FIG. 1.

(a) Schematic of a biofunctionalized nanoslit (channel height h), with embedded probe-immobilized Au patterns, used as a real-time biosensor, where L_p is the sensor patch length and L_s is the single-pixel resolved sensor length. The drastic reduction of the target diffusion time (t) and the enhanced target-probe collision frequency, f_m = 1/(2t), using a nanoslit sensor may be apparent with the estimated t from top to bottom of the slit, using a diffusion constant D = 150 μm²/s for 25 mer DNA and a simple one-dimensional diffusion model, which is 33 s and 33 μs for h = 100 μm and 100 nm, respectively, with the corresponding f_m = 0.015 Hz and 15 kHz. (b) Photograph of a fabricated nanoslit sensor chip. Inset: fluorescence image of Cy3-labeled DNA solution flowing in the channel, on top of a 3 × 3 array of functionalized gold patterns (scale bar: 100 μm).