Engineering 101

Pathology Labs on Chips Could Revolutionize Cancer Detection and Treatment

By Ruth Seeley

Early detection of all forms of cancer provides the best hope for successful treatment—if not eradication, then at least increased survival rates. But despite widespread education and the development of screening guidelines, many of the procedures are highly invasive and prohibitively expensive.

A new technology known as microfluidics promises portable, cheap devices that could not only enable widespread screening for early signs of cancer but also help to develop personalized treatments for patients, said Ciprian Iliescu, a researcher at IMT-Bucharest and co-author of a review of microfluidic methods for cancer analysis published in the journal Biomicrofluidics.

The devices, used to analyze bodily fluids, are as thin as a human hair. By isolating cells and exposing them to drug candidates, patient response can be predicted and tumor evolution in response to treatment can be easily tracked. The devices scan blood, saliva or urine for certain cells, proteins or tissue that are produced by tumors and then spread throughout the body.

The use of fluids as a liquid biopsy, instead of a conventional solid biopsy from a tumor, has many advantages. It is less invasive, reducing patient discomfort, and also provides information about hard-to-access tumors, such as in unborn children.

Because the biological clues, or biomarkers, of cancer end up in the bloodstream, a liquid biopsy can give insights into the genomic state of all cancer in the body, including at its primary site and if it has spread, or the “global molecular status of the patient.”

The biggest challenge is the diversity of cancer. Each of the more than 100 known cancers have their own biomarkers, which the authors classify into four categories: cellular aggregates (circulating tumor microemboli); free cells (circulating tumor cells, circulating endothelial progenitor cells and cancer stem cells); platelets and cellular vesicles (exosomes) and macro- and nanomolecules (nucleic acids and proteins).

A wide range of microfluidic devices are being designed to isolate these biomarkers, leveraging the boom in nanofabrication in recent decades. Complex structures, such as forked flow channels, pillars, spirals and pools, precisely sieve and control flow rates, while surfaces are lined with molecules that attract specific species. Some devices also use electrical, magnetic or acoustic fields to help select the biomarker target and even have smart, built-in electronic circuits for data processing.

There are already devices on the market, such as CellSearch, which isolate circulating tumor cells. However, more sensitive and faster systems are being developed for many different cancer biomarkers.

Combining more than one method may help with accuracy, although at the cost of speed. Sensitivity can also be improved by culturing the biomarkers to increase their concentration. Iliescu said the field has potential but is still in its infancy and that more clinical tests are needed to bring the technology to maturity.

Source: American Institute of Physics


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