A positively charged sensor array for identification of microorganisms using fluorescence response patterns†

Abstract

Microorganisms, such as bacteria and fungi, are ubiquitous and closely related to human life and health. The identification of microorganisms is especially important in the diagnosis of diseases. Herein, three positively charged tetraphenylethylene derivatives (PCTs) were successfully synthesized and used to form a sensor array (PCTs-Sa) to identify microorganisms. The three aggregation-induced luminogens (AIEgens) have different cationic groups, multi-color emission and hydrophobicity. By studying the binding energies of phospholipid bilayers and peptidoglycan bilayers, the interaction mechanisms between PCTs and different microorganisms were explored. PCTs and phospholipid bilayers exhibited different binding energies, resulting in differences in fluorescence imaging. They interacted with microorganisms to produce unique differential fluorescence responses. Through principal component analysis and a support vector machine with 100% accuracy, a variety of microorganisms were identified, including Gram-positive bacteria, Gram-negative bacteria and fungi, spherical bacteria with similar morphology, different mixtures of microorganisms and various concentrations of Staphylococcus aureus. This work provides a method with rapid response, high accuracy, high-throughput and no additional washing steps to identify microorganisms.