Novel halochromic cellulose nanowhiskers from rice straw: Visual detection of urea.

Colorimetric nanocomposite film sensor was fabricated by incorporating TCFH spectroscopic probe into cellulose nanowhiskers (CNW)/Urease enzyme matrix. CNW-TCFH can be used as disposable molecular biosensor in which CNW is the probe carrier comprising high surface area-to-volume ratio, urease is the catalyst and TCFH is the molecular probe. Tricyanofuran-hydrazone (TCFH) spectroscopic probe was prepared. UV-vis absorption spectra demonstrated solvatochromic behavior and a reversible color change of the tricyanofuran-hydrazone probe solution in acetone under acid/base conditions. CNW were reinforced with sodium alginate biopolymer to introduce biocomposite film. This CNW-TCFH film biosensor responds through visible color shift from light yellow to pink when exposed to urea in aqueous media. The morphology properties of CNW and CNW-TCFH films were examined by different tools. The photophysical properties of the prepared TCFH probe, including solvatochromism and pH sensory, were also studied.