PDA–PEI-Copolymerized Nanodots with Tailorable Fluorescence Emission and Quenching Properties for the Sensitive Ratiometric Fluorescence Sensing of miRNA in Serum

Abstract

Dopamine and polyethyleneimine (PEI) copolymerized nanodots (PDA–PEI nanodots) with both fluorescence emission and quenching features were synthesized by a simple one-step reaction at room temperature. By adjusting the dopamine and PEI ratio as well as the chain length of PEI, the fluorescence emission and quenching properties of PDA–PEI nanodots can be controlled well. Under optimal conditions, the nanodots showed strong green fluorescence emission with an absolute quantum yield of 1–2% and a quenching efficiency of more than 99% to several fluorophores with emission wavelengths ranging from blue to red light regions. The nanodots with a large number of functional groups also showed strong affinity to nucleic acid strands, excellent solubility in aqueous solution, long-term stability, and uniform size distribution. Integrating these attractive features with the specific enzymatic digestion reaction of the DSN enzyme, a highly sensitive ratiometric fluorescence nanoprobe for miRNA analysis was developed. Aminomethylcoumarin acetate (AMCA), which possesses the same excitation wavelength but a well-resolved blue fluorescence emission with PDA–PEI nanodots, was selected as the signal-reporting unit for capture probe labeling, while the inherent green fluorescence of PDA–PEI nanodots served as the reference. According to the ratiometric fluorescence signal, the ratiometric fluorescence nanoprobes showed high sensitivity and good accuracy for the miRNA assay. Because of the high and universal quenching efficiency, stable fluorescence emission, easily assembled interface, and uniform morphology, the nanodots may have great application prospects to serve as a universal nanoplatform for the fabrication of ratiometric fluorescence nanoprobes.

Polydopamine-Based Nanoprobes Application in Optical Biosensing

“…miRNA detection was also successfully performed in fetal bovine serum as a first demonstration of the performances of PDA-PPy NS in real samples. Thanks to its fluorescence and quenching properties, PDA can also be used as a ratiometric probe, as described in the work of Deng et al [82]. They synthesized nanodots (average diameter of 6.7 nm) from the copolymerization of PDA and polyethyleneimine (PEI).…”

A label-free fluorescent sensor for rapid and sensitive detection of ctDNA based on fluorescent PDA nanoparticles

“…After this phenomenon was reported, FL-PDA NPs have been used in bioimaging, 11 antibacterial treatment, 12,13 tumor therapy 14 and biosensor detection. [15][16][17] For example, Kong et al 18 reported a cost-effective glutathione (GSH) sensor using FL-PDA NPs as a fluorescent signal indicator. Dopamine (DA) was rapidly oxidized into quinone derivatives in the presence of MnO 2 nanosheets (MnO 2 NSs) and then self-polymerized into FL-PDA NPs with the maximum emission intensity at 485 nm, while GSH has the ability to reduce MnO 2 NSs to Mn 2+ , thus inhibiting the formation of FL-PDA NPs.…”