Multimode Chiroptical Spectrometer for Nanoparticle Characterization

This project will develop a new scientific instrument optimized for the advanced characterization of near-infrared fluorescent nanoparticles that can exist as left- or right-handed structures (enantiomers). Single-walled carbon nanotubes (SWCNTs) are currently the leading example of such nanomaterials. Applied NanoFluorescence, LLC (ANF) proposes a novel multi-mode chiroptical spectrometer that can distinguish left and right enantiomers through their differing interactions with circularly polarized light. The proposed instrument will offer four complementary measurement modes. These modes are (1) fluorescence-detected circular dichroism (FDCD) spectra with visible excitation (400-700 nm) and near-infrared emission (900-1600 nm); (2) rapid excitationemission fluorimetry covering the same visible excitation and near-infrared emission ranges; (3) direct nearinfrared circular dichroism absorption spectra; and (4) normal near-infrared absorption spectra. Unlike existing FDCD instruments, mode (1) will offer spectral selection of the emission wavelength, thus allowing structurespecific measurements of CD spectra in unsorted SWCNT samples. Mode (2) will measure full excitation-emission maps with peak signal-to-noise ratios above 100 in less than 2 minutes. All four measurement modes will be performed under computer control. The combined results will offer powerful analyses of complex nanoparticle samples and their coatings, guiding production, processing, and application development.