Early detection of cancer possible through a micro device

AN NUS-developed microchip has made it possible to extract cancer cells from blood – physically – and with high isolation efficiency and purity. A team from the Faculty of Engineering’s Division of Bioengineering and the NUS Graduate School for Integrative Sciences and Engineering, in collaboration with the Institute of Microelectronics, has invented a micro device for this purpose. These isolated cancer cells hold information on the development of the disease. Studying their characteristics would also reveal the progress of treatment and medication that the patient has undergone.

The invention snared the Merit Award (Open Category) at the Tan Kah Kee Young Inventors Awards 2009. Mr Tan Swee Jin, a PhD student submitted the winning work, MicroDevice for isolation of cancer cells from peripheral blood for cancer diagnostics, said he invented the device after reading numerous literature reviews on the cancer disease.

Commenting on what inspired him to work on the invention, Swee Jin who graduated from the NUS Faculty of Enginering with a degree in Mechanical Engieering, said: “The clinical significance of circulating cancer cells in blood gained prominence after studies showed that they correlated directly to the disease development and progression. My colleagues in the laboratory have been testing the physical properties of cancer cells and I could clearly see the differences manifested between cancer cells and blood constituents. So it makes sense to extract these cancer cells and study them in greater depth.”

His method is an alternative and easier way to separate cancer cells from blood. Said Swee Jin’s supervisor, Assoc Prof Lim Chwee Teck: “The use of biomarkers is one of the leading techniques used to detect cancer. However, the sensitivity of such tests varies from different cancer types and is dependent on the biomarkers used. Our method using the micro device allows us to study cancer cells more precisely as we are able to physically trap and retrieve them for further analysis. The method is non-invasive as getting blood samples does not involve surgery which conducting a tumour biopsy would require.  Furthermore, as compared to existing techniques, no staining or pre-treatment of the cells is required,” he said.

How the device works

The device acts like a sieve or a pacinko machine, where the stiffer cancer cells get trapped in crescent shaped structures while the softer erythrocytes and leukocytes readily pass through them. Pressure differential between the inlet and outlet of the device drives the flow of blood sample through the filtering system. Thus, cancer cells are “trapped” as they differ from blood cells in size and stiffness.

A major challenge for the team was to isolate low counts of cancer cells in blood without clogging the microdevice with unwanted cells. “Using simulation studies, we were able to better position the isolation structures that minimised the possibilities of clogging in the device. Using this technique, we attained high cell isolation efficiencies with enhanced isolation purity comparing with existing techniques,” said Swee Jin.

Currently, there is great interest from clinicians at the National Cancer Centre, Singapore to test this device on patients’ blood derived from different types of cancer.  Also, there are already several investors indicating interest in possibly commercialising this microdevice.