Schematic illustrations of the present nanofluidic crystal based protein sensor and its signal enhancement. (a) Sensing principle of the present nanofluidic crystal; (b) equivalent electrical model of the sensing unit; (c) basic surface status, thrombin captured status, and signal enhancement status, from top to bottom; (d) corresponding I-V curves for three different surface statuses in (c).
The experimental setup and the chip. (a) The whole experimental system; (b) Photo of the micropore chip with a penny for comparison. Inserted is a SEM photo of the packed nanoparticles (from the pore-side). The scale bar is 5 μm.
Variation of conductance with time during the stabilization of nanofluidic crystal under 10 V bias.
Variation of the ionic current with time during electrophoresis loading of thrombin molecules. The current keeps stable in DI water without loading thrombin.
Conductance variation with thrombin concentration in DI water. The inserted photo shows a typical I-V curve. The error bars represent three independent tests.
Comparison of the conductance variations in the experiment group and three control groups.
Variation of the measured surface Zeta potentials (absolute values, all measured Zeta potentials were negative) and the calculated surface charge densities with the thrombin concentration. The columns (data on top) represented the ratios of the calculated surface charge density to the measured Zeta potential in each case, which theoretically should be the same.
Sequences of oligonucleotides (DNA/aptamers) used in the present work.
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