Preparation of biosensor based on triarylmethane loaded cellulose acetate xerogel for the detection of urea

Abstract

Urea released by kidney into blood and urine is a major reason for the gradual loss of kidney function. Therefore, it is of great importance to construct a real-time detection method for Urea. On the other side, a sponge-like microporous cellulose acetate (CA) xerogel has been introduced as a low-density biomaterial with various promising applications. In this study, a facile, portable, fast, and highly sensitive microporous CA biopolymer test dipstick, comprising triarylmethane (TAM) as a spectroscopic chromophore and urease (U) enzyme as a catalytic agent, is constructed for colorimetric detection of urea. Identification of urea occurs via proton transfer from the hydroxyl substituent of TAM to ammonia released in an aqueous environment from the hydrolysis of urea/urease reaction. Importantly, TAM probe was in-situ integrated within the generated sponge-like CA dipstick sensor assay (CA-U-TAM). This resulted in ratiometric changes of 131 nm red-shift in the absorption spectra, from 439 nm to 580 nm, as a function of the urea total content in the aqueous medium. Additionally, composition/morphology of the prepared CA-TAM dipstick was explored and revealed the presence of large surface area and high porous scaffolds with a pore size of ∼7.5 μm.