Abstract: Embodiments of the invention relate to determining the number concentration and size distribution of particles using dark-field microscopy. These embodiments are especially useful for the simultaneous determination of particle number concentration and size distribution of particles with dimensions below 4 microns.

Abstract: A device (and methods of using and manufacturing the device) having a substrate; and a plurality of spots comprising surface enhanced Raman scattering (SERS) active particles attached to the substrate, wherein the SERS active particles reflect an incoming Raman signal to produce a reflected Raman signal having a higher intensity than that of the incoming Raman signal are disclosed. Also a device (and methods of using and manufacturing the device) a substrate; and a plurality of spots comprising composite-organic-inorganic-nanoparticles (COINs) attached to the substrate are disclosed.

Abstract: Embodiments of the present invention provide methods for determining the degenerate binding capabilities of antibodies. The methods provide information about degenerate binding capabilities without the use of involved procedures. Optionally, a molecule toward which an antibody exhibits degenerate binding ability may be identified through the use of a reporter, such as, a composite organic inorganic nanocluster (COIN). COINs are sensitive SERS (surface enhanced Raman spectroscopy) reporters capable of multiplex analysis of analytes.

Abstract: Embodiments of the invention relate to detecting binding of a first analyte to a second analyte by Raman spectroscopy. An embodiment includes attaching one analyte to a substrate and then detecting the binding of another analyte to the analyte on the substrate by Raman spectroscopy. Another embodiment includes contacting analytes in a fluid and then detecting the binding of one analyte to another analyte by Raman spectroscopy.