Figure 1.

Functionalized node-pore device assembly and measurement. (A) The basic node-pore platform consists of a glass substrate with predefined platinum electrodes and gold contact pads. (B) To functionalize the node-pore device with antibodies, a temporary polydimethylsiloxane (PDMS) mold embedded with N individual microchannels, corresponding to N functionalized segments (five are shown here), is positioned onto the substrate transverse to the direction of the ultimate node-pore channel. APTES, sulfo-EGS, Protein G, and antibodies are injected and incubated into the channels to functionalize and pattern the antibodies onto the substrate (C). (D) A slab of PDMS embedded with the node-pore is aligned directly on top of the functionalized substrate such that the channel is perpendicular to the patterned antibodies. (E) The completed node-pore device has functionalized antibodies in the channel between the nodes. (inset) A pseudocolored (ImageJ) fluorescent image of three different patterned antibodies (PE Mouse IgG1, κ Isotype Control (200 μg/mL), Brilliant Violet 421 Rat IgG1, κ isotype control (50 μg/mL), Alexa Fluor 647 Mouse IgG2b, κ Isotype Control (500 μg/mL), all from Biolegend) in a completed node-pore. Scale bar, 500 μm. (F) As a cell transits a node-pore functionalized with five antibodies (top), the modulated current pulse produced (bottom) reflects the interactions between cell surface markers and the functionalized segments. For the schematic shown, the cell expresses two markers that specifically interact with Antibodies 1 and 3, leading to longer transit-times, τ_Ab1 and τ_Ab3, in these segments as compared to the transit-times, τ_Ab2, τ_Ab4, and τ_Ab5, recorded when the cell traverses through the other segments of the node-pore.