Cell morphology and nucleus deformation are important when circulating tumor cells break away from the primary tumor and migrate to a distant organ. Cells are sensitive to the microenvironment and respond to the cell-material interfaces. We fabricated TiO nanorod arrays with mesoscopic micro-nano interfaces through a two-step hydrothermal reaction method to induce severe changes in cell morphology and nucleus deformation. The average size of the microscale voids was increased from 5.1 to 10.5 μm when the hydrothermal etching time was increased from 3 to 10 h, whereas the average distances between voids were decreased from 0.88 to 0.40 μm. The nucleus of the MCF-7 cells on the TiO nanorod substrate that was etched for 10 h exhibited a significant deformation, because of the large size of the voids and the small distance between voids. Nucleus defromation was reversible during the cells proliferate process when the cells were cultured on the mesoscopic micro-nano interface.This reversible process was regulated by combining of the uniform pressure applied by the actin cap and the localized pressure applied by the actin underneath the nucleus. Cell morphology and nucleus shape interacted with each other to adapt to the microenvironment. This mesoscopic micro-nano interface provided a new insight into the cell-biomaterial interface to investigate cell behaviors.

We introduce a micropillar-based microfluidic device for efficient and rapid cancer cell capture. The microfluidic chip consists of two linear arrays of micropillars integrated with a herringbones flow-derived microstructure, and the separation distance between two adjacent micropillars is similar to the size of tumor cells. Cancer cells can be forced to come into contact with the micro-columns and are then captured by specific immune antibody-antigen interactions. Both previously published data and new available experimental data confirm the superiority of the proposed device. Different cancer cell lines were utilized to investigate the capture efficiency of our microfluidic device. MCF-7 cancer cells spiked into DMEM culture medium can be captured from a suspension with over 90% efficiency. The results of the present work provide a promising method for separation of rare cells, such as circulating tumor or fetal cells.

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