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| For further information please contact Nader Pourmand |
Bio molecules with different sizes and structures can be uniquely identified
by the differential blockade of ionic current as they are interacting
with a nanopipette tip.
This novel technique can be used to distinguish between
various molecules passing through the nanopipette pore (approximately 20-50nm
diameter) creating characteristic blockade events (e.g. DNA labeled with
nanoparticles). Statistical or pattern recognition analysis of these events
produces parameters which are used in the identification process of target
molecules.
The nanopipette pore and the size of the particles can be scaled accordingly to result in the appropriate detectable signals. Our initial findings are a result of passing 24-base single stranded thiol-modified DNA molecules labeled with 10nm gold nanoparticles through a nanopipette and measuring the ionic current blockades. Statistical analysis of blockade events provided amplitudes and kinetic parameters to differentiate between particles with attached DNA and particles with no DNA.
Another use of this technique could be in a detection of protein targets interacting with functionalized nanopipette tip with a probe conjugate. Binding of the protein target to the nanopipette tip probe would result in a detectable event. The duration of this event could indicate the strength of the interaction and the amplitude of this event could indicate different protein complex conformations.
The nanopipette detection technique can provide not only tools for detection and identification of single molecules, but also deeper insight and understanding of the stochastic behavior of physical interactions of various molecules and the environment.