  DNA monolayers with inherent chirality play a pivotal role across various
domains, including biosensors, DNA chips, and bioelectronics. Nonetheless,
conventional DNA chiral monolayers, typically constructed from single-stranded
DNA (ssDNA) or double-stranded DNA (dsDNA), often lack structural orderliness
and design flexibility at the interface. Structural DNA nanotechnology emerges
as a promising solution to tackle these challenges. In this study, we present a
strategy for crafting highly adaptable twisted DNA origami-based chiral
monolayers. These structures exhibit distinct interfacial assembly
characteristics and effectively mitigate the structural disorder of dsDNA
monolayers, which is constrained by a limited persistence length of ~50 nm of
dsDNA. We highlight the spin-filtering capabilities of four representative DNA
origami-based chiral monolayers, demonstrating a maximal one-order-of-magnitude
increase in spin-filtering efficiency per unit area compared to conventional
dsDNA chiral monolayers. Intriguingly, our findings reveal that the
higher-order, tertiary, chiral structure of twisted DNA origami further
enhances the spin-filtering efficiency. This work paves the way for the
rational design of DNA chiral monolayers.
