A cheap and effective way to isolate cancer cells from the blood
Are freely circulating cancer cells caught on a rough surface?
Since metastases can give rise to secondary tumors, scientists are looking for ways to detect and isolate such cells for further study, the purpose of which is to better understand the process of metastasis, as well as to develop measures to prevent the progression of cancer. In a recent publication in the journal ACS Nano (Chen et al., Nanoroughened Surfaces for Efficient Capture of Circulating Tumor Cells without Using Capture Antibodies), scientists from the University of Michigan in Ann Arbor (USA) report on the development of a cheap technology that allows separating cancer cells using only the etched surface of a slide.
Unfortunately for scientists and to the great happiness of patients, such freely circulating malignant cells exist in scanty concentrations, which makes it even more difficult to extract them from the bloodstream for further research.
One of the most effective methods of capture is the use of specific antibodies that bind to their proteins on the cell surface. But antibodies are very expensive, and not all cancer cells have identical surface proteins (a more effective approach is to develop antibodies for each individual case of cancer, but this makes the method not only extremely expensive, but also very long).
In order to develop an alternative method, Jianping Fu and his colleagues from the University of Michigan tried to "play" with one important property characteristic of most types of malignant cells. Previously, it was repeatedly reported that cancer cells have a pronounced affinity for uneven surfaces. Various scientific groups have proposed using the same antibodies as a "texture" that would capture circulating cancer cells. In the work under consideration, Mr. Fu and his colleagues decided to get rid of expensive antibodies altogether and capture only on the basis of the affinity of malignant cells to rough surfaces.
The uneven glass surface was obtained using an inexpensive method of etching with active ions (the substrate is bombarded with charged ions). When scientists pipetted cervical cancer cells and breast cancer cells onto rough and smooth glass (see illustration), they clearly saw that cells of all types were preferably attached only to etched surfaces.
To compare the behavior of cancer cells and blood cells on a slide, scientists prepared mixtures containing different concentrations of white blood cells and breast cancer cells. As a result, in all cases, at least 95% of cancer cells "stuck" on the roughness of the etched surface. Finally, the logical final step was the use of a microfluidic device to determine the relative strength of cell adhesion to etched surfaces. In comparison with blood cells, cancer cells showed 100 times stronger adhesion.
Cancer cells of all types prefer to attach only to etched surfaces, avoiding smooth ones
(ACS illustration)
The refusal to use antibodies makes it possible to use this method of catching freely circulating cancer cells from a wide range of tumors, regardless of which molecules are expressed by their cell membranes.
Prepared based on Chemical & Engineering News: Capturing Cancer Cells With Rough Surfaces.
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