We employed direct-current electric fields (dcEFs) to modulate the chemotaxis of lung cancer cells in a microfluidic cell culture device that incorporates both stable concentration gradients and dcEFs. We found that the chemotaxis induced by a 0.5 lM/mm concentration gradient of epidermal growth factor can be nearly compensated by a 360 mV/mm dcEF. When the effect of chemical stimulation was balanced by the electrical drive, the cells migrated randomly, and the path lengths were largely reduced. We also demonstrated electrically modulated chemotaxis of two types of lung cancer cells with opposite directions of electrotaxis in this device. V C 2014 AIP Publishing LLC. [http://dx
BackgroundCell membranes exhibit abundant types of responses to external stimulations. Intuitively, membrane topography should be sensitive to changes of physical or chemical factors in the microenvironment. We employed the non-interferometric wide-field optical profilometry (NIWOP) technique to quantify the membrane roughness of living neuroblastoma cells under various treatments that could change the mechanical properties of the cells.ResultsThe membrane roughness was reduced as the neuroblastoma cell was treated with paclitaxel, which increases cellular stiffness by translocating microtubules toward the cell membranes. The treatment of positively charged gold nanoparticles (AuNPs) showed a similar effect. In contrast, the negatively charged AuNPs did not cause significant changes of the membrane roughness. We also checked the membrane roughness of fixed cells by using scanning electron microscopy (SEM) and confirmed that the membrane roughness could be regarded as a parameter reflecting cellular mechanical properties. Finally, we monitored the temporal variations of the membrane roughness under the treatment with a hypertonic solution (75 mM sucrose in the culture medium). The membrane roughness was increased within 1 h but returned to the original level after 2 h.ConclusionsThe results in the present study suggest that the optical measurement on membrane roughness can be regarded as a label-free method to monitor the changes in cell mechanical properties or binding properties of nanoparticles on cell surface. Because the cells were left untouched during the measurement, further tests about cell viability or drug efficacy can be done on the same specimen. Membrane roughness could thus provide a quick screening for new chemical or physical treatments on neuronal cells.
Using a cell culture chip with a deformable substrate driven by a hydraulic force, we investigated the motility of cancer cells affected by myofibroblasts undergoing cyclic tensile strain (CTS). CTS reduced both the expression of α-smooth muscle actin in the myofibroblast and the ability of the myofibroblast to accelerate cancer cell migration. However, with the treatment of a pro-inflammatory factor interleukin-1β on the myofibroblasts, the effects of CTS on the myofibroblast were diminished. This result suggests an antagonism between mechanical and chemical stimulations on mediating cancer metastasis by the stromal myofibroblast.
Abstract:We used a spatial light modulator to project an optical micropattern of 473 nm light with a quartic intensity gradient on a single lung cancer cell. We observed that the intracellular amounts of reactive oxygen species (ROS) of the cancer cells were proportional to the intensity of the blue light, and the blue light intensity gradients could drive directional cell migration. This optically induced directional cell migration was inhibited by a ROS scavenger in the culture medium in a dosedependent manner. In contrast, the ROS levels in fibroblasts were saturated by the blue light at low intensity and therefore the fibroblasts did not exhibit directional migration in the intensity gradient.
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