Search Results (8)

The substitution of synthetic food dyes with natural colorants continues to be assiduously pursued. The current list of natural carotenoid colorants consists of plant-derived annatto (bixin and norbixin), paprika (capsanthin and capsorubin), saffron (crocin), tomato and gac fruit lycopene, marigold lutein, and red palm oil (α- and β-carotene), along with microalgal Dunaliella β-carotene and Haematococcus astaxanthin and fungal Blakeslea trispora β-carotene and lycopene. Potential microalgal sources are being sought, especially in relation to lutein, for which commercial plant sources are lacking. Research efforts, manifested in numerous reviews and research papers published in the last decade, have been directed to green extraction, microencapsulation/nanoencapsulation, and valorization of processing by-products. Extraction is shifting from conventional extraction with organic solvents to supercritical CO₂ extraction and different types of assisted extraction. Initially intended for the stabilization of the highly degradable carotenoids, additional benefits of encapsulation have been demonstrated, especially the improvement of carotenoid solubility and bioavailability. Instead of searching for new higher plant sources, enormous effort has been directed to the utilization of by-products of the fruit and vegetable processing industry, with the application of biorefinery and circular economy concepts. Amidst enormous research activities, however, the gap between research and industrial implementation remains wide. Full article

The current growing attractiveness of natural dyes around the world is a consequence of the increasing rejection of synthetic dyes whose use is increasingly criticized. The great interest in natural pigments from herbal origin such as cyanidin 3-O-glucoside (C3G) is due to their biological properties and their health benefits. However, the chemical instability of C3G during processing and storage and its low bioavailability limits its food application. Nanoencapsulation technology using appropriate nanocarriers is revolutionizing the use of anthocyanin, including C3G. Owing to the chemical stability and functional benefits that this new nanotechnology provides to the latter, its industrial application is now extending to the pharmaceutical and cosmetic fields. This review focuses on the various nanoencapsulation techniques used and the chemical and biological benefits induced to C3G. Full article

Traditionally synthetic textile dyes are hazardous and toxic compounds devoid of any biological activity. As nanoencapsulation of yellow everzol textile dye with chitosan has been shown to produce biocompatible nanoparticles which were still capable of dyeing textiles, this work aims to further characterize the biocompatibility of yellow everzol nanoparticles (NPs) and to ascertain if the produced nanoencapsulated dyes possess any biological activity against various skin pathogens in vitro assays and in a cell infection model. The results showed that the NPs had no deleterious effects on the HaCat cells’ metabolism and cell wall, contrary to the high toxicity of the dye. The biological activity evaluation showed that NPs had a significant antimicrobial activity, with low MICs (0.5–2 mg/mL) and MBCs (1–3 mg/mL) being registered. Additionally, NPs inhibited biofilm formation of all tested microorganisms (inhibitions between 30 and 87%) and biofilm quorum sensing. Lastly, the dye NPs were effective in managing MRSA infection of HaCat cells as they significantly reduced intracellular and extracellular bacterial counts. Full article

In recent years bioactive textiles have risen to the forefront of consumers perception due to their potential protection against virus, fungi and bacteria. However, traditional textile staining is an eco-damaging process that and current methods of textile functionalization are expensive, complicated and with great environmental impact. With that in mind, this work sought to show a possible solution for this problematic through the usage of a novel one step textile dyeing and functionalization method based upon nanoencapsulated textile dyes (NTDs). To do so navy blue everzol NTDs were produced with chitosan, cotton dyed, characterized through FTIR and SEM and biological potential evaluated through biocompatibility screening and antimicrobial activity against skin pathogens. The data obtained showed that NTDs effectively dyed the target textile through a coating of the cotton fibre and that NTDs formed hydrogen bonds with the cellulose fibre via electrostatic interactions of the chitosan amino groups with cotton sulphate groups. From a biocompatibility perspective NTDs dyed cotton had no deleterious effects upon a skin cell line, as it promoted cellular metabolism of HaCat cells, while traditionally died cotton reduced it by 10%. Last but not least, NTDs dyed cotton showed significant antimicrobial activity as it reduced viable counts of MRSA, MSSA and A. baumannii between 1 and 2 log of CFU while traditional dyed cotton had no antimicrobial activity. Considering these results the novel method proposed shows is a viable and ecological alternative for the development of antimicrobial textiles with potential biomedical applications. Full article

The growing interest in the appearance and color of teeth has led to the emergence of a wide range of teeth whitening methods, both in dental offices and in patients’ homes. Concerns about the possible side effects or toxic effects of peroxide-based whitening gels leads to the identification of alternative whitening methods, based on natural compounds with mild action on tooth enamel and remineralizing effect. In this context, this study describes the preparation and in vitro analysis of whitening gels based on natural active agents—bromelain, quince and whey—using organic (polyacrylate, polyethylene glycol) and/or inorganic (silicate) excipients. Five natural products gels were prepared, containing bromelain extract, quince extract and whey, in various proportions. Two supplementary gels, one containing Lubrizol and another containing SiO₂, were prepared. All gels were submitted for multiple in vitro analysis such as: SDS-PAGE analysis, UV-vis and FTIR spectroscopy, SEM microscopy, antibacterial activity on Streptococcus mutans ATCC 25175, Porphyromonas gingivalis ATCC 33277, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923. The quince extract sample was the only one which completely discolored the blue dye on SDS-PAGE analysis. On the UV-vis spectra, the 303 nm band is assigned to an in situ modified form of bromelain. SEM images of gels containing SiO₂ particles show evident marks of these particles, while the rest of the gels containing Lubrizol or whey are more uniform. Regarding antibacterial tests, the SiO₂ gel samples did not show inhibition in any strains, but the other tested samples varied in the size of the inhibition diameter depending on the amicrobial strain tested; the protease activity of bromelain modulates the composition of the added whey proteins. Bromelain added as a nanoencapsulated assembly better preserves its integrity. The prepared gels showed antibacterial properties. Full article

There are many nanoencapsulation systems available today. Among all these, mesoporous silica particles (MSPs) have received great attention in the last few years. Their large surface-to-volume ratio, biocompatibility, and versatility allow the encapsulation of a wide variety of drugs inside their pores. However, their chemical instability in biological fluids is a handicap to program the precise release of the therapeutic compounds. Taking advantage of the dissolving capacity of silica, in this study, we generate hollow capsules using MSPs as transitory sacrificial templates. We show how, upon MSP coating with different polyelectrolytes or proteins, fully customized hollow shells can be produced. These capsules are biocompatible, flexible, and biodegradable, and can be decorated with nanoparticles or carbon nanotubes to endow the systems with supplementary intrinsic properties. We also fill the capsules with a fluorescent dye to demonstrate intracellular compound release. Finally, we document how fluorescent polymeric capsules are engulfed by cells, releasing their encapsulated agent during the first 96 h. In summary, here, we describe how to assemble a highly versatile encapsulation structure based on silica mesoporous cores that are completely removed from the final polymeric capsule system. These drug encapsulation systems are highly customizable and have great versatility as they can be made using silica cores of different sizes and multiple coatings. This provides capsules with unique programmable attributes that are fully customizable according to the specific needs of each disease or target tissue for the development of nanocarriers in personalized medicine. Full article

Carotenoids are natural dyes and antioxidants widely used in food processing and in therapeutic formulations. However, their practical application is restricted by their high sensitivity to external factors such as heat, light, oxygen, metal ions and processing conditions, as well as by extremely low water solubility. Various approaches have been developed to overcome these problems. In particular, it was demonstrated that application of supramolecular complexes of “host-guest” type with water-soluble nanoparticles allows minimizing the abovementioned disadvantages. From this point of view, nanoencapsulation of carotenoids is an effective strategy to improve their stability during storage and food processing. Also, nanoencapsulation enhances bioavailability of carotenoids via modulating their release kinetics from the delivery system, influencing the solubility and absorption. In the present paper, we present the state of the art of carotenoid nanoencapsulation and summarize the data obtained during last five years on preparation, analysis and reactivity of carotenoids encapsulated into various nanoparticles. The possible mechanisms of carotenoids bioavailability enhancement by multifunctional delivery systems are also discussed. Full article

A significant amount of academic and industrial research efforts are devoted to the encapsulation of active substances within micro- or nanocarriers. The ultimate goal of core–shell systems is the protection of the encapsulated substance from the environment, and its controlled and targeted release. This can be accomplished by employing “stimuli-responsive” materials as constituents of the capsule shell. Among a wide range of factors that induce the release of the core material, we focus herein on the light stimulus. In polymers, this feature can be achieved introducing a photo-sensitive segment, whose activation leads to either rupture or modification of the diffusive properties of the capsule shell, allowing the delivery of the encapsulated material. Micro- and nano-encapsulation techniques are constantly spreading towards wider application fields, and many different active molecules have been encapsulated, such as additives for food-packaging, pesticides, dyes, pharmaceutics, fragrances and flavors or cosmetics. Herein, a review on the latest and most challenging polymer-based micro- and nano-sized hollow carriers exhibiting a light-responsive release behavior is presented. A special focus is put on systems activated by wavelengths less harmful for living organisms (mainly in the ultraviolet, visible and infrared range), as well as on different preparation techniques, namely liposomes, self-assembly, layer-by-layer, and interfacial polymerization. Full article