Fluorophore Induced Plasmonic Current (FIPC) Detection with Mixed Metal Nanoparticle Films

Fluorophores and fluorescent species have been noted in literature to couple to plasmonically active metal nanoparticle films when these species are in their excited state. This coupling event leads to a directly detectable increase in fluorophore intensity known as Metal Enhanced Fluorescence (MEF), which has been noted in both literature by our group as well as others worldwide.<br/>Contemporary research recently has shown the relationship between these coupling event to go beyond just visual enhancement, with a portion of the excited state energy of the fluorescent species being donated to the plasmon, which in turn through a process known as electron hopping is able to transfer that to adjacent particles until a detectable current can be noted across the surface of the film. This process known as Fluorophore Induced Plasmonic Current (FIPC) serves as a means for detection of a fluorescent species without the need for traditionally optical detection schemes.<br/>One of the governing factors determining the possibility of this detectable current is the composition of the metal nanoparticle film. Preliminary research has shown the use of noble metals such as gold and silver as suitable candidates, with the strongest signals being noted from fluorophores that share a strong spectral overlap between the emissive properties of the fluorophore and the absorptive properties of the Film.<br/>My research stems off of this preliminary research and looks at previously unused metals for this FIPC research, such as Aluminum and Copper nanoparticle films, as well as the introduction of mixed metal films that are able to use the properties of multiple nanoparticles to have a strong spectral overlap for a variety of fluorophores. These mixed metal substrates are shown to have a larger working area than single metal films alone, and give a better understanding of the reaction mechanics between this energy transfer.<br/>These mixed metal substrates provide an avenue for the development of various biological and ecological assays that can be performed using fluorescence indicators, but are able to be performed outside of a traditional laboratory setting, providing real-time feedback for testing of biological and environmental samples.