Picture of a sensor with definition of dimensions. The bias current I is applied through the arms in the x-direction, while the potential difference Vy is measured across the y-direction.
In-phase second harmonic signal measured at the indicated values of vs. time t after injection of the bead suspension for (a) Ocean Nanotech beads with nominal diameters of 10 nm, 25 nm, and 40 nm and (b) Micromod beads with nominal diameters of 80 nm, 130 nm, and 250 nm. In the final part of each experiment, the bead suspension is washed out of the channel.
In-phase (top) and out-of-phase (bottom) corrected second harmonic sensor signals. The solid lines are fits of the Cole-Cole model to the data.
In-phase (top) and out-of-phase (bottom) corrected second harmonic sensor signal from Fig. 3 normalized to their respective maximum values. The solid lines are fits of the Cole-Cole model to the data.
Standard deviation of baseline in-phase sensor signal at for the six values of used for the different bead types.
Values of Dh , α, , and obtained from Cole-Cole fits to the frequency sweeps initiated 20 min after injection of the bead suspensions. The numbers in parenthesis after the fitting parameter are 95% uncertainties. The last two columns list the molar concentration c of each bead type in nM and the peak sensor signal normalized with the bead molar concentration . is the theoretical limit of detection calculated by .
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