Regulating the hydrophobic part in amphiphilic triphenylamino-diarylethene fluorophores for ultrasensitive and portable detection of urinary albumin

Abstract

Sensitive and accurate detection of urinary albumin (u-ALB), preferably by user-friendly smartphone-based portable devices, is essential for the prevention and regular evaluation of chronic kidney disease (CKD). Here, we present a class of ionic aggregation-induced emission fluorogens (AIEgens) containing triphenylamine pyridinium skeleton and extended alkyl chains (TPA-Ps) as novel probes for u-ALB. Different from the previous studies focusing on regulating the number of ionic moieties, we for the first time investigated the effect of extending the hydrophobic tails on enhancing the sensitivity. Specifically, the TPA-P-C6 with one ionic moiety yet a n-hexyl chain exhibited the highest fluorescent increasing fold (> 3450) on responding to u-ALB, which has also been the highest degree among the reported ionic AIEgen-based u-ALB probes. Different stages of albuminuria (A1-A3) represented by varying u-ALB concentrations could be clearly revealed through fluorescence spectral signal readout. Additionally, the TPA-P-C6 exhibited a restored fluorescence at longer wavelength area in real urine samples, enabling fluorocolorimetric sensing and point-of-care testing by naked eye. With the assistance of smartphones for signal capturing and analysis, portable devices based on test papers, 96-well plate, and 3D-printing technique have been constructed for the on-site detection of u-ALB. Compared with the commercial dye based u-ALB indicator (G250) and test papers, the multi-color sensing signals of our probe can clearly reveal the different stages of albuminuria and offer useful proofs for early diagnosis of CKD.