de Rutte, J. | bioRxiv Science

bioRxiv2020

Monodisperse drops templated by 3D-structured microparticles

The ability to create uniform sub-nanoliter compartments using microfluidic control has enabled new approaches for analysis of single cells and molecules. However, specialized instruments or expertise have been required, slowing the adoption of these cutting-edge applications. Here, we show that 3D-structured microparticles with sculpted surface chemistries template uniformly-sized aqueous drops when simply mixed with two immiscible fluid phases. In contrast to traditional emulsions, particle-templated drops of a controlled volume occupy a minimum in the interfacial energy of the system, such that a stable monodisperse state results with simple and reproducible formation conditions. We describe techniques to manufacture microscale drop-carrier particles and show that emulsions created with these particles prevent molecular exchange, concentrating reactions within the drops, laying a foundation for sensitive compartmentalized assays with minimal instrumentation.

bioengineering↗

bioRxiv2020

Massively parallel encapsulation of single cells with structured microparticles and secretion-based flow sorting

Techniques to analyze and sort single cells based on functional outputs, such as secreted products, have the potential to transform our understanding of cellular biology, as well as accelerate the development of next generation cell and antibody therapies. However, secreted molecules rapidly diffuse away from cells, and analysis of these products requires specialized equipment and expertise to compartmentalize individual cells and capture their secretions. Herein we demonstrate the use of suspendable microcontainers to sort single viable cells based on their secreted products at high-throughput using only commonly accessible laboratory infrastructure. Our microparticles act as solid supports which facilitate cell attachment, partition uniform aqueous compartments, and capture secreted proteins. Using this platform, we demonstrate high-throughput screening of stably- and transiently-transfected producer cells based on relative IgG production as well as screening of B lymphocytes and hybridomas based on antigen-specific antibody production using commercially available flow sorters. Leveraging the high-speed sorting capabilities of standard sorters, we sorted >1,000,000 events in less than an hour. The reported microparticles can be easily stored, and distributed as a consumable reagent amongst researchers, democratizing access to high-throughput functional cell screening.

bioengineering↗