Automated Microfluidic Droplet-Based Sample Chopper for Detection of Small Fluorescence Differences Using Lock-In Analysis.

ABSTRACT: Fluorescence is widely used for small-volume analysis and is a primary tool for on-chip detection in microfluidic devices, yet additional expertise, more elaborate optics, and phase-locked detectors are needed for ultrasensitive measurements. Recently, we designed a microfluidic analog to an optical beam chopper (μChopper) that alternated formation of picoliter volume sample and reference droplets. Without complex optics, the device negated large signal drifts (1/f noise), allowing absorbance detection in a mere 27 μm optical path. Here, we extend the μChopper concept to fluorescence detection with standard wide-field microscope optics. Precision of droplet control in the μChopper was improved by automation with pneumatic valves, allowing fluorescence measurements to be strictly phase lock

SUBMITTER: Negou JT 

PROVIDER: S-EPMC5789453 | biostudies-literature | 2017 Jun

REPOSITORIES: biostudies-literature