Photodynamic therapy (PDT), or photochemotherapy, uses light sensitive chemicals called photosensitizers to attack tumors with high accuracy. This requires adding oxygen, the drug, and shining light precisely on the target being attacked, which is difficult to balance out since three variables are involved.
Now researchers at University of Michigan have developed a tiny 5mm x 5mm chip that can test out PDT reactions at high rate, which will hopefully significantly improve how PDT is applied in clinical use. The chip allows precise control of the mixing of the photosensitizer, oxygen, and light. Specifically, there are over 1000 tiny compartments on the chip with cancer cells being grown inside. Each of the compartments can be set at a different combination of the three variables and the effectiveness of how the cancer cells are killed is analyzed using live/dead fluorescence imaging.
From the study abstract in Lab on a Chip:
The entire screening assay takes only 1 hour, and the collected PDT outcomes (cell viability) for combinatorial screening are analysed and reported as traditional dose–response curves or 3D bubble charts using custom software. As a proof of concept, methylene blue is adopted as a photosensitizer and its drug efficacy on C6 glioma cells has been successfully evaluated for a total of 324 PDT conditions using the fabricated chip. This platform can facilitate not only the development of new photosensitizers but also the optimization of current PDT protocols.
Study in Lab on a Chip: A high-throughput photodynamic therapy screening platform with on-chip control of multiple microenvironmental factors
University of Michigan: Biochips for better cancer therapy