Microfluidic system with light intensity filters facilitating the application of photodynamic therapy for high-throughput drug screening

Abstract

Background: : Photodynamic therapy utilizes light energy with a photosensitizer (a light-sensitive drug) to kill cancer cells through creation of singlet oxygen via light activation. When a photosensitizer is injected into the bloodstream and exposed to a specific wavelength of light, it generates oxygen to destroy or damage nearby cancer cells, while minimizing side effects on normal cells. Although photodynamic therapy is effective for treating cancer, various parameters, such as the optimum light intensity and photosensitizer dose, are currently poorly understood due to the complexity of conventional experimental schemes. Methods: : To effectively perform a simultaneous single parallel test for several different light irradiation conditions on each cell, a microfluidic device was developed to generate eight different intensities from a single light-emitting diode source, through eight different color dye concentrations functioning as light intensity filters. To show that this novel high-throughput microfluidic system can analyze the effects of various light intensities during photodynamic therapy, the optimum light intensities and photosensitizer doses were determined for two different cancer cell lines. Results: : Optimum light intensities and photosensitizer were determined for all cell lines. The photodynamic therapy effects in response to different irradiated light intensities were characterized by analyzing cell viability after photosensitizer treatment Conclusions: : The developed platform is capable of being used as a photodynamic therapy screening tool. The proposed platform provides a simple and robust way to optimize the combined parameters of light intensity and dosage for diverse types of cancer cells.