Accurate and sensitive probing of onset of micellization based on absolute aggregation‐caused quenching effect

Abstract

Probing the onset of micellization, or determining the critical micelle concentration (CMC), is of crucial importance while remains to be challenged by growing demand for extraordinary sensitivity and accuracy. Although fluorometry has attracted wide attention owing to its superiority in simplicity and sensitivity over other methods, the presence and fluctuation of background fluorescence of conventional fluorescent probes undermine the accuracy of CMC determination. Herein, a series of novel fluorescent probes without background fluorescence at a concentration below CMC owing to absolute aggregation‐caused quenching (aACQ) are utilized for sensitive and accurate measurement of CMC. The aACQ probes aggregate spontaneously and instantly in an aqueous environment owing to molecular π–π stacking with fluorescence quenching absolutely. Therefore, the absence of background fluorescence at a concentration below CMC clears relevant interference associated with conventional fluorophores. In this study, the new method is applied for versatile surfactants with CMCs ranging from nanomolar to millimolar concentrations, especially copolymers with ultralow CMC. The higher sensitivity and accuracy are highlighted by comparison with conventional probes.

Determination of the critical micelle concentration of surfactants using fluorescence strategies

“…NIR fluorophores based on aza-dipyrromethene boron difluoride (aza-BODIPY) are prone to the ACQ effect in water, where the quenched fluorescence can be quickly restored by molecularly dispersing into micelles. 66 Using the turn-on fluorescence, the CMC values of various surfactants can be determined sensitively (Fig. 5a).…”

Fluoride-regulated colorimetric and fluorometric switch through B–F dynamic covalent reactions of AIEgens

“…4a). 36 To verify this hypothesis, as shown in Fig. 4b and c, the differences between 1 H NMR and 19 F NMR spectra of DTDB before and after adding 8 eq.…”

Selection of an aggregation-caused quenching-based fluorescent tracer for imaging studies in nano drug delivery systems

“…Though ACQ was regarded to be unfavorable for fluorophores due to reduced luminance, it has recently been found to be valuable for tracking nanocarriers for drug delivery. 25,26 While FRET-and AIE-based fluorophores are well suited for in vitro studies, ACQ dyes demonstrate supremacy in exploration of the in vivo behaviors of drug nanocarriers over conventional fluorescent dyes, such as DiR (Scheme 1), as demonstrated in our previous publications. 19,[27][28][29][30] DiR has been used for NDDS, but it usually gives confusing and misleading signals when dissociated from nanocarriers.…”