Droplet-based microfluidic systems enable miniaturization of chemical reactions in femtoliter to picoliter volume compartments. Quantifying mixing dynamics of the reagents in droplets is critical to determine the system performance. In this Letter, we developed a two-photon excitation fluorescence lifetime imaging technique to quantitatively image the mixing dynamics in microfluidic droplets. A cross/autocorrelation method was used to reconstruct a high-quality fluorescence lifetime image of the droplet. The fluorescence decay was analyzed for accurate determination of the mixing ratio at each pixel of the image.
© 2011 Optical Society of America
Original Manuscript: March 9, 2011
Revised Manuscript: May 6, 2011
Manuscript Accepted: May 11, 2011
Published: June 7, 2011
Vol. 6, Iss. 7 Virtual Journal for Biomedical Optics
Yan Zeng, Liguo Jiang, Wei Zheng, Dong Li, Shuhuai Yao, and Jianan Y. Qu, "Quantitative imaging of mixing dynamics in microfluidic droplets using two-photon fluorescence lifetime imaging," Opt. Lett. 36, 2236-2238 (2011)