Synthesis, Application, and Antibacterial Activity of New Direct Dyes based on Chromene Derivatives.

AIMS: This study aimed at synthesizing, analyzing, and utilizing two new direct dyes based on chromene derivatives as the chromophoric moiety in dyeing wool, silk, and cotton, with good color strength, light fastness, and other desirable features. BACKGROUND: New direct dyes with antimicrobial activities for Gram-positive, Gram-negative bacteria, and fungus are being developed. These dyes are used on cotton, silk, and wool materials, which have excellent light fastness, washing, rubbing, and perspiration fastness. METHODS: All dyeing fabrics were tested for antibacterial activity. As a part of the experiment, parent structure 1 was previously synthesized. Then, diazotization and coupling reactions were used to prepare these dyes. RESULTS AND DISCUSSION: P-Aminobenzenesulfonic acid (C1) and 4-Aminoazobenzene-3,4'-disulfonic acid (C2) were diazotized in hydrochloric acid with sodium nitrite and then coupled with compound 1 in a molar ratio of 1:1 at 25 °C until the pH was fixed at 5. Finally, the monoazo and diazo direct dyes (D1 and D2) were prepared. CONCLUSION: Wool, silk, and cotton materials benefit from the increased antibacterial activities and dyeing qualities (exhaustion and fixing) of synthetic dyes. Furthermore, they offer excellent fastness qualities (light, rubbing, and perspiration).

Preparation and characterization of green carboxymethylchitosan (CMCS) - Polyvinyl alcohol (PVA) electrospun nanofibers containing gold nanoparticles (AuNPs) and its potential use as biomaterials.

Green chemistry was used in nanostructures preparation to impart it amazing innovating application in the medical field. Herein we prepared novel, cost effective and ultra-safe antibacterial nanocomposite. This nanocomposite contains carboxymethylchitosan (CMCS) as safe reducing agent for gold nanoparticles (AuNPs) and polyvinyl alcohol (PVA) as nanofiber aiding material formation. The AuNPs has spherical shapes, its diameter ranged from 15 to 25 nm and uniform distributed within CMCS nanofibers. The optimum conditions for electrospinning were 10 wt% total solution contains 2 wt% CMCS and 8 wt% PVA. UV-vis, TEM and XRD were used to characterize AuNPs whereas FTIR and SEM were used to characterize nanofibers. Results showed that ultra-fine fibers were generated after addition of PVA to CMCS solution. Also, CMCS nanofibers containing AuNPs has excellent antibacterial activity towards tested bacteria. Finally, the cytotoxicity of CMCS has been evaluated through Cell viability assay, which confirm that the nanofiber composite is non-toxic and tissue compatible.