Department of Physics & Astronomy
251A Clippinger Labs, Ohio University
Athens, OH45701
Office - 357A Clippinger Labs: (740) 593-1694
Lab - 367 & 355 Clippinger Labs: (740) 593-1725
Fax: (740) 593-0433
E-mail: tees@ohio.edu

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Current Research

Research interests

• Experimental determination of the response of single cell adhesion molecules to applied forces
• Computer simulations to determine receptor-ligand adhesive phenotype
• Understanding the mechanical properties of biological macromolecules
• Using cell adhesion molecule adhesive properties for sensors, biomimetic materials and drug targeting

Click here to download the Biophysics Poster for the Physics Open House, Nov 4-5, 2005

Active Projects

1. Cell adhesion in micropipettes as a model for capillary adhesion

Capillaries are the smallest blood vessels in ones body. They are smaller, in fact, than some of the cells that have to go through them. Red blood cells (which carry oxygen) are very deformable and go through easily. White blood cells are stiffer and take some time to deform before they can can fit in. Under normal circumstances, a large fraction of one's white cells are in the lung due to the large number of small vessels there. During infection, that fraction can go up even higher, leading to a disappearance of white cells from the rest of the body. Exactly how white cells become pooled in the lung and other capillary beds is not clear. Some say that it is due to "mechanical trapping", although the exact physical basis of this trapping is not clear. Another possibility is that adhesive proteins act as a kind of glue to trap cells. This second mechanism is known to work in larger vessels, but there don't seem to be a lot of these adhesive proteins in capillaries. Our work will examine these two possible mechanisms and clarify the factors that are required for mechanical trapping and adhesive trapping. We hypothesize that both factors are important under the right circumstances.

We use small glass tubes (micropipettes) with a diameter in the same range as capillaries as a model system. We have developed techniques for making micropipettes with different diameters and different rates of tapering. We can look at cells moving inside relatively straight tubes (like in the straight segments of capillaries) or in tapering regions (like at the entrances to capillaries). We coat the insides of the micropipettes with adhesive proteins to study the effects of adhesive proteins on cell motion inside the tubes. We can study ways to make the cells stick or not stick as desired.

The ability to control adhesion of white cells is important in the treatment of infection and cardiovascular diseases. The long-term goal is to understand what needs to be done in order to either promote (in the case of insufficient white cell arrest) or stop (in the case of too aggressive immune response) white cell adhesion in capillary beds. The technique developed here can thus be used as a research tool to assess whether new drugs will do what they need to do.

This work was initially supported by an award from the American Heart Association (AHA - Ohio Valley Affiliate). It is currently funded by a CAREER award (BES-0547165) from the National Science Foundation

2. Single molecule biophysics using force spectroscopy:

Receptor-ligand bonds are involved in fertilization, fetal development, blood vessel growth, blood clotting, cancer metastasis, inflammation, cell signaling and homeostatic physiology. Many receptor-ligand bonds, (especially those involved in cell adhesion) are designed to resist hydrodynamic or cytoskeletal applied forces. The behavior of bonds under applied load determines how cells will adhere in the circulation or migrate in tissue. The need to study the force dependence of bond reaction rates has led to the development of techniques (such as the microcantilever method) to apply picoNewton-level forces to single bonds.

• Measurement of the effect of mechanical forces on biological macromolecules
• Determination of how changes in structure caused by molecular deformation lead to changes in behavior at the cellular level.
• Effect of membrane protein clustering and on cell adhesion and signaling.
• Refinement of microcantilever technique to minimize non-specific binding and improve position and time resolution

Links to some useful materials about the cantilever system are given below. Some are rather large

For a PDF file of a tutorial on Single Molecule Forced Unbinding (given originally as a tutorial in March, 2004 at the American Physical Society meeting), click here.

Frames of an adhesive event between a bead and the tip of a microcantilever:

• Before event: the bead has given the cantilever a small negative displacement, forcing the surfaces together. Before Event
• Before event: the bead is being pulled by using a piezoelectric manipulator. The deflection of the cantilever is at a maximum. The bond breaks right after this frame. Max of Event
• Before event: the bond has broken, the bead is fully retracted and the cantilever has returned to its rest position. After Event

Video of a set of adhesive events between a bead coated with P-selectin and a microcantilever coated with P-selectin. The movie shows six touches. The first three show no adhesion, the fourth is a clear event, and the two touch that follows this show that there is no remaining bond. This rare one event out of eight touches implies that most touches result in no bonds, so the few events should be single bonds. video (46 Mbytes)

3. Biophysics of platelet adhesion:

Platelet adhesive interactions in flow are critical in hemostasis & thrombosis. Over the last 10 years, multistep paradigms have been proposed to explain how adhesion molecules cooperate to capture both leukocytes and platelets from flow to sites of need in hemostasis and atheroscolerosis. For leukocytes, selectins mediate a slow "rolling" type adhesion while beta2 integrins mediate firm capture once the molecules have been activated through chemokine signaling. Recently a similar process has been shown to operate for platelets. Von Willebrand Factor (binding to gpIb on the platelet) mediates slow platelet translocation while Fibrinogen (binding to the integrin alphaIIbbeta3) mediates the firm adhesion step. Platelets have also recently been shown to pull lipid bilayer tethers during translocation on von Willebrand Factor.

• Single molecule forced unbinding using a microcantilever device for von Willebrand Factor and Fibrinogen.
• Studies of platelet membrane tethering before, during and after platelet activation to study membrane-cytoskeletal interactions and platelet membrane mechanical properties.

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Techniques & Equipment

• Microcantilever Technique (custom built variant of AFM optimized for pN level force application)
• Fabrication of micropipettes
• Video Microscopy (Nikon TE300 inverted research microscope)
• Molecular biology wet lab
• Adsorption and covalent coupling of molecules to glass and latex surfaces
• Micromanipulation & Nanomanipulation
• Optical Tweezers (this is part of a Biophysics Lab Course that is under development.

Tees Lab Members

Current members:

Young Eun Choi - Ph.D. student

Steven Rogers - HTC Engineering Physics undergrad student

Alumni:

Prithu Sundd - Ph.D. November 2007. Dissertation: Micropipette Cell Adhesion Assay: A novel in vitro assay to modelleukocyte adhesion in the pulmonary capillaries of the lung. Currently at La Jolla Institute for Allergy and Infection.

Anand Pai - M.Eng. August 2006. Thesis: Micro-rheological Assessment of Neutrophil Mechanical Properties Following Adhesion in a Model Capillary. Currently Ph.D. student at Duke University.

Sulaiman Kareem, MS (2004-2007). Worked on single molecule forced unbinding of adhesive glycoproteins from the plant cell wall.

Vasile-Iulian Clapa, MS (2004-2005): Development of quadrant photodiode systems (Now at Wesleyan University, CT).

Tariq Ali, MS (2003-2004): Developed pulled optical fiber microcantilever systems for single molecule biophysics research. (Now at SUNY Buffalo, NY)

Joel Smith - Summer undergrad student 2006

Nicholas Malisse - Summer undergrad student 2003

Jessica Benson - Summer undergrad student 2002

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Recruiting

I am recruiting for a graduate student (Spring 2008) and I am always interested in discussing summer projects with undergraduate students [I have ate least one and maybe two slots for undergrads].

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Links

The following links should provide useful background information including why we want to study the biophysics of adhesion molecules (e.g. that it will ultimately help with diagnosis and treatment of disease). Feel free to suggest good new links. It is also very helpful to look for papers that cite these papers in ISI:

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How to get up to speed for graduate studies in the Tees lab:

I suggest downloading and reading the following references for background information, and then following up on the papers they reference. If you can't download these papers, see me and I'll lend you copies. It is also necessary to start following the literature. Perusing Biophysical Journal (which comes out once a month) and Proceedings of the National Academy of Sciences U.S.A. and Langmuir (which come out every two weeks) is a good start. If you have no previous biophysics training consider taking my course PHYS 461/561: Cell and Molecular Biophysics. Another way to learn the necessary background is to get a copy of Alberts et al.'s Molecular Biology of the Cell and start reading at Chapter 1. The first chapter of D. A. Lauffenburger's Receptors book (the link has some sample pages from Chpater 1) is also an excellent introduction to the physical chemistry of cell adhesion. I recommend getting a medical dictionary as well (Dorland's is good). Look at the tutorial (4 MB) on Single Molecule Forced Unbinding that I gave at the Americal Physical Society's meeting in March, 2004.

My Papers:

Pai, A., Sundd, P. and Tees, D.F.J. In situ microrheological determination of neutrophil stiffening following adhesion in a model capillary. Annals of Biomedical Engineering, 36(4):596-603. DOI: 10.1007/s10439-008-9437-8. (Abstract) (PDF)

Sundd, P., X. Zou, D.J. Goetz, and D.F.J. Tees. Leukocyte adhesion in capillary-sized, P-selectin-coated micropipettes. Microcirculation, 15(2):109-122, 2008 (Published online Nov. 2007). DOI: 10.1080/10739680701412971. (Abstract) (PDF)

Tees, D.F.J. and D.J. Goetz. Leukocyte adhesion: An exquisite balance of hydrodynamic and molecular forces. News in Physiological Sciences, 18:186-190, 2003. (Abstract) (PDF)

Tees, D.F.J., K.-C. Chang, S. D. Rodgers, and D. A. Hammer. Simulation of cell adhesion to bioreactive surfaces in shear: the effect of cell size. Industrial and Engineering Chemistry Research 41:486-493, 2002. (Abstract) (PDF)

Tees, D.F.J., J.T. Woodward, and D.A. Hammer. Reliability theory for receptor-ligand bond dissociation. Journal of Chemical Physics, 114:7477-7482, May 1, 2001. (Full Text) (PDF)

Tees, D.F.J., R.E. Waugh, and D.A. Hammer. A microcantilever device to assess the effect of force on the lifetime of selectin-carbohydrate bonds. Biophysical Journal, 80:668-682, February 2001. (Abstract) (PDF)

Chang, K.-C., Tees, D.F.J., and D.A. Hammer. The state diagram for cell adhesion under flow: leukocyte rolling and firm adhesion. Proceedings of the National Academy of Sciences U.S.A., 97:11262-11267, 2000. (Abstract) (PDF) Paper received an "Editor's Choice" notice in Science, 290:235, 2000

Long, M., H.L. Goldsmith, D.F.J. Tees, and C. Zhu. Probabilistic modeling of shear-induced formation and breakage of doublets cross-linked by receptor-ligand bonds. Biophysical Journal, 76:1112-1128, 1999. (Abstract) (PDF)

Tees, D.F.J., and H.L. Goldsmith. Kinetics and locus of failure of receptor-ligand mediated adhesion between latex spheres. I. Protein-carbohydrate bond. Biophysical Journal, 71:1102-1114, 1996. (Abstract) (PDF)

Kwong, D., D.F.J. Tees, and H.L. Goldsmith. Kinetics and locus of failure of receptor-ligand mediated adhesion between latex spheres. II. Protein-protein bond. Biophysical Journal, 71:1115-1122, 1996. (Abstract) (PDF)

Tees, D.F.J., O. Coenen and H.L. Goldsmith. Interaction forces between red cells agglutinated by antibody. IV. Time and force dependence of break-up. Biophysical Journal 65:1318-1334, 1993. (Abstract) (PDF)

Biophysics of Cell Adhesion:

Look at the tutorial (4 MB) on Single Molecule Forced Unbinding that I gave at the Americal Physical Society's meeting in March, 2004.

Bell, G. I. 1978. Models for the specific adhesion of cells to cells. Science (Washington D.C.). 200:618-627. (PDF)

Dembo, M., D. C. Torney, K. Saxman, and D. Hammer. 1988. The reaction limited kinetics of membrane-to-surface adhesion and detachment. Proceedings of the Royal Society of London. B. Biological Sciences. 234:55-83. (PDF)

Evans, E., D. Berk, and A. Leung. 1991. Detachment of agglutinin-bonded red blood cells I. Forces to rupture molecular-point attachments. Biophysical Journal. 59:838-848. (PDF)

Force Spectroscopy:

Evans, E. 1999. Energy landscapes of biomolecular adhesion and receptor anchoring at interfaces explored with dynamic force spectroscopy. Faraday Discussions. 111:1-16. (PDF)

Evans, E. 2001. Probing the relation between force-lifetime-and chemistry in single molecular bonds. Annual Review of Biophysics and Biomolecular Structure. 30:105-128. (PDF)

Evans, E., and K. Ritchie. 1997. Dynamic strength of molecular adhesion bonds. Biophysical Journal. 72:1541-1555. (PDF)

Merkel, R. 2001. Force spectroscopy on single passive biomolecules and single biomolecular bonds. Physics Reports. 346:343-385. (PDF)

Merkel, R., P. Nassoy, A. Leung, K. Ritchie, and E. Evans. 1999. Energy landscapes of receptor-ligand bonds explored with dynamic force spectroscopy. Nature. 397:50-53. (PDF)

Seifert, U. 2000. Rupture of multiple parallel molecular bonds under dynamic loading. Physical Review Letters. 84:2750-2753. (PDF)

White blood cell adhesion:

Alon, R., S. Chen, R. Fuhlbrigge, K. D. Puri, and T. A. Springer. 1998. The kinetics and shear threshold of transient and rolling interactions of L-selectin with its ligand on leukocytes. Proceedings of the National Academy of Sciences U.S.A. 95:11631-11636. (PDF)

Alon, R., D. A. Hammer, and T. A. Springer. 1995. Lifetime of the P-selectin-carbohydrate bond and its response to tensile force in hydrodynamic flow. Nature. 374:539-542. (PDF)

Brunk, D. K., and D. A. Hammer. 1997. Quantifying rolling adhesion with a cell-free assay: E-selectin and its carbohydrate ligands. Biophysical Journal. 72:2820-2833. (PDF)

Chang, K.-C., and D. A. Hammer. 2000. Adhesive dynamics simulations of sialyl-Lewisx/E-selectin-mediated rolling in a cell-free system. Biophysical Journal. 79:1891-1902. (PDF)

Chen, S., and T. A. Springer. 2001. Selectin receptor-ligand bonds: formation limited by shear rate and dissociation governed by the Bell model. Proceedings of the National Academy of Sciences U.S.A. 98:950-955. (PDF)

Lawrence, M. B., and T. A. Springer. 1991. Leukocytes roll on a selectin at physiological flow rates: distinction from and prerequisite for adhesion through integrins. Cell. 65:859-874. (PDF)

Lawrence, M. B., and T. A. Springer. 1993. Neutrophils roll on E-selectin. Journal of Immunology. 151:6338-6346. (PDF)

Springer, T. A. 1990. Adhesion receptors of the immune system. Nature. 346:425-434. (PDF)

Springer, T. A. 1994. Traffic signals for lymphocyte recirculation and leukocyte emigration: the multistep paradigm. Cell. 76:301-314. (PDF)

Adhesion in Capillaries

Andonegui G, Bonder CS, Green F, Mullaly SC, Zbytnuik L, Raharjo E, Kubes P. 2003. Endothelium-derived toll-like receptor-4 is the key molecule in LPS-induced neutrophil sequestration into lungs. Journal of Clinical Investigation 111(7):1011-1020. (PDF)

Bathe M, Shirai A, Doerschuk CM, Kamm RD. 2002. Neutrophil transit times through pulmonary capillaries: the effects of capillary geometry and fMLP-stimulation. Biophysical Journal 83(4):1917-1933. (PDF)

Burns AR, Smith CW, Walker DC. 2003. Unique structural features that influence neutrophil emigration into the lung. Physiological Reviews 83(2):309-336. (PDF)

Doerschuk CM. 2001. Mechanisms of leukocyte sequestration in inflamed lungs. Microcirculation 8(2):71-88. (PDF)

Doerschuk CM, Beyers N, Coxson HO, Wiggs B, Hogg JC. 1993. Comparison of neutrophil and capillary diameters and their relation to neutrophil sequestration in the lung. Journal of Applied Physiology 74(6):3040-3045. (PDF)

Erzurum SC, Downey GP, Doherty DE, Schwab III B, Elson EL, Worthen GS. 1992. Mechanisms of lipopolysaccharide-induced neutrophil retention: relative contributions of adhesive and cellular mechanical properties. Journal of Immunology 149(1):154-162. (PDF)

Evans E, Rawicz W. 1990. Entropy-driven tension and bending elasticity in condensed-fluid membranes. Physical Review Letters 64(17):2094-2097. (PDF)

Gebb SA, Graham JA, Hanger CC, Godbey PS, Capen RL, Doerschuk CM, Wagner Jr WW. 1995. Sites of leukocyte sequestration in the pulmonary microcirculation. Journal of Applied Physiology 79(2):493-497. (PDF)

Guntheroth WG, Luchtel DL, Kawabori I. 1982. Pulmonary microcirculation: Tubules rather than sheet and post. Journal of Applied Physiology 53(2):510-515. (PDF)

Kubo H, Doyle NA, Graham L, Bhagwan SD, Quinlan WM, Doerschuk CM. 1999. L- and P-selectin and CD11/CD18 in intracapillary neutrophil sequestration in rabbit lungs. American Journal of Respiratory and Critical Care Medicine 159(1):267-274. (PDF)

Kuebler WM, Kuhnle GEH, Groh J, Goetz AE. 1997. Contribution of selectins to leucocyte sequestration in pulmonary microvessels by intravital microscopy in rabbits. Journal of Physiology-London 501(2):375-386. (PDF)

Shao JY, Hochmuth RM. 1997. The resistance to flow of individual human neutrophils in glass capillary tubes with diameters between 4.65 and 7.75 mm. Microcirculation 4(1):61-74. (PDF)

Yeung A, Evans E. 1989. Cortical shell-liquid core model for passive flow of liquid-like spherical cells into micropipets. Biophysical Journal 56:139-149. (PDF)

Platelet adhesion:

Ruggeri, Z. M. 1993. von Willebrand factor and fibrinogen. Current Opinion in Cell Biology. 5:898-906. (PDF)

Ruggeri, Z. M., J. A. Dent, and E. Saldívar. 1999. Contribution of distinct adhesive interactions to platelet aggregation in flowing blood. Blood. 94:172-178. (PDF)

Savage, B., E. Saldívar, and Z. M. Ruggeri. 1996. Initiation of platelet adhesion by arrest onto fibrinogen or translocation on von Willebrand factor. Cell. 84:289-297. (PDF)

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