Microfluidics for biological measurements with single-molecule resolution

•Single-molecule (SM) analysis is critical for studying heterogeneous biological systems.•Microfluidics offers a wide range of tools for precise and efficient sample handling.•The combination of SM detection and microfluidics has facilitated many areas of life science research.•Applications of microfluidic SM detection are reviewed.•Topics range from macromolecule biophysics to genomic analysis. Single-molecule approaches in biology have been critical in studies ranging from the examination of physical properties of biological macromolecules to the extraction of genetic information from DNA. The variation intrinsic to many biological processes necessitates measurements with single-molecule resolution in order to accurately recapitulate population distributions. Microfluidic technology has proven to be useful in the facilitation and even enhancement of single-molecule studies because of the precise liquid handling, small volume manipulation, and high throughput capabilities of microfluidic devices. In this review we survey the microfluidic “toolbox” available to the single-molecule specialist and summarize some recent biological applications of single-molecule detection on chip.