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DNA origami has been widely used to construct nanophotonic structures due to its unparallel capability in assembling photonic nanomaterials with nanometer precision. Nevertheless, the majority of fabricated fluorescence‐based nanophotonic systems so far operate in the ultraviolet‐visible (UV‐Vis) region, which are accompanied by limitations of shallow penetration and potential light damage. Herein, we constructed a reconfigurable nanophotonic heterostructure by integrating an upconversion nanoparticle (UCNP) and a gold nanorod (AuNR) on a DNA origami switch (DOS) template. With the unique anti‐Stokes luminescence of UCNP whose excitation wavelength is mostly located in the near‐infrared (NIR) region, the obtained reconfigurable nanophotonic system can be excited by 980 laser light and generates visible light emission. In our nanophotonic system, the DNA origami template serves as a switch to reversibly tune the optical properties of UCNP. The construction of this nanophotonic heterostructure expands the toolbox of DNA origami‐based nanophotonic systems that may hold great potential in optical biosensing and imaging. [ABSTRACT FROM AUTHOR]

DNA origami enables the manipulation of objects at nanoscale, and demonstrates unprecedented versatility for fabricating both static and dynamic nanostructures. In this work, we introduce a new strategy for transferring modular reconfigurable DNA nanostructures from two‐dimensional to three‐dimensional. A 2D DNA sheet could be modularized into connected parts (e.g. two, three, and four parts in this work), which can be independently transformed between two conformations with a few DNA "trigger" strands. More interestingly, the transformation of the connected 2D modules can lead to the controlled, resettable structural conversion of a 2D sheet to a 3D architecture, due to the constraints induced by the connections between the 2D modules. This new approach can provide an efficient mean for constructing programmable, higher‐order, and complex DNA objects, as well as sophisticated dynamic substrates for various applications. [ABSTRACT FROM AUTHOR]

DNA‐modified lanthanide‐doped upconversion nanoparticles (DNA‐UCNPs) that combine the functions of DNA and the optical features of UCNPs have shown great promise in a wide range of fields. However, challenges remain in precisely tethering and orienting the DNA strands on the UCNP surface. Herein, we systematically investigate the sequence dependence of DNAs in their interactions with UCNPs, and reveal that poly‐cytosine (poly‐C) has high affinity for the UCNP surface. A general approach to synthesize monodispersed DNA‐UCNP conjugates is developed using poly‐C‐containing diblock DNA strands. The poly‐C segment of the DNA strand binds to the surfaces of UCNPs and the second segment is oriented perpendicularly on the UCNP surface, making the DNA‐UCNPs highly stable and monodispersed in aqueous solution. The dense layer of DNA on the UCNP surface enables the programmable assembly of UCNPs with other DNA‐functionalized nanoparticles or DNA origamis through hybridization, resulting in the formation of well‐organized complex structures. [ABSTRACT FROM AUTHOR]