Aggregation-Switching Strategy for Promoting Fluorescent Sensing of Biologically Relevant Species: A Simple Near-Infrared Cyanine Dye Highly Sensitive and Selective for ATP

Abstract

We report a strategy for enhanced performance of fluorescent sensing of biologically relevant species that often bind with natural receptors via multiple interactions. We propose making a fluorescent sensory molecule to form H-aggregates such that its emission is quenched leaving a low background, and upon binding to a biologically relevant species, the aggregate switches to another form in which the fluorescent species is better protected to afford a stronger emission signal. Meanwhile, the aggregated fluorescent dyes afford multiple interactions with the sensing species that require multiple binding sites. The lower background, stronger binding, and stronger signal would therefore lead to a much higher sensing performance, as improved selectivity would also result in along with the signal amplification. We thus designed a near-IR cyanine dye bearing two boronic acid groups (Cy-BA) for fluorescent sensing of ATP such that the boronic acid groups in the dye molecule bind to the cis-diol moiety in ATP. Introduction of the cationic surfactant dodecyltrimethylammonium bromide (DTAB) below its critical aggregation concentration is key because Cy-BA molecules made into H-aggregates were practically nonfluorescent. Upon mixing with ATP, a dramatic enhancement in the fluorescence occurred because of the formation of ATP/Cy-BA/DTAB vesicles in which the fluorescent dye is well dispersed and protected. This sensing scheme, despite the dynamic nature of the boronic acid/cis-diol interaction, weakness of the electrostatic interactions among ATP/Cy-BA/DTAB, and poor selectivity of these interactions, allows for highly sensitive and selective detection of ATP in aqueous solution.

Nanostructured Luminescent Micelles: Efficient “Functional Materials” for Sensing Nitroaromatic and Nitramine Explosives

“…Considering the advancement of nanotechnology and nanoscience, nanostructured micellar probes have been considered as a promising candidate for bio-sensing owing to their structural flexibility and versatility [62]. However, only a handful of luminescent biosensor probes based on micellar systems appeared in the recent literature [16][17][18][19][20][63][64][65][66][67][68][69][70][71][72][73][74]. We will provide a very brief glimpse on these luminescent biosensors, which are used to create self-assembled nanostructure materials showing promise for use as next generation potential as "functional materials".…”

“…Likewise, Jiang et al recently reported a luminescent micellar system [20] for ATP, comprised of a cationic surfactant, dodecyltrimethylammonium bromide (DTAB), and a near infrared (NIR) emissive cyanine dye. As mentioned above, a similar π−π staking within ATP and dye molecule triggered an effective energy transfer (ET) from the dye to ATP that resulted in significant quenching of emission intensity.…”

“…These luminophoric materials are used to demonstrate the rudimentary models for various CT/ET processes in an aqueous solution in the presence of various chemical entities [1][2][3][4][5][6][7]. Based on the fundamental idea of CT/ET transition, a considerable number of elegant luminous micellar systems are developed for sensing metal ions [8][9][10][11][12] and anions [13][14][15], biomolecules [16][17][18][19][20], detection of explosive [21][22][23][24][25], etc. to name a few.…”

Development of Dipicolylamine-Modified Cyclodextrins for the Design of Selective Guest-Responsive Receptors for ATP

“…The affinity of these CyD hosts for nucleotides or nucleosides has been well investigated, although there are still few applications of CyDs to chemical sensors [ 19 , 20 , 21 , 22 , 23 , 24 ]. On the other hand, ATP recognition has been studied because of its significant roles in biological systems, and thus a number of ATP-targeting fluorescent probes have been reported over the last few decades [ 25 , 26 , 27 ]. However, there have been few examples of turn-on type chemical indicators that can distinguish nucleoside triphosphate from similar derivatives.…”

Target Recycling Transcription of Lighting-Up RNA Aptamers for Highly Sensitive and Label-Free Detection of ATP

“…Under normal circumstances, the ATP concentration in the human body is strictly self-regulated. However, intensive research evidences have also confirmed that abnormal ATP concentration is closely indicative to several diseases, for instance, hypoglycemia, cardiovascular disease, Alzheimer's disease, as well as various cancers [5][6][7]. In nerve system, ATP connects non-neural cells and nerve cells to perform the important function of sensory transmission, therefore monitoring trace amounts of ATP is conducive to understand its integration in the brain [8].…”