Development of a dual fluorescence system for simultaneous detection of two cell populations in a 3D coculture

A dual fluorescence system consisting of enhanced green fluorescent protein (EGFP) and red fluorescent protein (Ds-red) signals was developed for monitoring cellular activities. For system validation, MCF-7 breast cancer cells were engineered to express EGFP and Ds-red, respectively. Cells were cultured in three-dimensional (3D) polymer-based scaffolds on a 40-microbioreactor platform (40-MBR) with real-time monitoring of fluorescence signals without significant background fluorescence noises from culture medium and 3D scaffold. The fluorescence kinetics study showed that both EGFP and Ds-red signals in the 3D coculture could be simultaneously detected without interference with each other. The cytotoxicity study of tamoxifen and the survivin promoter test of doxorubicin demonstrated that both EGFP and Ds-red signals provided high sensitivity to evaluate drug effectiveness. These studies suggested that the novel dual fluorescence system could provide a simple, real-time, and rapid cell detection in 3D coculture assay, which could be used for in vitro high throughput drug screening.