3D nanofabrication by volumetric deposition and controlled shrinkage of patterned scaffolds

Abstract

Lithographic nanofabrication is often limited to successive fabrication of two-dimensional layers. We present a strategy for the direct assembly of three-dimensional nanomaterials consisting of metals, semiconductors, and biomolecules arranged in virtually any three-dimensional geometry. We use hydrogels as scaffolds for volumetric deposition of materials at defined points in space. We then optically pattern these scaffolds in three dimensions, attach one or more functional materials, and then shrink and dehydrate them in a controlled way to achieve nanoscale feature sizes in a solid substrate. We demonstrate this process, Implosion Fabrication (ImpFab), by directly writing highly conductive, 3D silver nanostructures within an acrylic scaffold using a volumetric silver deposition process, achieving resolutions in the tens of nanometers and complex, non-self-supporting 3D geometries of interest for optical metamaterials.

Polymer Networks: From Plastics and Gels to Porous Frameworks

“…This swelling leads to physical magnification of the specimen, enabling routine imaging of objects that were closer than the optical diffraction limit prior to swelling . Recently, the same group applied the inverse of this concept to nanofabrication: micron‐scale patterns embedded in hydrogels were reduced down to the nanoscale upon dehydration/shrinkage of the hydrogels by up to 10‐fold . Finally, various ways of controlling network swelling have led to recent developments of shape‐morphing materials, which rely on anisotropic swelling behaviors within polymer networks.…”

“…[140] Recently,t he same group applied the inverse of this concept to nanofabrication:m icron-scale patterns embedded in hydrogels were reduced down to the nanoscale upon dehydration/shrinkage of the hydrogels by up to 10-fold. [141] Finally,v arious ways of controlling network swelling have led to recent developments of shape-morphing materials, [142][143][144] which rely on anisotropic swelling behaviors within polymer networks.D etails of these methods can be found in recent reviews. [145,146] It should be noted that the swelling of polymer networks provides evidence for their porosity (i.e., void space in am aterial that can accommodate guest molecules such as solvent).…”

Polymernetzwerke: Von Kunststoffen und Gelen zu porösen Gerüsten

“…Diese Quellung führt zur physikalischen Vergrößerung der Probe und ermöglicht damit die routinemäßige Abbildung von Objekten, die vor der Quellung dichter beieinander liegen als die optische Beugungsgrenze . Kürzlich verfolgte die gleiche Gruppe den umgekehrten Ansatz bei der Nanofertigung: In Hydrogelen eingebettete Strukturen im Mikrometermaßstab wurden durch die Dehydratisierung und Schrumpfung der Hydrogele um bis den Faktor 10, d. h. auf den Nanomaßstab verkleinert . Darüber hinaus haben verschiedene Methoden zur Steuerung der Quellung von Netzwerken zur Entwicklung formverändernder Materialien geführt, die auf dem anisotropen Quellungsverhalten von Polymernetzwerken beruhen.…”

“…[140] Kürzlich verfolgte die gleiche Gruppe den umgekehrten Ansatz bei der Nanofertigung:I nH ydrogelen eingebettete Strukturen im Mikrometermaßstab wurden durch die Dehydratisierung und Schrumpfung der Hydrogele um bis den Faktor 10, d. h. auf den Nanomaßstab verkleinert. [141] Darüber hinaus haben verschiedene Methoden zur Steuerung der Quellung von Netzwerken zur Entwicklung formverändernder Materialien geführt, [142][143][144] die auf dem anisotropen Quellungsverhalten von Polymernetzwerken beruhen. Details dieser Methoden sind in neueren Übersichtsartikeln zu finden.…”

Soft Ring‐Shaped Cellu‐Robots with Simultaneous Locomotion in Batches

“…To reconfigure complex artificial 3D tissue surrogates in vitro, various biofabrication strategies have been developed including forming cell‐free scaffolds first or printing cells with materials simultaneously . Using 3D bioprinting strategies, cell composition and positioning can be adjusted in a large scale and at a relatively high resolution to form complex architectures . However, in the previous reported 3D bioprinting methods which use exogenous materials as the medium to load cells and frame the final spatial structures, as a result, the cell density may be limited by the external surrounding materials .…”