Drug Delivery Systems for Photodynamic Therapy: The Potentiality and Versatility of Electrospun Nanofibers.

Recently, photodynamic therapy (PDT) has become a promising approach for the treatment of a broad range of diseases, including oncological and infectious diseases. This minimally invasive and localized therapy is based on the production of reactive oxygen species able to destroy cancer cells and inactivate pathogens by combining the use of photosensitizers (PSs), light, and molecular oxygen. To overcome the drawbacks of drug systemic administration, drug delivery systems (DDS) can be used to carrier the PSs, allowing higher therapeutic efficacy and minimal toxicological effects. Polymeric nanofibers produced by electrospinning emerged as powerful platforms for drug delivery applications. Electrospun nanofibers exhibit outstanding characteristics, such as large surface-area-to-volume ratio associated with high drug loading, high porosity, flexibility, ability to incorporate and release a wide variety of therapeutic agents, biocompatibility, and biodegradability. Due to the versatility of this technique, fibers with different morphologies and functionalities, including drug release profile can be produced. The possibility of scalability makes electrospinning even more attractive for the development of DDS. This review aims to explore and show an up to date of the huge potential of electrospun nanofibers as DDS for different PDT applications and discuss the opportunities and challenges in this field.

Active natural-based films for food packaging applications: The combined effect of chitosan and nanocellulose.

This work aimed to evaluate the potential of chitosan/cellulose nanocrystals (CNC) films to be used as active pads for meat packages to prolong its shelf-life and preserve its properties over time. Several CNC concentrations (5, 10, 25, and 50 wt%) were tested and the films were produced by solvent casting. The developed samples were characterized by ATR-FTIR, TGA, FESEM, and XRD. The transparency, antimicrobial, barrier and mechanical properties were also assessed. Finally, the films' ability to prolong food shelf-life was studied in real conditions using chicken meat. CNC incorporation improved the thermal stability and the oxygen barrier while the water vapor permeability was maintained. An enhancement of mechanical properties was also observed by the increase in tensile strength and Young's modulus in chitosan/CNC films. These films demonstrated bactericidal effect against Gram-positive and Gram-negative bacteria and fungicidal activity against Candida albicans. Lastly, chitosan-based films decreased the growth of Pseudomonas and Enterobacteriaceae bacteria in meat during the first days of storage compared to commercial membranes, while chitosan/CNC films reduced the total volatile basic nitrogen (TVB-N), indicating their efficiency in retarding meat's spoilage under refrigeration conditions. This work highlights the great potential of natural-based films to act as green alternatives for food preservation.

Early myocardial changes induced by doxorubicin in the nonfailing dilated ventricle.

Several studies have demonstrated that administration of doxorubicin (DOXO) results in cardiotoxicity, which eventually progresses to dilated cardiomyopathy. The present work aimed to evaluate the early myocardial changes of DOXO-induced cardiotoxicity. Male New Zealand White rabbits were injected intravenously with DOXO twice weekly for 8 wk [DOXO-induced heart failure (DOXO-HF)] or with an equivolumetric dose of saline (control). Echocardiographic evaluation was performed, and myocardial samples were collected to evaluate myocardial cellular and molecular modifications. The DOXO-HF group presented cardiac hypertrophy and higher left ventricular cavity diameters, showing a dilated phenotype but preserved ejection fraction. Concerning cardiomyocyte function, the DOXO-HF group presented a trend toward increased active tension without significant differences in passive tension. The myocardial GSSG-to-GSH ratio and interstitial fibrosis were increased and Bax-to- Bcl-2 ratio presented a trend toward an increase, suggesting the activation of apoptosis signaling pathways. The macromolecule titin shifted toward the more compliant isoform (N2BA), whereas the stiffer one (N2B) was shown to be hypophosphorylated. Differential protein analysis from the aggregate-enriched fraction through gel liquid chromatography-tandem mass spectrometry revealed an increase in the histidine-rich glycoprotein fragment in DOXO-HF animals. This work describes novel and early myocardial effects of DOXO-induced cardiotoxicity. Thus, tracking these changes appears to be of extreme relevance for the early detection of cardiac damage (as soon as ventricular dilation becomes evident) before irreversible cardiac function deterioration occurs (reduced ejection fraction). Moreover, it allows for the adjustment of the therapeutic approach and thus the prevention of cardiomyopathy progression. NEW & NOTEWORTHY Identification of early myocardial effects of doxorubicin in the heart is essential to hinder the development of cardiac complications and adjust the therapeutic approach. This study describes doxorubicin-induced cellular and molecular modifications before the onset of dilated cardiomyopathy. Myocardial samples from doxorubicin-treated rabbits showed a tendency for higher cardiomyocyte active tension, titin isoform shift from N2B to N2BA, hypophosphorylation of N2B, increased apoptotic genes, left ventricular interstitial fibrosis, and increased aggregation of histidine-rich glycoprotein.

Multifunctional Flax Fibres Based on the Combined Effect of Silver and Zinc Oxide (Ag/ZnO) Nanostructures.

Cellulosic fibre-based smart materials exhibiting multiple capabilities are getting tremendous attention due to their wide application areas. In this work, multifunctional flax fabrics with piezoresistive response were developed through the combined functionalization with silver (Ag) and zinc oxide (ZnO) nanoparticles (NPs). Biodegradable polyethylene glycol (PEG) was used to produce AgNPs, whereas ZnONPs were synthetized via a simple and low-cost method. Flax fabrics with and without NPs were characterized by Ground State Diffuse Reflectance (GSDR), Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive Spectroscopy (EDS), X-ray Diffraction (XRD), Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR), and Thermogravimetric analysis (TGA). After creating a conductive surface by flax functionalization with AgNPs, ZnONPs were synthetized onto these fabrics. The developed fibrous systems exhibited piezoresistive response and the sensor sensitivity increased with the use of higher ZnO precursor concentrations (0.4 M). Functionalized fabrics exhibited excellent antibacterial activity against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria, higher hydrophobicity (WCA changed from 0° to >100°), UV radiation resistance, and wash durability. Overall, this work provides new insights regarding the bifunctionalization of flax fabrics with Ag/ZnO nanostructures and brings new findings about the combined effect of both NPs for the development of piezoresistive textile sensors with multifunctional properties.