Fabrication of biodegradable cellulose acetate nanofibers containing Rose Bengal dye by electrospinning technique and their antiviral efficacy under visible light irradiation

Biodegradable cellulose acetate (CA) nanofibers containing Rose Bengal (RB) dye were fabricated by electrospinning technique. RB dye, an anionic photosensitizer, has been used in photodynamic therapy due to its excellent biocompatibility and ability to absorb light to generate reactive oxygen species (ROS), but has a decisive disadvantage of water solubility on infection prevention. Firstly, water-insoluble RB dye was synthesized through complexation with cationic ionic liquid (IL) for antiviral agents. The synthesized water-insoluble RB dyes were embedded into biodegradable CA nanofibers by electrospinning. The electrospun nanofibers passed both antiviral test for φx174 virus under visible light irradiation and biodegradability-test using enzymes. The fabricated RB nanofibers absorbed light and generated ROS to inactivate the virus. As a result, the log reduction (-Log10(N/N0)) of φx174 titer under visible light reached a detection limit of 5.00 within 30 min. Also, the fabricated nanofibers were degraded up to 34 wt % in 9 weeks by lipase and cellulase enzymes compared with non-biodegradable nanofibers.

Highly efficient cellulose dissolution by alkaline ionic liquids

Alkaline ionic liquids (ILs) with unconventional organic anions were prepared and used for cellulose dissolution studies. High concentrations of cellulose were dissolved at room temperature in the phenolate based imidazolium IL [C₂mim][OPh], combined with organic solvent, and up to 45 wt-% cellulose dissolution (wt-% MCC of weight IL) was readily achieved at 100 ºC. No functionalization of the regenerated cellulose was observed during the dissolution process (FTIR). Characteristic cellulose II XRD diffraction pattern was observed after IL dissolution and regeneration of MCC. The crystallinity index (CI) of the pretreated MCC was reduced from 93.2 % to 31 %. Inert conditions were not required for the cellulose dissolution experiments. This study indicates that the IL H-bond basicity is not the only key parameter determining their cellulose dissolution ability. The alkaline ILs represent an energy efficient and sustainable approach for cellulose dissolution.

Hydroxyl Functionalized Pyridinium Ionic Liquids: Experimental and Theoretical Study on Physicochemical and Electrochemical Properties

Structurally modified hydroxyl functionalized pyridinium ionic liquids (ILs), liquid at room temperature, were synthesized and characterized. Alkylated N-(2-hydroxyethyl)-pyridinium ILs were prepared from alkylpyridines via corresponding bromide salts by N-alkylation (65–93%) and final anion exchange (75–96%). Pyridinium-alkylation strongly influenced the IL physicochemical and electrochemical properties. Experimental values for the ILs physicochemical properties (density, viscosity, conductivity, and thermal decomposition temperature), were in good agreement with corresponding predicted values obtained by theoretical calculations. The pyridinium ILs have electrochemical window of 3.0–5.4 V and were thermally stable up to 405°C. The IL viscosity and density were measured over a wide temperature range (25–80°C). Pyridine alkyl-substitution strongly affected the partial positive charge on the nitrogen atom of the pyridinium cations, as shown by charge distribution calculations. On-going studies on Mg complexes of the new ILs demonstrate promising properties for high current density electrodeposition of magnesium.