Three-dimensional microscale hanging drop arrays with geometric control for drug screening and live tissue imaging.

Existing three-dimensional (3D) culture techniques are limited by trade-offs between throughput, capacity for high-resolution imaging in living state, and geometric control. Here, we introduce a modular microscale hanging drop culture where simple design elements allow high replicates for drug screening, direct on-chip real-time or high-resolution confocal microscopy, and geometric control in 3D. Thousands of spheroids can be formed on our microchip in a single step and without any selective pressure from specific matrices.

Simultaneous time-varying viscosity, elasticity, and mass measurements of single adherent cancer cells across cell cycle.

Biophysical studies on single cells have linked cell mechanics to physiology, functionality and disease. Evaluation of mass and viscoelasticity versus cell cycle can provide further insights into cell cycle progression and the uncontrolled proliferation of cancer. Using our pedestal microelectromechanical systems resonant sensors, we have developed a non-contact interferometric measurement technique that simultaneously tracks the dynamic changes in the viscoelastic moduli and mass of adherent colon (HT-29) and breast cancer (MCF-7) cells from the interphase through mitosis and then to the cytokinesis stages of their growth cycle.

Optomechanical microrheology of single adherent cancer cells.

There is a close relationship between the mechanical properties of cells and their physiological function. Non-invasive measurements of the physical properties of cells, especially of adherent cells, are challenging to perform. Through a non-contact optical interferometric technique, we measure and combine the phase, amplitude, and frequency of vibrating silicon pedestal micromechanical resonant sensors to quantify the "loss tangent" of individual adherent human colon cancer cells (HT-29).

Evidence of differential mass change rates between human breast cancer cell lines in culture.

Investigating the growth signatures of single cells will determine how cell growth is regulated and cell size is maintained. The ability to precisely measure such changes and alterations in cell size and cell mass could be important for applications in cancer and drug screening. Here, we measure the mass growth rate of individual benign (MCF-10A), non-invasive (MCF-7), and highly-invasive malignant (MDA-MB-231) breast cancer cells.