Chitosan-based films filled with nanoencapsulated essential oil: Physical-chemical characterization and enhanced wound healing activity

The economic burden of chronic wounds, the complexity of the process of tissue repair and the possibility of resistant bacterial infections, have triggered a significant research interest in the application of natural alternative therapies for wound healing. Biomolecules are intrinsically multi-active, as they affect multiple mechanisms involved in tissue repair phenomenon, including immunomodulatory, anti-inflammatory, cell proliferation, extra cellular matrix remodeling and angiogenesis. Chitosan features a unique combination of attributes, including intrinsic hemostatic, antimicrobial, and immunomodulatory properties, that make it an exceptional candidate for wound management, in the development of wound dressings and scaffolds. In this study, we produced nanoemulsions (NE) loaded with SFO, characterized them, and evaluated their tissue repairing properties. Dynamic light scattering (DLS) analysis confirmed the formation of a nanoemulsion with a droplet size of 21.12 ± 2.31 nm and a polydispersity index (PdI) of 0.159, indicating good stability for up to 90 days. To investigate the potential wound healing effects, SFO-loaded NE were applied on male C57BL/6 mice for seven consecutive days, producing a significantly higher wound closure efficiency (p < 0.05) for the group treated with SFO-loaded NE compared to the control group treated with the saline solution. This finding indicates that the SFO-loaded NE exhibits therapeutic properties that effectively promote wound healing in this experimental model. Then, SFO-loaded NE were incorporated into chitosan:polyvinyl alcohol (PVA)-based films. The inclusion of NE into the polymer matrix resulted in increased lipophilicity reflected by the contact angle results, while decreasing moisture absorption, water solubility, and crystallinity. Moreover, FTIR analysis confirmed the formation of new bonds between SFO-NE and the film matrix, which also impacted on porosity properties. Thermal analysis indicated a decrease in the glass transition temperature of the films due to the presence of SFO-NE, suggesting a plasticizing role of NE, confirmed by XRD results, that showed a decrease in the crystallinity of the blend films upon the addition of SFO-NE. AFM images showed no evidence of NE droplet aggregation in the Chitosan:PVA film matrix. Moisture absorption and water content decreased upon incorporation of SFO-loaded NE. Although the inclusion of NE increased hydrophobicity and water contact angle, the values remained within an acceptable range for wound healing applications. Overall, our results emphasize the significant tissue repairing properties of SFO-loaded NE and the potential of Chitosan:PVA films containing nanoencapsulated SFO as effective formulations for wound healing with notable tissue repairing properties.

Development, characterization and evidence of anti-endometriotic activity of Phytocannabinoid-Rich nanoemulsions

During the last decades, the cannabinoid research for therapeutic purposes has been rapidly advancing, with an ever-growing body of evidence of beneficial effects for a wide sort of conditions, including those related to mucosal and epithelial homeostasis, inflammatory processes, immune responses, nociception, and modulating cell differentiation. β-caryophyllene (BCP) is a lipophilic volatile sesquiterpene, known as non-cannabis-derived phytocannabinoid, with documented anti-inflammatory, anti-proliferative and analgesic effects in both in vitro and in vivo models. Copaiba oil (COPA) is an oil-resin, mainly composed of BCP and other lipophilic and volatile components. COPA is reported to show several therapeutic effects, including anti-endometriotic properties and its use is widespread throughout the Amazonian folk medicine. COPA was nanoencapsulated into nanoemulsions (NE), then evaluated regarding the potential for transvaginal drug delivery and providing endometrial stromal cell proliferation in vitro. Transmission electron microscopy (TEM) showed that spherical NE were obtained with COPA concentration that varied from 5 to 7 wt%, while surfactant was maintained at 7.75 wt%. Dynamic light scattering (DLS) measurements showed droplet sizes of 30.03 ± 1.18, 35.47 ± 2.02, 43.98 ± 4.23 and PdI of 0.189, 0.175 and 0.182, respectively, with stability against coalescence and Ostwald ripening during 90 days. Physicochemical characterization results suggest that NE were able to both improve solubility and loading capacity, and increase thermal stability of COPA volatile components. Moreover, they showed slow and sustained release for up to eight hours, following the Higuchi kinetic model. Endometrial stromal cells from non-endometriotic lesions and ectopic endometrium were treated with different concentrations of COPA-loaded NE for 48 h to evaluate its effect on cell viability and morphology. The results suggested significant decrease in cell viability and morphological modifications in concentrations higher than 150 μg/ml of COPA-loaded NE, but not when cells were treated with the vehicle (without COPA). Given the relevance of Copaifera spp. species in folk medicine and their bio economical importance in the Amazon, the development of novel formulations to overcome the technological limitations related to BCP and COPA, is promising. Our results showed that COPA-loaded NE can lead to a novel, uterus-targeting, more effective and promising natural alternative treatment of endometriosis.

Nanosystems for gene therapy targeting brain damage caused by viral infections

Several human pathogens can cause long-lasting neurological damage. Despite the increasing clinical knowledge about these conditions, most still lack efficient therapeutic interventions. Gene therapy (GT) approaches comprise strategies to modify or adjust the expression or function of a gene, thus providing therapy for human diseases. Since recombinant nucleic acids used in GT have physicochemical limitations and can fail to reach the desired tissue, viral and non-viral vectors are applied to mediate gene delivery. Although viral vectors are associated to high levels of transfection, non-viral vectors are safer and have been further explored. Different types of nanosystems consisting of lipids, polymeric and inorganic materials are applied as non-viral vectors. In this review, we discuss potential targets for GT intervention in order to prevent neurological damage associated to infectious diseases as well as the role of nanosized non-viral vectors as agents to help the selective delivery of these gene-modifying molecules. Application of non-viral vectors for delivery of GT effectors comprise a promising alternative to treat brain inflammation induced by viral infections.

Polymer-based Drug Delivery Systems Applied to Insects Repellents Devices: A Review

Insects-borne diseases constitute a public health concern. Since there is no vaccine or curative treatment for many of these diseases, individual protection is the main approach to prevent them. Nowadays, the search for replacing synthetic molecules for insect repellents from natural sources, such as essential oils, is increasing. However, most of them present low efficiency compared to synthetic repellents. Therefore, decreasing skin permeation of synthetic repellents or yet, increasing effectiveness of natural repellents are challenges that must be overcome during the development of novel insect repellent formulations. In this context, polymer-based formulations allow entrapping active ingredients and provide release control. Encapsulation into polymeric micro/nanocapsules, cyclodextrins, polymeric micelles or hydrogels constitutes an approach to modify physicochemical properties of encapsulated molecules. Such techniques, applied in topical formulations, fabrics modification for personal protection, or food packaging have proved to be more effective in increasing repellency time and also in reducing drug dermal absorption, improving safety profiles of these products. In this work, the main synthetic and natural insect repellents are described as well as their polymeric carrier systems and their potential applications.