Molecularly-targeted therapeutics and personalized medicine have dramatically increased the prognosis of patients suffering from cancer. However, tumor heterogeneity has limited the success of single drug treatment which led to the introduction of multiple therapeutic combinations. As such, multiple therapeutic combinations have required the development of new analytical methods capable of multiplexed high-throughput screening (HTS) technologies capable of examining both concentration and number of therapeutics. Droplet microfluidic devices has garnered significant interest to facilitate high-throughput, single cell analysis. One limitation of droplet generators is their ability to only assess a single input condition like concentration or number of drugs. To address this limitation, rare earth (RE)-doped nanoparticles were coupled with a microfluidic droplet trapping array for a novel approach at droplet tracking to visually assess different doses and drug combinations in the droplets. The β-hexagonal NaYF4 nanoparticles were doped with rare-earth emitters (Eu3+, Tb3+, Dy3+) which have a luminescence emission spectrum in the red, green and blue region upon UV excitation. An advantage of the RE-doped nanoparticles is that their excitation and emission spectra do not overlap with standard fluorophores thus allowing for both droplet tracking and quantification of cell viability or enzyme activity. This spectral independence was observed in (i) GFP-labeled HeLa cell, (ii) RFP-labeled MDA-MB-231 cells, and (iii) pre-killed MDA-MB-231 cells stained with Ethidium homodimer-1. Moreover, the RE-doped nanoparticles were confirmed to be biologically inert. Finally, a Python algorithm was developed to automatically distinguish droplets from cells, count cells in each droplet, and quantify cell viability to facilitate the single cell analysis in a high-throughput manner. The accuracy of this algorithm was compared with manual counting of cells, with a difference of ~2 percent. Thus, this work established the foundation for future applications using this technique in multiplexed droplet tracking to understand tumor heterogeneity through combinatorial therapies. The applications for this algorithm are numerous including fluorescence quantification, droplet tracking, and biomarker detection.

High-throughput droplet tracking and automated image analysis in microfluidic device

255th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.