Shining a Brighter Light

Fluorescence-based detection and imaging techniques are the cornerstone of modern biomedical optics, with applications ranging from the detection and quantification of biological species to the bioimaging of organelles up to organisms. The main drawback – poor sensitivity – can be enhanced by plasmonic nanostructures, but current plasmon-enhanced fluorescence methods cannot be easily integrated with existing biosensing and bioimaging platforms. To that end, we developed a simple and convenient method to exploit plasmon-enhanced fluorescence in various biosensing and bioimaging methods (1).

There are many ways to increase the sensitivity and signal-to-noise ratio of biodetection of low-abundance species. The key innovation in our approach lies in the extreme simplicity and universality of our fluorescence-enhancing system, which relies on placing a plasmonic patch (a flexible polymer film coated with plasmonic nanostructures) on the fluorophore-labeled surface. The nanostructures on the film act as antennae, concentrating light into a tiny volume around the molecules emitting fluorescence to yield a 100-fold enhancement. In this way, the plasmonic patch is a sort of magnifying glass.

We believe that the patch’s preclinical and clinical utility may not be far off. It not only enables the detection and visualization of target biological species at significantly lower concentrations, but it can also be applied to established biodetection procedures without modification. As an add-on method, it can be directly incorporated into existing bioassay workflows to generate immediate enhancement in the signal-to-noise ratio. It could even lead to the development of cheaper, more portable fluorescence readout devices for point-of-care testing in resource-limited areas. The first set of plasmonic patch products tailored for protein microarrays will be available within 12 months – but, in the meantime, we are working to further improve enhancement efficiency, and to apply the patch to DNA/RNA microarrays.