A novel encoding system and methods for determining the location and/or
identity of a particular item or component of interest is provided. In
particular, the present invention utilizes a "barcode" comprising one or
more sizes of semiconductor nanocrystals (quantum dots) having
characteristic spectral emissions, to either "track" the location of a
particular item of interest or to identify a particular item of interest.
The semiconductor nanocrystals used in the inventive "barcoding" scheme
can be tuned to a desired wavelength to produce a characteristic spectral
emission in narrow spectral widths, and with a symmetric, nearly Gaussian
line shape, by changing the composition and size of the quantum dot.
Additionally, the intensity of the emission at a particular characteristic
wavelength can also be varied, thus enabling the use of binary or higher
order encoding schemes. The information encoded by the quantum dot can be
spectroscopically decoded, thus providing the location and/or identity of
the particular item or component of interest. In particular, a single
primary light source can be used to decode the inventive barcode. In
particularly preferred embodiments, the present system and method is used
in applications to security systems, to the tracking of consumer items
such as jewelry, vehicles, or paper. In other particularly preferred
embodiments, the present system and method is used in applications for
biochemistry to track the location of biomolecules such as DNA sequences,
combinatorial chemistry, and genomics for encoding and probe identifiers.
