Dual fluorescence ratiometric technique for micromixing characterization
- 37 Downloads
To probe high-speed mixing within microfluidic devices, an imaging technique that uses fluorescent emissions as an indicator of fluorophore concentration has been developed. Given that fluorescent emission varies linearly with excitation intensity, higher powered excitation sources, such as lasers, must be used to collect sufficient emission information over short periods of time. However, since laser-based excitation sources tend to be spatially and temporally non-homogeneous, a ratiometric imaging technique is used to correct these fluctuations without removing concentration information. Image processing is used to determine the homogeneity of the ratio values and, by correlation to the concentration, the level of mixing for the whole sample can be determined. The accuracy of this technique is assessed by comparing experimental results to a parallel flow micromixer COMSOL simulation of the actual concentration and overlaying imaging results. The dual fluorescence ratiometric technique is accurate within 11% of the simulations. The technique is then used to characterize a serpentine droplet micromixer which uses chaotic advection to increase the rate of mixing throughout the sample. This system is characterized using four different oil flow rates for mixing measurements taken for three different height locations throughout the channel.
This work was supported by The Northeastern University start-up funds, and a NSF Award Grant CBET-1522841.
- Mayinger F, Bockhorn H, Mewes D et al (2010) Micro and macro mixing. Scientific Publishing Services, BerlinGoogle Scholar
- Tirandazi P, Hidrovo CH (2016) Generation of uniform liquid droplets in a microfluidic chip using a high-speed gaseous microflow. In: ASME 2016 14th international conference on nanochannels, microchannels, and minichannels, pp 1–6. https://doi.org/10.1115/ICNMM2016-8061
- Wang NS, Rinaudo P, McAvoy T (1988) Laser-induced fluorescnece monitoring of multicomponent aromatic amino acids. 196th Natl ACS MeetGoogle Scholar