Aggregation-induced-emission compounds and their Cucurbit[8]uril self-assemblies as fluorescence sensor array for the identification and discrimination of bacteria

Abstract

Bacterial infections are often harmful to human health. Thus, to guide the clinical diagnosis of bacteria, it is necessary to distinguish different bacterial species in mixed samples. In this study, two positively charged aggregation-induced emission compounds (AIEgens) TPE-P and BTP-P with good solubility were synthesized. Then, cucurbit[8]uril (Q[8]) interacted with TPE-P and BTP-P to form TPE-P@Q[8] and BTP-P@Q[8] self-assemblies. Through the electrostatic interaction of the TPE-P and BTP-P and their self-assemblies on the bacteria (P. vulgaris, E. coli, S. typhimurium, S. aureus, M. luteus and S. agalactiae), the fluorescence changed to varying degrees. Therefore, a four-component fluorescence sensor array was constructed with two AIEgens (TPE-P and BTP-P) and supramolecular complexes (TPE-P@Q[8] and BTP@Q[8]) as sensing units. In combination with linear discriminant analysis (LDA), the sensor array can identify and distinguish six species of bacteria, with a good linear relationship between Factor 1 of the array and the OD₆₀₀ value of the bacteria. Binary and ternary bacteria mixtures could be distinguished by the sensor array, providing high recognition accuracy in blind experiments. In addition, a fluorescence detection device was developed using a smartphone for the visual and convenient quantitative detection of S. typhimurium. Thus, the designed array can realize the rapid identification and quantification of bacteria.