Breakthrough imaging of non-fluorescent reactions


Rebecca Pool

Wednesday, July 10, 2019 - 15:15
Image: Professor Peng Chen (right), Xianwen Mao, and colleagues from Cornell have pioneered a method to image non-fluorescent reactions. [Rocky Ye/Cornell University]
Researchers at Cornell, US, have unveiled a super-resolution method to image non-fluorescent reactions on nanoscale particles.
So-called COMPetition Enabled Imaging Technique with Super-Resolution - COMPEITS - relies on competition between fluorescent and non-fluorescent reactions, and shows promise  in decontaminating water.
“The method turned out to be actually very simple; quite simple to implement and quite simple to do,” highlights Professor Peng Chen from Chemistry at Cornell. “It really extends the imaging of reactions to an almost unlimited number of reactions.”
Super-resolved fluorescence microscopy has enabled huge advances in the chemical and biological sciences but can only interrogate molecules and particles that fluoresce - most chemical or biological processes do not involve fluorescent species.
Given this, Chen and colleagues have devised a new method that incorporates the competition between fluorescent and non-fluorescent reactions into a single-molecule fluorescence-detection scheme.
The COMPEITS set-up uses wide-field fluorescence microscopy in a photo-electrocatalytic microfluidic cell via two-laser epifluorescence illumination.
A catalyst particle catalyses both a non-fluorescent reaction and an auxiliary fluorogenic reaction.
The competition between the two reactions suppresses the fluorescent reaction, allowing it to be measured and mapped, which in turn provides information about the non-fluorescent reaction.
The fluorescent signals collected depend on the degree of competition between the two reactions.
The researchers used their method to image the oxidation of water micropollutant, hydroquinone, on bismuth vanadate catalyst particles.
Analyses revealed previously unknown behaviours of catalysts that helped render hydroquinone non-toxic.
“Many of these catalysed reactions are environmentally important,” says Chen. “So you could study them to learn how to remove pollutants from an aqueous environment.”
“This highly generalizable technique can be broadly applied to image various classes of non-fluorescent systems, such as unlabelled proteins, neurotransmitters and chemical warfare agents,” adds Chen. “Therefore, we expect COMPEITS to be a breakthrough technology with profound impacts on many fields including energy science, cell biology, neuroscience and nanotechnology.”
Research is published in Nature Chemistry.
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