470020 A Shear-Enhanced CNT-DEP Nanosensor Platform for Ultra-Sensitive/Selective Protein Quantification with Tunable Dynamic Range: Overcoming Thermodynamic Limitations
Specific components of this new protein sensing platform include: 1. Accelerated DEP association of protein target with an Ab probe functionalized onto an electrode pair with high electric field; 2.Transportation and trapping of the second linking Ab probe functionalized CNTs with long-range DC electrophoresis and short-range AC DEP to the electrodes (lock); 3.Selective removal of assembled CNTs with non-targets by an optimized nanoshear protocol; 4.Conductance quantification of remaining bridging CNTs with target linkers (switch). Steps 1 and 2 involve rapidly driven dynamic events to prevent the captured targets from dissociating from the probe to reach the thermodynamic coverage. Optimized shear at the nm-high hydrodynamic slip length in step 3 irreversibly removes CNTs with non-targets due to the large Stokes drag of their high aspect-ratio cylindrical geometry. With only target-linked CNTs remaining, the digital conductance by electron-tunneling across the Ab-Ag-Ab complex allows us reach a detection limit of 100 molecules (100 aM). Irreversible capture and shearing also allow us to tune the dynamic range up to 100 billion (100 pM or 6 decades) by increasing the CNT number. We will also demonstrate carefully designed selectivity studies against non-targets with similar KD that report orders of magnitude discriminating factors. The data will be analyzed with a Langmuir association theory to quantify the deviation from thermodynamic equilibrium and how much shear reduces the dissociation barrier. Concentration factor and how DEP and electrophoresis reduces the transport time will also be estimated with collapsed and scaled impedance spectroscopy and conductance data.
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See more of this Group/Topical: 2016 Annual Meeting of the AES Electrophoresis Society