Biophysical Society Thematic Meeting - June 28-July 1, 2015

New Biological Frontiers Illuminated by Molecular Sensors and Actuators

Poster Abstracts

36-POS Board 36 Potassium-Mediated Tumor Invasion: A Mathematical Model Kiran George, Malathi Raman , Krishnan Jayaraman. Annamalai University, Annamalai Nagar, India.

The cancer cell invasion of tissue appears to be a complex biological process during which cell migration occurs through the extracellular matrix. It engages the potassium channels to regulate the behavior of cancer cell such as proliferation and migration through both canonical and non- canonical ion permeation functions. The pharmacological strategies, in view of their cell surface localization and well- known pharmacology target potassium channel and prove to be a promising therapeutics for cancer. The paper proposes a hybrid discrete-continuum multiscale model to study the early growth of solid tumors and their ability to degrade and migrate into the surrounding extracellular matrix. It models the cancer cells as discrete individual entities to interact with each other sing a potential function. The theory involves partial differential equations to model the spatio-temporal dynamics of the other variables that includes extracellular matrix, matrix degrading enzymes and potassium concentration. 37-POS Board 37 Optomechanical Actuators for Controlling Mechanotransduction in Living Cells Khalid Salaita 1,2 . 1 Emory University, Atlanta, USA, 2 Georgia Institute of Technology & Emory University, Atlanta, GA, USA. The most desirable approaches for characterization and manipulation within biological systems are optical-based. This is because of the non-invasive and high-resolution nature of optical techniques which has led to the widespread adoption of optical microscopy in biology. Therefore, the development of methods to harness light for delivering precise physical inputs to biological systems could potentially transform the study of mechanotransduction. To acheive this goal, we developed an approach for optically controlling receptor tension at the surface of living cells. This is achieved using optomechanical actuator nanoparticles that are controlled with non- invasive near-infrared light. Illumination leads to particle collapse within 1.2 msec, delivering ~13 pN piconewton forces to specific cell surface receptors with high spatial and temporal resolution. We specificaly decorate the surface of nanoactuators using the RGD peptide and immobilize the particles to conventional glass coverslips. Upon culturing of fibroblasts onto these surfaces, near-infrared illumination was used to exert pictonewton forces through the integrin receptors, thus mechanically controlling focal adhesion formation, cell protrusion, and cell migration in living cells. We demonstrate that 10-100 Hz frequency stimulation leads to paxillin and vinculin recruitment, as well actin polymerization in a Rho kinase independent manner. This material shows the first example of optically controlling cell migration without the use of genetic engineering.

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