Detection and Quantification of Genes and Carbon Nanotubes

This technology is based on a magnetic bead/quantum dot/nanoparticle system.  In short, two sets of single stranded DNA (ssDNA), one tagged with a quantum dot and another tied to a magnetic bead decorated with different quantum dots, are introduced into a sample.   For gene detection, both sets of ssDNA are designed to bind to the target DNA.  For carbon nanotube detection, the ssDNA strands are designed to specifically interact with the CNTs (see figure).  The targets can then be separated from the sample using a magnetic field, and then quantified using the quantum dot interactions.   The quantum dot fluorescence demonstrates extreme brightness, allowing for high sensitivity, and resistance to photo-bleaching, which makes the method very robust.  Further, the method has been shown to be resistant to compounds that inhibit other methods such as PCR, indicating the potential of this method for in situ application.  Finally, since ssDNA specifically interact with CNTs, it is able to differentiate CNTs from other carbon compounds, unlike traditional carbon chemistry or molecular weight based methods.

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