DNA Nanolithography Enables a Highly Ordered Recognition Interface in a Microfluidic Chip for the Efficient Capture and Release of Circulating Tumor Cells.

Microfluidic chips with nano-scale structures have shown great potential, but the fabrication and cost issues restrict their application. Herein, we propose a conceptually new "DNA nanolithography in a microfluidic chip" by using sub-10 nm three-dimensional DNA structures (TDNs) as frameworks with a pendant aptamer at the top vertex (ApTDN-Chip). The nano-scale framework ensures that the aptamer is in a highly ordered upright orientation, avoiding the undesired orientation or crowding effects caused by conventional microfluidic interface fabrication processes. Compared with a monovalent aptamer modified chip, the capture efficiency of ApTDN-Chip was enhanced nearly 60 % due to the highly precise dimension and rigid framework of TDNs. In addition, the scaffolds make DNase I more accessible to the aptamer with up to 83 % release efficiency and 91 % cell viability, which is fully compatible with downstream molecular analysis. Overall, this strategy provides a novel perspective on engineering nano-scaffolds to achieve a more ordered nano-topography of microfluidic chips.