This image shows the capture of cancer cells (green) by custom-shape microparticles(red). Using microparticles for cell isolation and detection is extremely important for cancer diagnostics (i.e. for capture of circulating tumor cells in the blood stream) as well as other biomedical applications. We are trying to understand how the physical parameters of microparticles – shape and stiffness – affect their ability to capture cells, to enable better design of such particles in the future.