Assembly of Multicomponent Structures from Hundreds of Micron-Scale Building Blocks Using Optical Tweezers

Date Published: August 17, 2021

The fabrication of three-dimensional (3D) microscale structures is critical for many applications, including strong and lightweight material development, medical device fabrication, microrobotics, and photonic applications. While 3D microfabrication has seen progress over the past decades, complex multicomponent integration with small or hierarchical feature sizes is still a challenge. Dr. Jeffrey Melzer and Dr. Euan McLeod have precisely fabricated 3D microstructures from two types of micron-scale building blocks linked by biochemical interactions using an optical positioning and linking (OPAL) platform based on optical tweezers technology. It is anticipated that OPAL will enable the assembly, augmentation, and repair of microstructures composed of specialty micro/nanomaterial building blocks to be used in new photonic, microfluidic, and biomedical devices. Read the published article.

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 Large-scale microassembly using optical tweezers. a Scanning electron microscope (SEM) image of a 3D periodic 8 × 8 × 7 simple cubic lattice consisting of alternating biotin-coated and streptavidin-coated 1 μm polystyrene spheres. Inset: 3D layout of the two components. b SEM image from (a) with overlaying spheres in red along the front, side, and top faces of the structure, which are used to estimate a mean absolute 3D positional error of 180 nm. c High-magnification SEM image of a corner of a 6 × 6 grid of alternating biotin- and streptavidin-coated 1 μm spheres. The streptavidin-coated spheres exhibit a rougher surface. d–f Optical microscope images of the full structure in (c). The biotin-coated spheres are green-fluorescent, while the streptavidin-coated spheres are red-fluorescent. The brightfield image is shown in (d), and the fluorescence image obtained using a FITC filter set is shown in (f). A mixed modality image (brightfield + fluorescence) is shown in (e).