? Protein deformation, protein folding, and protein interaction with other proteins (e.g., receptor-ligand binding) are all mediated by piconewton or femtonewton level forces. Only one of the existing low force application techniques can be used to impose forces of femtonewton level. Therefore, the overall goal of this proposal is to develop and validate a novel technique of imposing femtonewton level forces. The goal of the R21 phase of this proposal is to conduct a comprehensive numerical analysis and an experimental validation of the proposed technique (EMAT) to assess its feasibility.
The specific aims of the R21 phase are: 1) to conduct an axisymmetric analysis of the EMAT, 2) to conduct a three-dimensional analysis of the EMAT, and 3) to validate the EMAT with ultra-soft springs. The goal of the R33 phase of this proposal is to build a database that can be used by other researchers to calculate forces for various combinations of all the parameters involved, to build a device that can be used to further validate the EMAT experimentally, and to apply it to single receptor-ligand interactions.
The specific aims of the R33 Phase are: 1) to develop a computer program that can be used by others to easily calculate the force imposed with the EMAT, 2) to implement a computer-controlled micropipette manipulation system that can be used to impose femtonewton level forces, 3) to further validate the EMAT with optical tweezers, and 4) to examine the effect of force on the interaction between L-selectin and its ligands. The analyses proposed in the R21 phase will be performed with FIDAP (a finite element analysis software package for computational fluid dynamics) to evaluate the effects of some critical parameters and the alignment between the micropipette and transducer on the calculated force. The validation of the EMAT will be carried out with the micropipette manipulation system, ultra-soft springs, and optical tweezers. Combined with the micropipette aspiration technique, the EMAT will enable us to impose a wide range of forces from a few femtonewtons to about 100 nanonewtons, which is unprecedented. Therefore, the EMAT should have great potential to make an impact in the field of single molecule and single bond biophysics. ? ?

Agency
National Institute of Health (NIH)
Institute
National Center for Research Resources (NCRR)
Type
Exploratory/Developmental Grants (R21)
Project #
1R21RR017014-01A1
Application #
6598346
Study Section
Special Emphasis Panel (ZRR1-BT-1 (01))
Program Officer
Farber, Gregory K
Project Start
2003-05-01
Project End
2005-04-30
Budget Start
2003-05-01
Budget End
2004-04-30
Support Year
1
Fiscal Year
2003
Total Cost
$138,955
Indirect Cost
Name
Washington University
Department
Biomedical Engineering
Type
Schools of Engineering
DUNS #
068552207
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
Chen, Yong; Lu, Lan; Shao, Jin-Yu (2016) Endothelial Surface Protrusion by a Point Force. Biophys J 110:1150-7
Liu, Baoyu; Shao, Jin-Yu (2012) Tangential tether extraction and spontaneous tether retraction of human neutrophils. Biophys J 103:2257-64
Chen, Yong; Yao, Da-Kang; Shao, Jin-Yu (2010) The constitutive equation for membrane tether extraction. Ann Biomed Eng 38:3756-65
Ying, Junyi; Ling, Yingchen; Westfield, Lisa A et al. (2010) Unfolding the A2 domain of von Willebrand factor with the optical trap. Biophys J 98:1685-93
Chen, Yong; Liu, Baoyu; Xu, Gang et al. (2009) Validation, In-Depth Analysis, and Modification of the Micropipette Aspiration Technique. Cell Mol Bioeng 2:351-365
Liu, Baoyu; Yu, Yan; Yao, Da-Kang et al. (2009) A direct micropipette-based calibration method for atomic force microscope cantilevers. Rev Sci Instrum 80:065109
Xu, Gang; Shao, Jin-Yu (2008) Human neutrophil surface protrusion under a point load: location independence and viscoelasticity. Am J Physiol Cell Physiol 295:C1434-44
Liu, Baoyu; Goergen, Craig J; Shao, Jin-Yu (2007) Effect of temperature on tether extraction, surface protrusion, and cortical tension of human neutrophils. Biophys J 93:2923-33
Shao, Jin-Yu; Xu, Gang (2007) The adhesion between a microvillus-bearing cell and a ligand-coated substrate: a Monte Carlo study. Ann Biomed Eng 35:397-407
Yu, Yan; Shao, Jin-Yu (2007) Simultaneous tether extraction contributes to neutrophil rolling stabilization: a model study. Biophys J 92:418-29

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