A BIOCHIP which sieves cancer cells from the blood has been developed by a team of mechanical engineers from the National University Singapore.

Capturing the cells without damaging them - a feat considered very difficult until now - allows doctors to study the cancer and see how the disease has progressed.

After passing just two teaspoons of blood (10ml) through the micro device, experts can count the number of cancer cells in the blood stream via a microscope, and collect the cancer cells for further tests.

Other methods of capturing such cells involve magnetic separation and protein-coated collection devices, which can destroy them in the process.

Cancer cells are found in the blood stream when a cancer is malignant - the aggressive type of cancer.

They are not easy to isolate however, as 1ml of blood contains about 5 billion red cells and 7.4 million white blood cells, but only five or fewer cancer cells, in the early stages of illness.

These circulating cancer cells detach from the cancer and travel in the blood stream, attacking other parts of the body to form more tumors.

The new device, one-third the size of a 5 cent coin (5.1mm by 3.7mm), is creating a stir in the cancer research field. It has already bagged its inventor, doctoral student Tan Swee Jin, a merit prize in the Tan Kah Kee Young Inventors Awards this year.

Mr Tan told The Straits Times that he came up with the idea after being inspired by the work of cancer researchers.

'Their findings have shown that there are clear differences between cancer and blood cells,' he said.

Read the full report in Thursday's edition of The Straits Times.