Abstract

Digital Microfluidics For Single-Molecule Detection And Single Cell-Analysis

Elena Perez Ruiz, Senior Scientist, KU Leuven

Digital microfluidics emerged in the last years as a promising liquid handling technology for a wide variety of applications. Recently, DMF has been introduced as a novel platform to perform digital assays. In this type of assays, first specific bioreceptors are attached to microscopic magnetic particles and afterwards the target molecule is captured on the particle surface. Next, a secondary receptor and an enzymatic label are added, followed by the seeding and trapping of the microparticles in femtoliter-sized reaction wells. In these wells, once a fluorogenic substrate is added, the fluorescent signal remains confined, which allows for easy visualization of single DNA or protein molecules with standard fluorescence microscopy.

Similarly, the concept of microwell arrays integrated on a DMF platform has been exploited for trapping single cells and implementing cell-based studies. In this case individual yeast or bacterial cells are isolated in the micrometer-sized wells with or without the assistance of a magnetic particle. Subsequent monitoring of the fluorescently-labelled trapped cells allows conducting high-throughput dose-response cytotoxicity studies and screenings at the single-cell level.

Additionally, the DMF microwell array platform has been combined with optical tweezers, leading to a powerful bioanalytical tool, which enables controlled manipulation of individual targets. A major advantage of this tool is the possibility to retrieve individual targets, on which an interesting event was spotted, for post-analysis at the single molecule or single cell level.

The aforementioned applications illustrate the versatility of microwell arrays integrated on a DMF platform as a research tool to perform detection and analysis at the single molecule level in various domains of the life sciences.