High-throughput PDT Screening Chip

In vitro efficacy assay is a routine prescreen step for anti cancer drug development including various showing up photosensitizers (drugs used in photodynamic therapy or PDT). As photodynamic therapy's action mechanism involves essential interactions among photosensitizer, oxygen and light, an in vitro test of photosensitizer requires controls of all three factors, and more detailed preclinical tests could provide better guidance for its potential optimum in-vivo protocols. In this project we use microfluidic platform for evaluating photosensitizer efficacy changes on various therapeutic factors including drug concentration, dissolved oxygen level, fluence (illumination dose), cell type, and incubation time. High throughput screening is realized with parallel on-going efficacy assay with vast cell arrays subject to on-chip factor gradient, either single therapeutic factor or combined multiple ones. Application with both free dye photosensitizer Methylene blue (MB) and new generation photosensitizer of multifunctional nanoparticle (NP) have been carried out. Different cell types (C6, DI TNC1, 9L, and MCF-7) are involved for showing different PDT efficacy response. We consider this microfluidic platform could provide a universal method for photosensitizer drug efficacy screening and help quickly set up a photosensitizer library with each drug's efficacy variance information and provide guidelines for patient treatment.

Figure 1: Schematics of the PDT screening chip.

Figure 2: Fabricated PDT screening chip filled with food day in each layer: gas layer (yellow), cell layer (red) and filter layer (green).

Figure 3: C6 cells after live/dead staining showing that viability changes according to both oxygen level gradient and MB concentration after PDT treatment on chip.

Related Publication
  1. X. Lou, G. Kim, Koo Lee, R. Kopelman, and E. Yoon. "Investigating Photodynamic Efficiency of Tumor Targeted Nanoparticular Photosensitizer Using Microfluidic Chips," in International Conference on Miniaturized Systems for Chemistry and Life Sciences (MicroTAS '11), 2011, pp. 2058-2060
  2. X. Lou, G. Kim, Y. Koo, R. Kopelman, E. Yoon, "High-throughput screening of photodynamic therapy (PDT) screening from multiple parameter assays of 1,000 different conditions in a single chip ," in International Conference on Miniaturized Systems for Chemistry and Life Sciences (MicroTAS '10), 2010, pp.719-721