Performances and Biocompatibility of Prepared pH-Sensitive Cotton/Polyamide 6 Medical Dressings Dyed with Halochromic Dyes

A natural pH-sensitive dye, curcumin, and a synthetic pH-sensitive dye, Bromothymol blue, were successfullyapplied on cotton/polyamide 6 medical dressings. The work addresses two different topics: on the one hand the dyeingprocess of the medical devices; on the other hand, the evaluation of the dyed medical dressing biocompatibility. Differentdye concentrations were tested to find the best dye exhaustion and dye fastness to washing and perspiration. The halochromictest evidenced a pH sensitivity in a range of pH from 5.5 to 8.0 and 8.5. These properties confirmed their possible usage aspotential pH textile sensors in the control of skin diseases. The last sections examine the biocompatibility of the preparedmedical devices with human skin. MTT assay on in vitro cultures of human epithelial cells (HaCaT keratinocytes) wasperformed to test the cytotoxicity. In vitro permeation studies with Franz cells were performed as well to evaluate the dyepotential accumulation in the skin layers. No cytotoxicity was detected as well as no dye permeation through the skin layers.