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Collecting sweat sample for onsite testing is a sophisticated process as the analysis process must be completed in a real-time with a highly absorptive and sensitive device in order to gain a useful assessment of its content. Thus, we developed a chemical probe incorporated into microfibrillated cellulose to introduce a novel, simple, robust and flexible aerogel. This chromogenic sponge-like aerogel assay demonstrated a color change from yellow to orange, red and blue depending on the sweat biochemical changes. Novel pH sensitive tricyanofuran hydrazone probe was prepared, characterized and encapsulated in-situ within microfibrillated cellulose to follow up sweat pH changes. The solvatochromic performance in several solvents of different polarities and the reversible pH correlated color change of this tricyanofuran hydrazone probe in an acetonitrile solution was explored by UV-Vis absorption spectra. The microporous and microfibrillated sponge-like cellulose substrate was fabricated by activation of wood pulp using phosphoric acid followed by freeze-drying process. Morphological characterization, thermal stability and fiber crystallinity of the prepared aerogel were explored using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The visual color change was explored by studying the CIE LAB color space coordinates and color strength values. The cytotoxicity of the sponge-like aerogel sensor was also evaluated., (Copyright © 2019 Elsevier B.V. All rights reserved.)

A simple, portable and highly sensitive naked-eye test strip is successfully prepared for optical detection of gaseous and aqueous alkaline analytes. Novel pH-sensory tricyanofuran-hydrazone (TCFH) disperse colorant containing a hydrazone recognition functional moiety is successfully synthesized via azo-coupling reaction between active methyl-containing tricyanofuran (TCF) heterocycle and diazonium salt of 4-aminobenzaldehyde followed by Knoevenagel condensation with malononitrile. UV-vis absorption spectra display solvatochromism and reversible color changes of the TCFH solution in dimethyl sulfoxide in response to pH variations. We investigate the preparation of hydrophobic cellulose/polyethylene terephthalate composites characterized by their high affinity for disperse dyes. Composite films made from CA, Cell/CA, PET/CA, and Cell/PET-CA are produced via solvent-casting procedure using 10-30% modified cellulose or modified polyethylene terephthalate. The mechanical properties and morphologies of these composite films are investigated. The prepared pH-sensory hydrazone-based disperse dye is then applied to dye the produced cellulose-based composite films employing the high temperature pressure dyeing procedure. The produced halochromic PET-CA-TCFH test strip provide an instant visible signal from orange to purple upon exposure to alkaline conditions as proved by the coloration measurements. The sensor strip exhibits high sensitivity and quick detection toward ammonia in both of aqueous and vapor phases by naked-eye observations at room temperature and atmospheric pressure., (Copyright © 2017 Elsevier B.V. All rights reserved.)