Capturing the elusive circulating tumor cells (CTC) in whole blood is a major goal in medical science, potentially allowing for early detection and monitoring of a variety of cancers. Efficient and effective, technologically advanced capture techniques must be employed in order for CTC capture to be a cost effective option for early detection, as well as to minimize damage to the captured cells. Recently, microfluidic devices have been the focus of much research and development, and have had much success in the field of CTC capture. In the past we’ve covered CTC capture microfluidic chips with a >90% efficiency, and chips designed purely for separation of white blood cells from whole blood. However, we have yet to cover an efficient and effective chip designed for CTC capture. Now researchers at University of Michigan have created a microfluidic approach that may overcome some of the downsides of existing technology.
The new technology relies on gold particles in the shape of flowers that attract graphene oxide nanosheets to stick to them. In turn, the graphene oxide promotes growth of molecular chains that grab onto CTCs. The team tested the technology on samples taken from pancreatic, breast and lung cancer patients, and showed that their technology delivers high sensitivity of detection at a low concentration of CTCs in a given sample.
To test the device, the team ran one-milliliter samples of blood through the chip’s thin chamber. Even when they had added just three-to-five cancer cells to the 5-10 billion blood cells, the chip was able to capture all of the cells in the sample half the time, with an average of 73 percent over 10 trials.
The team counted the captured cancer cells by tagging them with fluorescent molecules and viewing them through a microscope. These tags made the cancer cells easy to distinguish from accidentally caught blood cells. They also grew breast cancer cells over six days, using an electron microscope to see how they spread across the gold flowers.
Study in Nature Nanotechnology: Sensitive capture of circulating tumour cells by functionalized graphene oxide nanosheets
U of Michigan: Liquid biopsy could improve cancer diagnosis and treatment