household utensils that were necessary for her married life. Social changes and technological advances provided a new perspective and proportion for homewear textile sector. This study aimed to analyze the evolution of household linen (bedding, table and bath), from 1976 to 2019, in Brazil, related to composition of materials. Literature and magazines of this area were analyzed, notably Casa Vogue Brasil (“Vogue Home Brazil”) and Casa Claudia (“Claudia Home”) magazines. It concluded that the main employed material is cotton, followed in lesser extent by blends (notably cotton and polyester). The classic patterns predominate, especially the flat fabrics, ornamented with embroidery and classic design of flower and geometric prints, white and soft colors (clear beige, clear gray, etc.). These products represent the majority of sales in the domestic, but they could be non-competitive at the foreign market considering the price in relation to commodities from Asia and also lacking the necessary differentiation to meet these target publicsThe authors gratefully acknowledge the funding by CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (”Brazilian Federal Agency for Support and Evaluation of Graduate Education”) and and FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais (“Minas Gerais State Research Support Foundation”)