Ultrabright fluorescent nanocomposite structures for enhanced fluorescent bioassays

A fluorescent nanocomposite structure comprising:

• a plasmonic nanostructure having at least one localized surface plasmon resonance wavelength (λLSPR);
• at least one spacer coating;
• at least one fluorescent agent having a first maximum excitation wavelength (λEX1) and a first maximum emission wavelength (λEM1);
• and
• at least one fluorescent agent having a second maximum excitation wavelength (λEX2) and a second maximum emission wavelength (λEM2),
• wherein the fluorescent nanocomposite structure can be excited with light at λEX1 and can emit light at λEM2, and
• wherein an intensity of emission at λEM2 is greater than an intensity of emission at λEM1.

A method of identifying T-cells with specific T-cell receptors, the method comprising:

• providing a sample containing T-cells;
• contacting the sample containing T-cells with a fluorescent nanocomposite structure comprising at least one major histocompatibility complex (MHC) molecule loaded with a peptide (pMHC) that can specifically bind to T-cells containing receptors specific to the peptide;
• spatially separating the T-cells;
• exciting the fluorescent nanocomposite structure with a wavelength of light that will induce fluorescence emission;
• and
• detecting the T-cells that are labeled with the fluorescent nanocomposite structure.