Photodynamic activity of nanostructured fabrics grafted with xanthene and thiazine dyes against opportunistic fungi

Fabrication of Photoactive Electrospun Cellulose Acetate Nanofibers for Antibacterial Applications

The aim of the study was to investigate the process of electrostatic fabrication of cellulose acetate (CA) nanofibers containing methylene blue (MB) as a photosensitizer. The electrical, physicochemical, and biocidal properties of the prepared material were given. CA nanofibers were prepared by electrospinning method using a solvent mixture of acetone and distilled water (9:1 vv−1) and different concentrations of CA (i.e., 10–21%). Additionally, methylene blue was implemented into the polymer solution with a CA concentration of 17% to obtain fibers with photo-bactericidal properties. Pure electrospun CA fibers were more uniform than fibers with MB (i.e., ribbon shape). Fiber diameters did not exceed 900 nm for the tested polymer solutions and flow rate below 1.0 mL h−1. The polymer properties (i.e., concentration, resistivity) and other parameters of the process (i.e., flow rate, an applied voltage) strongly influenced the size of the fibers. Plasma treatment of nanofibers resulted in reduced biofilm formation on their surface. The results of photo-bactericidal activity (i.e., up to 180 min) confirmed the high efficiency of inactivation of Staphylococcus aureus cells using fibers containing methylene blue (i.e., with and without plasma treatment). The most effective reduction in the number of biofilm cells was equal to 99.99 ± 0.3%.

Chitosan-Based Drug Delivery Systems for Optimization of Photodynamic Therapy: a Review

Drug delivery systems (DDS) can be designed to enrich the pharmacological and therapeutic properties of several drugs. Many of the initial obstacles that impeded the clinical applications of conventional DDS have been overcome with nanotechnology-based DDS, especially those formed by chitosan (CS). CS is a linear polysaccharide obtained by the deacetylation of chitin, which has potential properties such as biocompatibility, hydrophilicity, biodegradability, non-toxicity, high bioavailability, simplicity of modification, aqueous solubility, and excellent chemical resistance. Furthermore, CS can prepare several DDS as films, gels, nanoparticles, and microparticles to improve delivery of drugs, such as photosensitizers (PS). Thus, CS-based DDS are broadly investigated for photodynamic therapy (PDT) of cancer and fungal and bacterial diseases. In PDT, a PS is activated by light of a specific wavelength, which provokes selective damage to the target tissue and its surrounding vasculature, but most PS have low water solubility and cutaneous photosensitivity impairing the clinical use of PDT. Based on this, the application of nanotechnology using chitosan-based DDS in PDT may offer great possibilities in the treatment of diseases. Therefore, this review presents numerous applications of chitosan-based DDS in order to improve the PDT for cancer and fungal and bacterial diseases.

Eco-Friendly Acaricidal Effects of Nylon 66 Nanofibers via Grafted Clove Bud Oil-Loaded Capsules on House Dust Mites

Acaricidal nylon 66 fabrics (AN66Fs) grafted with clove oil-loaded microcapsules (COMCs) were developed against Dermatophagoides farina (D. gallinae). The average diameter was about 2.9 µm with a range of 100 nm–8.5 µm. COMCs carried clove oil loading of about 65 vol %. COMCs were chemically grafted to electrospun nylon nanofibers by the chemical reactions between –OH groups of COMCs and –COOH end groups of nylon fabrics to form ester linkages. AN66Fs had an effect on D. farinae depending on COMCs loadings. The increase in COMCs loading of AN66Fs from 5 to 15 wt % increased from 22% to 93% mortality against D. farinae within 72 h. However, AN66Fs containing over 20 wt % COMCs were more effective, showing up to 100% mortality within 24 h because the large amount of monoterpene alcohol, eugenol. This research suggests the use of clove oil and its major constituent eugenol as eco-friendly bioactive agents that can serve as a replacement for synthetic acaricides in controlling the population of D. farinae.

Synthesis of Antifungal Agents from Xanthene and Thiazine Dyes and Analysis of Their Effects

Indoor fungi growth is an increasing home health problem as our homes are more tightly sealed. One thing that limits durability of the antifungal agents is the scarcity of reactive sites on many surfaces to attach these agents. In order to increase graft yield of photosensitizers to the fabrics, poly(acrylic acid-co-styrene sulfonic acid-co-vinyl benzyl rose bengal or phloxine B) were polymerized and then grafted to electrospun fabrics. In an alternative process, azure A or toluidine blue O were grafted to poly(acrylic acid), which was subsequently grafted to nanofiber-based and microfiber-based fabrics. The fabrics grafted with photosensitizers induced antifungal effects on all seven types of fungi in the order of rose bengal > phloxine B > toluidine blue O > azure A, which follows the quantum yield production of singlet oxygen for these photoactive dyes. Their inhibition rates for inactivating fungal spores decreased in the order of P. cinnamomi, T. viride, A. niger, A. fumigatus, C. globosum, P. funiculosum, and M. grisea, which is associated with lipid composition in membrane and the morphology of fungal spores. The antifungal activity was also correlated with the surface area of fabric types which grafted the photosensitizer covalently on the surface as determined by the bound color strength.