Programming 3D morphing actions of DNA-Linked Nanoparticle Films
Active materials that can undergo dynamic structural changes are of great interest in diverse areas of emerging science and technology including microrobotics, smart sensors, and medical devices. Here, we adopted a combination of bottom-up DNA-directed self-assembly and top-down photothermal patterning to fabricate free-standing nanoparticle films with vertical and lateral heterogeneity, which can undergo complex but precisely controlled shape transformations. Illuminating light on a DNA-linked nanoparticle film resulted in the removal of nanoparticles from the illuminated area owing to the efficient photothermal effect of gold nanoparticles, leaving photo-induced patterns on the nanoparticle film (Figure 1). Free-standing films with arbitrary shapes and patterns were readily fabricated on demand by the direct photothermal writing and subsequent removal of a sacrificial bottom layer. These photopatterned films exhibited complex and directional shape transformations according to their lateral patterns, depth profiles, and DNA sequences (Figure 2). The dynamic assemblies reported here are distinct from existing systems in that a single nanoparticle film can be designed to exhibit various morphing actions depending on the DNA sequences and etching patterns, which can lead to robot-like devices displaying higher order morphing actions.
Figure 2. (a-d) Schematics and optical microscope images of a single-patterned film (a) and double-patterned films (b-d) with two line (b), 45° tilted stripe (c) and −45° tilted stripe (d) patterns relative to the long axis of the film in the top domain. (e-h) Schematics and optical microscope images of shape-changing behaviors of photopatterned free-standing films.
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Jongwook Kim, Sunghee Lee, Jisu Choi, Kyungnae Baek, Tae Soup Shim, Jerome Kartham Hyun, So-Jung Park, Shape-Changing DNA-Linked Nanoparticle Films Dictated by Lateral and Vertical Patterns, ADVANCED MATERIALS, Volume 34, Issue13, April, 2022