Halochromic cellulose textile obtained via dyeing with biocolorant isolated from Streptomyces sp. strain NP4

Abstract

Halochromic (pH-responsive) material was obtained by dyeing functionalized viscose fabric with a crude extract from Streptomyces sp. strain NP4. The functionalization of the fabric before dyeing was performed to make cellulose susceptible to coloration with NP4 extract. Two combined pre-treatment steps were used, oxidation to obtain dialdehyde cellulose and chitosan deposition after oxidation. Chitosan was deposited onto untreated fabric as well, while only oxidized viscose was also investigated for dyeing. Functionalization by both protocols made viscose susceptible to dyeing with the notion that the deposition of chitosan onto oxidized viscose produced the darkest shade on the material. Dyed fabrics showed visual pH responsiveness in the range pH 4-10, with a color change from pink to red (pH 4-pH 7) and a major color change from red to blue (pH 7-pH 10) whereby fabric was tested and could withstand 10 color-changing cycles. Cytotoxicity assay confirmed the non-toxic nature of dyed material, which indicates its possible use as wound dressing's indicators.