AIE Nanozyme-Based Long Persistent Chemiluminescence and Fluorescence for POCT of Pathogenic Bacteria

Abstract

Pathogenic bacteria are widely distributed in diverse environments and significantly threaten human health. Point-of-care testing (POCT) is a valuable way for early warnings of bacteria threat. Herein, a chemiluminescence (CL)-based ratiometric sensing platform was constructed for sensitive POCT of bacteria according to a newly designed aggregation-induced emission (AIE) molecule. The new AIE molecule presents oxidase-like properties (named as AIEzyme) and can trigger long persistent CL of luminol (LUM) with strong intensity in the absence of H2O2. The CL emission can be monitored with the naked eye for over 2 h. The emission mechanism is explored and may be attributed to the persistent reactive oxygen species generation of the AIEzyme according to the cyclic energy transfer between the AIEzyme and luminol, which catalyzes CL of luminol. Based on the CL resonance energy transfer mechanism, an afterglow luminescence system is further developed, which is used to construct a ratiometric biosensor for detection of pathogenic bacteria. With a homemade holder as a detection room and a smartphone as an analyzer, the portable biosensing platform is used for quantitative POCT of bacteria in real samples with good recovery. The detection is free of H2O2 and an external excitation source, which not only simplifies the operation but reduces interference. Specifically, the long persistent luminescence and the ratiometric strategy can significantly improve accuracy, providing an instructive way for point-of-need analysis, for example, SARS-CoV-2 detection and bioimaging analysis.

Europium Ion-Based Magnetic-Trapping and Fluorescence-Sensing Method for Detection of Pathogenic Bacteria

“…The probe can be easily prepared by dissolving europium acetate in an aqueous solution. In contrast, sensing probes produced by other existing methods required varying durations, ranging from a few tens of minutes to several tens of hours. − As mentioned earlier, the LOD of our method for S. aureus was approximately 10 4 CFU mL –1 , determined through the calibration curve presented in Supporting Information Figure S10. When our LOD is compared with those obtained from other existing methods, it becomes apparent that our LOD is higher than those achieved by the existing methods.…”

“…Supporting Information Table S3 lists the comparison of our method with the existing fluorescence-based sensing methods − for detecting pathogenic bacteria. Evidently, the primary advantage of our approach lies in the short preparation time (∼2 min) of the sensing probes, specifically Eu 3+ .…”

Nano-based theranostic approaches for infection control: current status and perspectives

“…In general, AIEgens can be encapsulated and delivered by inorganic or organic particles, as well as MOFs. 185,200–203 Meanwhile, structure modifications of AIEgens, like the conjugation with hydrophilic groups or polymers, enable the formation of the polymeric AIE-active nanodots/nanocomposites via self-assembly. 204–206 Notably, some of these nanosystems demonstrating specific selectivity to fungal cells can also target the infections caused by particular microbe types.…”

Rational Integration of Nanozyme Probe and Smartphone Device for On‐Site Analysis

“…[64] To realize long-lasting chemiluminescence, recently, Y. Liu et al developed an oxidase (OXD)-like aggregation-induced emission (AIE) based nanozyme (AIEzyme), which could prolong the chemiluminescence of LUM (over 2 h) with strong intensity in the absence of H 2 O 2 . [65] Such enhancement was attributed to the persistent formation of reactive oxygen species (ROS) that could catalyze the LUM chemiluminescence. Furthermore, based on the chemiluminescence resonance energy transfer (CRET) from LUM to fluorescein (FL) molecules, an afterglow luminescence sensor was constructed for the pathogenic bacteria detection in a ratiometric analysis manner (Figure 2c).…”

“…(a) and (b) are reproduced from ref [63]. with permission from Elsevier, and (c) and (d) are reproduced from ref [65]. with permission from Elsevier.…”