470077 High Throughput Cell Screening Via Luminescent Nanoparticles in a Microfluidic Device
Specifically, this work focuses on the viability of cells in the presence of the upconversion nanoparticles, NaYF4 core-shell particles. The rare earth emitter ions (Er3+ or Tm3+) are located in the core while the Yb3+ sensitizer is doped in the shell layer. The core particles are synthesized using a hydrothermal growth process with growth control between 40-500 nm. Afterwards, a shell layer is deposited using a sol-gel method for shell thickness up to 30 nm. The particles were shown to have an upconversion luminescence emission in the blue, green, and red spectral region upon excitation with 980 nm light allowing for the barcoding of three different treatment protocols. The ratio of intensity of the different emission peaks were engineered through the dopant type, concentrations, and location within the core-shell structure. As a proof-of-concept, combinations of one, two, and three different types of nanoparticles were encapsulated in aqueous droplets in the array to demonstrate the ability to selective tag individual droplets. In order to determine the applicability of the nanoparticles as a means for droplet barcoding, viability studies were performed using different sized nanoparticles across a range of concentrations in several model cancer cells lines including HeLa, OPM2, THP-1, and HCT116 cells. This work provides the technological first step for a novel, antibody-free method to barcoding droplets to increase the throughput and utility of microfluidic droplet trapping arrays as a technique for personalized medicine.