Polymer‐Templated Perylene‐Probe Noncovalent Self‐Assembly: A New Strategy for Label‐Free Ultrasensitive Fluorescence Turn‐On Biosensing

Abstract

A new label-free fluorescence turn-on strategy for highly sensitive biosensing has been developed. A negatively charged perylene probe was synthesized. Polycations could induce aggregation of the perylene probe through noncovalent interactions and the fluorescence of the probe's monomer was efficiently quenched. Upon addition of a single-stranded nucleic acid, competitive binding of the negatively charged nucleic acid (a polyanion) to the cationic polymer resulted in the release of a monomer and thus a turn-on fluorescence signal was detected. Without the use of any amplification techniques, a detection limit of 2 pM DNA was obtained. Based on these results, an assay strategy for the highly sensitive detection of alkaline phosphatase (ALP) activity has been demonstrated. λ Exonuclease (λ exo) could degrade 5'-phosphorylated single-stranded DNA. However, when the DNA sample was treated with ALP, the phosphate functional group was removed by ALP and it could no longer be degraded by λ exo. Binding of the DNA to the perylene probe-polycation complex resulted in a turn-on fluorescence signal, which could be used for sensing of ALP. The method is highly sensitive, a limit of detection as low as 0.02 mU mL(-1) ALP was obtained. Our method is simple, convenient, highly sensitive, and inexpensive.

A ratiometric fluorescence assay for acetylcholinesterase activity and inhibitor screening based on supramolecular assembly induced monomer–excimer emission transition of a perylene probe

“…40 In the buffer solution, PDI-DHA displays unique monomer emission with peaks at 548 and 587 nm. The amphiphilic compound lauroylcholine was employed to be a good substrate for AChE and introduce the PDI-DHA aggregation.…”

“…40 Lauroylcholine was bought from Aladdin (Shanghai, China). Lauric acid was purchased from Dayang Chemicals Co., Ltd. Trypsin and acetylcholinesterase was ordered from Sigma.…”

Improving thermal and mechanical properties of epoxy composites by using functionalized graphene

“…The 1 H NMR results were compared with the literature data, thereby it further confirmed the correct structure. 23,34 The characterization data of PBI were as follows: 1 Fig.2(b), shows that the proton resonances belonging to -OH of the PBI-HPG could be found at 2.09 ppm and the proton resonances of -CH 2 -and -CH-of hyperbranched polyglycidyl were observed at 3.49-4.23 ppm. 24 Fig.3(a) shows the zeta potential of the PBI-HPG/RGO measured at different pH in distilled water.…”

“…Then the dark-red precipitate was washed with deionized water until the filtrate was at a nearly neutral pH value. 23 The product was dried at 60 o C in a vacuum drying oven to gain a red brown powder.…”

Colorimetric detection of Hg2+ using a mixture of an anionic azo dye and a cationic polyelectrolyte in aqueous solution

“…Poly(diallyldimethylammonium chloride) (PDADMAC) is a water‐soluble cationic polyelectrolyte with quaternary ammonium groups . Anionic dyes can interact with PDADMAC by electrostatic interactions to have the potential to form their self‐aggregate and show distinct spectroscopic and sensing properties from those of monomeric dyes . Our previous study reported that a chemosensor through the electrostatic combination of an anionic organic dye, pyrogallol red (PR), and PDADMAC exhibited a colorimetric selective detection for Zn 2+ distinct from PR .…”