Researchers at the Institute of Bioengineering and Nanotechnology (IBN) in Singapore have developed a miniaturized biochip for investigating the effect of drugs on cancer stem cells. The findings of the team led by IBN executive director Jackie Ying appears the journal Nano Today, and the technology is being commercialized by a spin-off company from the institute.
The efficacy of anti-cancer drugs against cancer stem cells is a key issue in treating the disease. Like other stem cells, cancer stem cells can produce and differentiate into different cell types, but if not eradicated, can also repopulate the tumor and lead to cancer recurrence. Cancer stem cells are also less resistant to chemotherapy.
In addition, attacking cancer stem cells raises another problem, their scarcity. They make up only about one percent of cancer sells. As a result. the study of cancer stem cells has been hampered by conventional drug screening methods that require large sample volumes.
To meet these challenges, the IBN team has developed a miniature biological assay called the Droplet Array to perform faster and less expensive drug screening on cancer stem cells that can use limited samples. Unlike traditional biological assays that require 2,500 to 5,000 cells for an analysis, the IBN device uses only 500 cells for a screening, which makes it feasible for cancer stem cells.
The Droplet Array is a flat, rectangular glass plate with a series of spots, each two millimeters in diameter. Samples are pipetted into these tiny spots, making them appear like droplets (pictured at top). The plate is then coated with a layer of oil to prevent evaporation and cross contamination between the sample droplets during the rinsing process. IBN has also developed a companion bench-top device to automate the rinsing process of the plate.
The IBN researchers used the Droplet Array to test drug responses of stem cells extracted from breast, liver and colon cancer cells. They found that chemotherapy drugs such as doxorubicin, which usually induce cell death in liver cancer cells, demonstrate little response from liver cancer stem cells. Likewise, stem cells from breast and colon tumors also have a greater ability to survive the effects of anti-cancer drugs.
The IBN team validated their lab findings with the Droplet Array with tests on mice. Stem cells and non-stem cells from liver tumors were implanted simultaneously into two different sets of mice. After six weeks, tumors formed in the mice implanted with cancer stem cells, while mice without stem cells did not develop tumors. Tumors extracted from the mice with stem cells also showed that they formed blood vessels, which confirms the self-renewal property of these cells.
The Droplet Array technology is currently being commercialized by an IBN spin-off company, Curiox Biosystems Pte Ltd, and marketed under the brand-name DropArray. Curiox Biosystems is IBN’s first spin-off enterprise, founded in 2007 by IBN researchers, who had devised an earlier version of the technology.
Read more:
- Lab-On-A-Chip Device Developed to Test for Flu Viruses
- NIH Funds Study of Chemical Effects on Adult Stem Cells
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