(1026-A) Automated nanoliter droplet selection and collection device for micro droplet arrays

Abstract: Droplet microarray platforms have become increasingly important tools in the fields of biological and chemical applications due to their ability to miniaturize and parallelize experimental processes. These platforms enable high-throughput screening and analysis of small samples, including single cells and biomolecules. However, the handling of nanoliter volumes on open droplet microarray platforms remains a significant bottleneck. The reduced volumes of these droplets make them difficult to handle manually, and traditional laboratory equipment is often unable to address this issue. For instance, in drug screening, the use of droplet microarrays enables the screening of large libraries of compounds with minimal sample consumption, but their handling remains a challenge when analysing samples due to the small volumes involved.
To address this need, we developed an automated solution for the manipulation of multiple nanodroplets on Droplet Microarrays platforms using open-source components. Our approach involves the use of a removable fused silica capillary that acts as a nozzle for droplet selection and collection by a syringe pump. This design enables the collection and repositioning of nanodroplets within and between different microdroplet arrays, ranging from 50 to 300 nl, with a droplet handling volume loss rate of 3%. In addition, the removable fused silica capillary allows the bulk and selective collection of multiple nanodroplets in approximately 1 second per nanodroplet, without any intermixing. This feature enables the storage, transport, and dosing of nanodroplets to other laboratory devices, such as LC-MS, facilitating downstream analysis.
Our study presents a cost-effective and customizable solution for multiple nanodroplets manipulation, which represents a step forward in the field of Droplet Microarrays platforms. The automated nanoliter droplet selection and collection device has the potential to overcome the "Chip-to-World" obstacle, assisting droplet microarrays to be used in a broad range of applications, such as high-throughput assays for drug screening, omics, and combinatorial chemistry.