Porous microwells for geometry-selective, large-scale microparticle arrays

Large-scale microparticle arrays (LSMA) are key for material science and bioengineering applications. However, previous approaches suffer from tradeoffs between scalability, precision, specificity, and versatility. Here, we present a porous microwell-based approach to create large-scale microparticle arrays with complex motifs. Microparticles are guided to and pushed into microwells by fluid flow through small open pores at the bottom of the porous well arrays. A scaling theory allows for the rational design of LSMAs to sort and array particles based on their size, shape or modulus. Sequential particle assembly allows for proximal and nested particle arrangements, as well as particle recollection and pattern transfer. We demonstrate the capabilities of the approach by means of three applications: high-throughput single-cell arrays; microenvironment fabrication for neutrophil chemotaxis; and complex, covert tags by the transfer of an upconversion nanocrystal laden LSMA.