Scheme for target mRNA detection using nano-flares. The binding of the target mRNA to the nano-flare releases a fluorescent probe. Taken from Proc. Natl. Aca. Sci. USA 2014, 111, 17104.
Nano-flares are comprised of spherical nucleic acid (SNA)-gold nanoparticle conjugates hybridized to short, fluorophore-labeled “reporter” sequences. In a typical assay, when nano-flares encounter target mRNA in the cellular environment, the mRNA binds to the DNA on the particle surface, displacing and releasing the reporter strands. Upon release, an increase in fluorescence signal is observed because the fluorescence of the labeled reporter is no longer quenched in close proximity to the gold nanoparticle surface. Nano-flares provided the first way to sort live cells based upon their internal genetic contents, as opposed to their external protein markers, the previous paradigm. Since its original inception, versions of the nano-flare platform have been developed to detect small molecules like ATP, track and isolate live circulating tumor cells (CTCs) and stem cells, identify abnormal scars, and screen drug libraries for candidate molecules that specifically up- or down-regulate genes within a living cell. Nano-flares were commercialized and sold as SmartFlares™. Over 1,600 versions have been available in over 120 countries from Millipore and AuraSense and now from Canopy Biosciences.
Left: Nano-flares have been commercialized and sold as SmartFlares by AuraSense/Merck Millipore (http://www.emdmillipore.com/US/en/life-science-research/genomic-analysis/SmartFlare-Live-Cell-RNA-Detection/ZdGb.qB.KCcAAAFLAQs0i.s1,nav) and now Canopy Biosciences.