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Circulating Tumor Cell Filter

Cancers can metastasize when cells shed from a primary tumor and enter the blood stream. I developed a diagnostic tool to isolate these circulating tumor cells and measure their concentration. The device is a microfilter with actively controllable pore size, allowing the operator to release captured cells for collection downstream. This project was developed as part of my Master's degree at UBC. I published a paper on the device that you can read here. I go into more detail on the same device in my MASc thesis.

The metastatic process. Circulating tumor cells may be arrested in the microvasculature due to size restriction. Examples of cells arrested in the capillaries of muscle and liver are shown on the right. Image from Chambers et. al., Nature Reviews Cancer 2002

The ability to isolate and count circulating tumor cells (CTCs) in blood would provide a valuable diagnostic marker to oncologists and an important sample source to biologists studying the metastatic process. Despite more than a decade of research and development there exists no satisfactory solution for isolating and enumerating circulating tumor cells in blood.

Our approach uses physical filtration, relying on the supposition that CTCs will be larger and/or more rigid than typical blood cells, a hypothesis supported by the arrest of CTCs observed in the microvasculature.

An ideal filtration system should be inexpensive, biocompatible, optically transparent, and should support features on the micron length scale as cells are typically ~10um in diameter. To meet these requirements, we turned to microfluidic technology.

Below is a video of my microfluidic filter in action. The device filters a mixture of white blood cells (fluorescing blue) and cultured bladder cancer cells (fluorescing green). I'll discuss the process in more detail here.

Microscopy video showing a mixture of cells being separated by the device. I suggest you switch to fullscreen to better see the cells.