Detection of Target ssDNA Using a Microfabricated Hall Magnetometer with Correlated Optical Readout
Figure 3
Sequence-specific two-strand DNA assembly and subsequent Hall detection of a single 344 nm nanobead. (a) Pictorial representation of two-strand DNA assembly, where the probe DNA (red) is complementary to the receptor DNA (blue). (b) Hall response data for the active (iv) and control Hall junction (ivc) plotted as Hall voltage versus time, where the drop in Hall voltage corresponds to the presence of a magnetic nanobead. (c) SEM was used to confirm that only one nanobead contributed significantly to the signal measured in (iv); scale bar = 2 μm. (d) The theoretical Hall device cross-sectional response for a single 344 nm SPM bead as a function of position from the center of the junction, where red indicates strongest change in voltage, aqua indicates weakest voltage change, and blue indicates a negative voltage readout. The noise floor for the device is outlined in black for reference.
