Now, a disposable device to identify aggressive breast cancers

WASHINGTON - Scientists have developed a new disposable device based on advances in microfluidics that may help identify advanced breast cancer patients who are candidates for therapy with the drug trastuzumab (Herceptin).

Aggressive breast cancers with poor prognosis typically have abnormal levels of the protein HER2 (the tyrosine kinase human epidermal growth factor receptor 2). The new elastomeric, rubber-like device is designed to efficiently capture cancer cells overexpressing HER2 in circulating blood.

Finding a way to identify these cells is medically relevant because HER2 positive patients with early breast cancer have been found to significantly benefit from treatment with Herceptin or trastuzumab, the humanized monoclonal antibody against HER2, which can lower recurrence risk by about half.

In the study Benjamin Thierry and colleagues at the Ian Wark Research Institute at the University developed a plastic-based disposable microfluidic device offering several improvements for capturing circulating tumor cells.

The device is designed to take advantage of the features of an organic silicone found in contact lenses and shampoos called polydimethylsiloxane (PDMS), which is compatible with soft molding techniques, transparent, and permeable to gasses.

The device is significantly easier and cheaper to make than the prior microfabricated one. The major challenge associated with PDMS use in biodiagnostic applications is its lack of chemical reactivity.

The team used a novel plasma-based polymerisation process to overcome that problem. The process creates a durable polymeric layer on the device’s surface containing a high number of reactive molecules, which can readily be used to attach proteins able to capture cancer cells but not normal blood cells.

With a commonly used breast cancer cell line (SK-BR-3) as a model for cells overexpressing HER2, Dr. Thierry’s device demonstrated an 80 percent immuno-capture efficacy of HER positive cells from full blood in model and validation studies.

“Microfluidic-based devices offer a unique opportunity to efficiently isolate CTCs from patient’s blood, thereby opening a window on the pathophysiology of cancer and its progression. We hope that our device will provide a fast, reliable and affordable methodology to establish HER2 status for breast cancer patients,” concluded Thierry.

The findings were described in the American Institute of Physics’ journal Biomicrofluidics. (ANI)