  We present a facile desktop fabrication method for origami-based nano-gap
indium tin oxide (ITO) electrokinetic particle traps, providing a simplified
approach compared to traditional lithographic techniques and effectively
trapping of nanoparticles. Our approach involves bending ITO thin films on
optically transparent polyethylene terephthalate (PET), creating an array of
parallel nano-gaps. By strategically introducing weak points through cut-sharp
edges, we successfully controlled the spread of nano-cracks. A single crack
spanning the constriction width and splitting the conductive layers forms a
nano-gap that can effectively trap small nanoparticles after applying an
alternating electric potential across the nanogap. We analyze the conditions
for reversible trapping and optimal performance of the nano-gap ITO electrodes
with optical microscopy and electrokinetic impedance spectroscopy. Our findings
highlight the potential of this facile fabrication method for the use of ITO at
active electro-actuated traps in microfluidic systems.
