Bulletin of the American Physical Society
Joint Fall 2011 Meeting of the Texas Sections of the APS, AAPT, and Zone 13 of the SPS
Volume 56, Number 7
Thursday–Saturday, October 6–8, 2011; Commerce, Texas
Session N7: Biological & Chemical Physics II |
Hide Abstracts |
Chair: Kelvin Chang, Texas Tech University Room: Science Building 123 |
Saturday, October 8, 2011 12:05PM - 12:17PM |
N7.00001: Adhesion Assay using Nano-Scaffolds for Metastatic Indicator James Matthews, Raul Martinez-Zanguilan, Soyeun Park It is important to determine the metastatic potential of prostate cancer cells because the metastasis seriously affects the survival of prostate cancer patients. Nevertheless, multi-faceted aspects of metastasis hinder its accurate evaluation. Considering the altered cell-to-substrate adhesion in cancer cells, we performed the adhesion assay using our state-of-art nanoscaffolds to determine the metastatic potential. We have used lowly (LnCap) and highly (CL-1) metastatic human prostate cancer cells. Using the nanosphere lithography, we created the nano-scaffolds with defined spacing and size of nano-islands in 2D array. Subsequent funtionalization using the orthogonal chemistry and selective absorption of extra-cellular matrix proteins allows us to control the adhesions. We found that while the cell proliferation of LnCaP is similar to that of normal cells, CL-1 shows the aggressive proliferation even with restricting the adhesions. We concluded that the high metastatic potential of CL-1 cells is attributed from the abnormally enhanced adhesions. [Preview Abstract] |
Saturday, October 8, 2011 12:17PM - 12:29PM |
N7.00002: Nano-Bio-Mechanics of Neuroblastoma Cells Using AFM Lyndon Bastatas, James Matthews, Min Kang, Soyeun Park We have conducted an \textit{in vitro} study to determine the elastic moduli of neurobalstoma cell lines using atomic force microscopy. Using a panel of cell lines established from neuroblastoma patients at different stages of disease progress and treatment, we have investigated the differences in elastic moduli during a course of cancer progression and chemotherapy. The cells were grown on the hard substrates that are chemically functionalized to enhance adhesion. We have performed the AFM indentation experiments with different applied forces from the AFM probe. For the purpose of the comparison between cell lines, the indentations were performed only on cell centers. The obtained force-distance curves were analyzed using the Hertz model in order to extract the elastic moduli. We have found that the elastic moduli of human neuroblastoma cells significantly varied during the disease progression. We postulate that the observed difference might be affected by the treatment and chemotherapy. [Preview Abstract] |
Saturday, October 8, 2011 12:29PM - 12:41PM |
N7.00003: Free energy profile of DNA from single-molecule manipulation experiments Eric Frey, Ching-Hwa Kiang Nonequilibrium work theorems, such as the Jarzynski equality and the Crooks fluctuation theorem, allow one to use nonequilibrium measurements to determine equilibrium free energies. For example, it has been demonstrated that the Crooks fluctuation theorem can be used to determine RNA folding energies. We used single-molecule manipulation with an atomic force microscope to measure the work done on poly(dA) as it was stretched and relaxed. This single-stranded nucleic acid exhibits unique base-stacking transitions in its force-extension curve due to the strong interactions among A bases, as well as multiple pathways. Here we showed that free energy curves can be determined by using the Crooks fluctuation theorem. The nonequilibrium work theorem can be used to determine free energy curves even when there are multiple pathways. [Preview Abstract] |
Saturday, October 8, 2011 12:41PM - 12:53PM |
N7.00004: In Vitro Microtubule and Motor Protein Motion on Glass A.L. Liao, A. Sikora, D. Oliveira, K. Kim, M. Umetsu, T. Adschiri, W. Hwang, W. Teizer The intracellular microtubule associated protein kinesin uses adenosine triphosphate (ATP) as an energy source for unidirectional and processive motion on a microtubule filament. In a cell, kinesin motor proteins function as transporters for organelles, macromolecules and various particles. To study the related processes \textit{in vitro}, we have performed rhodamine-labeled microtubule gliding assays and kinesin-coated quantum dot motility assays on glass surfaces. Motility is observed by fluorescence microscopy. Results from these two assays, as well as the effect of ATP concentration on kinesin velocity will be presented. We will discuss how we use these assays for the manipulation of microtubules on a surface, thus enabling specific particle distribution by kinesin. [Preview Abstract] |
Saturday, October 8, 2011 12:53PM - 1:05PM |
N7.00005: Atomistic MD simulations reveal the protective role of cholesterol in dimeric beta-amyloid induced disruptions in neuronal membrane mimics Liming Qiu, Creighton Buie, Sara Cheng, George Chou, Mark Vaughn, K. Cheng Interactions of oligomeric beta-amyloid peptides with neuronal membranes have been linked to the pathogenesis of Alzheimer's disease (AD). The molecular details of the interactions of different lipid components, particularly cholesterol (CHOL), of the membranes with the peptides are not clear. Using an atomistic MD simulations approach, the water permeability barrier, structural geometry and order parameters of binary phosphatidylcholine (PC) and PC/CHOL lipid bilayers were examined from various 200 ns-simulation replicates. Our results suggest that the longer length dimer (2 x 42 residues) perturbs the membrane more than the shorter one (2 x 40 residues). In addition, we discovered a significant protective role of cholesterol in protein-induced disruptions of the membranes. The use of a new Monte-Carlo method in characterizing the structures of the conformal annular lipids in close proximity with the proteins will be introduced. We propose that the neurotoxicity of beta-amyloid peptide may be associated with the nanodomain or raft-like structures of the neuronal membranes in-vivo in the development of AD. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700