Fabrication of a silicon μDicer for uniform microdissection of tissue samples

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Generating uniform tissue microfragments is important in many applications, including disease diagnostics, drug screening, spatial-omics, and fundamental wound healing and tissue regeneration studies. Common mechanical dissection methods, such as manual mincing, are imprecise and result in fragments with a broad range in size. This work aims to develop a microscale dicing device, referred to as the “μDicer,” consisting of a hollow array of blades spaced hundreds of micrometers apart. A tissue pushed through this array is diced into many microfragments simultaneously. The focus of this paper is on the fabrication process of the μDicer using a combination of isotropic and anisotropic etching in silicon. A single silicon oxide etch mask is used in a dry silicon etcher for both a tapered etch to form the microblades, and an anisotropic etch to form the through-holes in the hollow blade array. The use of a single mask reduces the mask fabrication time by more than twofold compared with two-mask approaches often used to generate similar etch features. The etch parameters and the design of the etch mask control the blade angles and the edge profiles of the blades. Specifically, the incorporation of “notches” in the two-dimensional mask design generates three-dimensional microserrated features on the blade edges. A custom, open-source etching model is also developed to facilitate the prediction of the etch profiles. Finally, a proof-of-concept application of the μDicer to dissect soft materials and tissues is demonstrated.