Jay X. Tang Professor of Physics, Professor of Engineering

Professor Jay X Tang received his BS from Peking University, and PhD of Physics from Brandeis University. After postdoctoral training at Harvard Medical School, he served as assistant professor of physics at Indiana University from 1999-2002. Since 2003, he has been on the faculty at Brown University. He is currently Professor of Physics and Engineering.

Professor Tang's research area is experimental biophysics. His research focuses on cell mechanics and motility. The biological questions he attempts to address include morphology, pattern formation, force generation and motility of bacteria and other cells.

Professor Tang enjoys teaching of physics and biophysics. In his spare time, he enjoys playing with kids and playing card games such as bridge.

Brown Affiliations

Research Areas

scholarly work

1. Tang, J. and Fraden, S. Magnetic field induced isotropic-nematic phase transition in a colloidal suspension. Phys. Rev. Lett., 1993, 71, 3509-3512.

2. Tang, J. and Fraden, S. Isotropic-cholesteric phase equilibrium in colloidal suspensions of filamentous bacteriophage fd. Liquid Crystals, 1995, 19, 459-467.

3. Kas, J., Strey, H., Tang, J., Finger, D., Ezzell, R., Sackmann, E., and Janmey, P. F-actin, a model polymer for semiflexible chains in dilute, semidilute and liquid crystalline solutions. Biophysical Journal, 1996, 70, 609-625.

4. Tang, J., Wong, S., Tran, P, and Janmey, P., Cation induced bundle formation of rodlike polyelectrolytes, Ber. Bunsen-Ges.  Phys. Chem., 1996, 100, 796-806.

5. Tang, J. and Janmey, P. The polyelectrolyte nature of F-actin and the mechanism of actin bundle formation, J. of Biol. Chem., 1996, 271, 8556-8563.

6. Tang, J. and Fraden, S. None-monotonic temperature dependence of the flexibility of bacteriophage fd.  Biopolymers, 1996, 38, 13-22.

7. Tang, J. X., Szymanski, P., Janmey, P., and Tao, T. Electrostatic effects of smooth muscle calponin on actin assembly. Euro. J. Biochem., 1997, 247, 432-440.

8. Tang, J. X., Ito, T., Tao, T., Traub, P., and Janmey, P. Opposite effects of electrostatics and steric exclusion on bundle formation by F-actin and other filamentous polyelectrolytes. Biochemistry, 1997, 36, 12600-12607.

9. Kothakota, S., Azuma, T., Reinhard, C., Klippel, A., Tang, J. X., Chu, K., McGarry, T. J., Kirschner, M. W., Koths, K., Kwiatkowski, D., J., and Williams, L. T., Caspase-3-Generated Fragment of Gelsolin: Effector of Morphological Changes in Apoptosis, Science, 1997, 278, 294-298.

10. Parker, C. A., Takahashi, K. , Tang, J. X.,Tao, T., and Morgan, K. G., Cytoskeletal Targeting of Calponin in Differentiated, Contractile Smooth Muscle Cells, J. Physiology, 1998, 508.1, 187-198.

11. Guttenberg, Z., Tang, J. X., Isenberg, G., Ezzell, R. M., and Goldmann, W. H., Analysis of the F-actin binding fragments of vinculin using stopped-flow and dynamic light scattering measurements, Euro. J. Biochem., 1998, 254, 413-419.

12. Janmey, P., Kas, J., Shah, J. V., Allen, P. G., and Tang, J. X., Cytoskeletal networks and filament bundles: regulation by proteins and polycations, Biol. Bull., 1998, 194, 334-336.

13. Tang, J. X. and Janmey, P., Two distinct mechanisms of actin bundles formation, Biol. Bull., 1998, 194, 406-408.

14. Wriggers, W., Tang, J. X., Azuma, T., Marks, P., and Janmey, P. A., Cofilin and gelsolin segment 1: molecular dynamics simulation and biochemical analysis predict a similar actin binding mode, J. Mol. Biol., 1998, 282, 921-932.

15. Geng, Y., Azuma, T., Tang, J. X., Hartwig, J., Muszynski, M., Wu, Q., Libby, P., and Kwiatkowski, D.,  Caspase-3-induced gelsolin fragmentation contributes to actin cytoskeletal collapse, nucleolysis, and apoptosis of vascular smooth muscle cells exposed to proinflammatory cytokines, Euro. J. Cell Biol., 1998, 77 (December issue).

16. Lyubartsev, A., Tang, J. X., Janmey, P., and Nordenskiold, L., Electrostatically induced polyelectrolyte association of rodlike virus particles, Phys. Rev. Lett., 1998, 81, 5465-6468.

17. Xian, W., Tang, J. X., Janmey, P., Braunlin, W., A 25Mg NMR Study of Interaction between  F-actin and Mg2+, Biochemistry, 1999, 38, 7219-7226.

18. Tang, J. X. , Janmey, P., Stossel, T., and Ito, T., Thiol oxidation of actin produces dimers that enhance the elasticity of the F-actin network, Biophysical J.,  1999,  76, 2208-2215.

19. Leinweber, B., Tang, J. X., Stafford, W.F., and Chalovich, J. M., Calponin interaction with a-actinin-actin: Evidence for a structural role for calponin. Biophysical J., 1999, 77, 3208-3217.

20. Wong, G. C.-L., Tang, J. X., Lin, A., Li, Y., Janmey, P., and Safinya, C. R., Hierarchical self-assembly of F-actin and cationic lipid complexes: Stacked three-layer membranes forming giant ribbon-like tubules, Science, 2000, 288, 2035-2039.

21. Frank G. Schmidt, Hinner, B., Sackmann, E., and Tang, J. X., Viscoelastic properties of semiflexible filamentous bacteriophage fd, Phys. Rev. E, 2000, 62, 5509-5517.

22. Tang, J. X., Josef A. Käs, Jagesh V. Shah, and Paul A. Janmey, Counterion-induced actin ring formation. 2001, Euro. Biophys. J. 30, 477-484.

23. Tang, J. X., Janmey, P., Lyubartsev, A., and Nordenskiold, L., Metal Ion Induced Lateral Aggregation of Filamentous Viruses fd and M13. Biophys. J. 2002, 83, 566-581.

24. Viamontes, J., and Tang, J. X., A continuous isotropic-nematic liquid crystalline transition of F-actin solutions. Phys Rev E. 2003, 67, 040701.

25. Wong, G. C.-L., Lin, A., Tang, J. X., Li, Y., Janmey, P., and Safinya, C. R., Lamellar phase of stacked two-dimensional rafts of actin filaments. Phys. Rev. Lett., 2003, 91, 018103.

26. Butler, J. C., Angelini, T., Tang, J. X., and Wong, G. C.-L., Ion multivalence and like-charged polyelectrolyte attraction. Phys. Rev. Lett., 2003, 91, 028301.

27. Hosek, M., and Tang, J. X., Polymer-Induced Bundling of F-actin and the Depletion Force. Phys. Rev. E., 2004, 69, 051907.

28. Li, G., and Tang, J. X., Diffusion of actin filaments within a thin layer between two walls. Phys. Rev. E., 2004, 69, 061921.

29. Addas, K., Schmidt, C. F., and Tang, J. X., Microrheology of solutions of semiflexible biopolymer filaments using laser tweezers interferometry. Phys. Rev. E., 2004, 70, 021503.

30. Yang, L., Liang, H., Angelini, TE., Butler, J., Coridan, R., Tang, J. X., and Wong, G. C.-L., Self-assembled virus-membrane complexes. Nature Materials, 2004, 3, 615-619.

31. Wen, Q., and Tang, J. X., Absence of charge inversion for a system of charged rods and their divalent counterions. J. Chem. Phys., 2004, 121, 12666-12670.

32. Li, G., Smith, C. S., Brun, Y. V., and Tang, J. X., Elasticity of the Caulobacter crescentus adhesive holdfast. J. Bacteriology, 2005, 187, 257-265.

33. Li, G., Wen, Q., and Tang, J. X., Single filament electrophoresis of F-actin and filamentous virus fd. J. Chem. Phys., 2005, 122:104708.

34. Tang, J. X., Kang, H., and Jia, J., Intriguing self-assembly of large granules of F-actin facilitated by gelsolin and alpha-actinin. Langmuir, 2005, 21, 2789-2795.

35. Balter, A., and Tang, J. X., The hydrodynamic stability of helical growth at low Reynolds number, Phys. Rev. E., 2005, 71:051912.

36. Angelini, TE., Sanders, LK., Yang, L., Liang, H., Wriggers, W., Tang, J. X., and Wong, G. C.-L., Structure and dynamics of condensed multivalent ions within polyelectrolyte bundles: a combined X-ray diffraction and solid-state NMR study, J. Phys.: condensed matter, 2005, 17, S1123-S1135.

37. Tang, J. X., Qi Wen, Bennett, A., Kim, B., Bucki, R., and Janmey, P., Anionic poly(amino acid)s dissolve actin and DNA bundles, enhance DNAse activity, and reduce the viscosity of cystic fibrosis sputum, Am. J. Physiology, 2005, 289, L599-605.

38. Alipour-Assiabi, E., Li, G., Powers, T. R., and Tang, J. X., Fluctuation analysis of Caulobacter crescentus adhesion, Biophys. J., 2006, 90, 2206-2212.

39. Atakhorrami, M., Kwiecińska, J. I., Addas, KM, Koenderink, GH, Tang, J. X.,  Levine, AJ, MacKintosh, FC., and Schmidt, CF, Correlated fluctuations of microparticles in viscoelastic solutions: quantitative measurement of material properties by microrheology in the presence of optical traps. Phys Rev. E., 2006. 73, 061501.

40. Viamontes, J.,  Narayanan, S., Sandy, A. R., and Tang, J. X, The Orientational Order Parameter of the Nematic Liquid Crystalline Phase of F-actin. Phys Rev. E., 2006, 061901.

41. Tsang, P.,  Li, G., Brun, Y. V., Freund, L. B.,  and Tang, J. X., Adhesion of Single Bacterial Cells in the Micronewton Range. PNAS. 2006, 103, 5764-5768. Featured in Nature, Science News, National Public Radio, Fox News, etc.

42. Liu, Y., Guo, Y., Valles, J. M., and Tang, J. X., Microtubule Bundling and Nested Buckling Drive Stripe Formation in Polymerizing Tubulin Solutions. PNAS, 2006, 103, 10654-10659.

43. Li, G., and Tang, J. X., Low torque and high swimming efficiency of Caulobacter smarmer cells. Biophys. J., 2006, 91, 2726-2734.

44.  Wen, Q., and Tang, J. X., Temperature effects on the onset of aggregation of fd virus induced by divalent counterions. Phys. Rev. Lett., 2006, 97, 048101.

45. Viamontes, J., Patrick W. Oakes, and Tang, J. X., Isotropic to nematic liquid crystalline phase transition of F-actin varies from continuous to first order. Phys. Rev. Lett., 2006, 97, 118103.

46. Wen Q., Li, G., Tang, J. X., and Huber G., Switching statistics of a flagellar motor: first-passage time and dynamic binding, J. Statistical Physics, 2007, 128, 257-267.

47. Oakes, P., W., Viamontes, J., and Tang, J. X., Growth of tactoidal droplets during the first order isotropic to nematic phase transition of F-actin,  Phys Rev E., 2007, 75:061902.

48. Guo, Y., Liu, Y., Tang, J. X., and Valles, J. M., Polymerization force driven buckling of microtubule bundles determines the wavelength of patterns formed in tubulin solutions, Phys Rev Lett., 2007, 98:198103.

49. He, J., and Tang, J. X., Counter-ion Induced Abnormal Slowdown of F-actin Diffusion across Isotropic to Nematic Phase Transition, Phys. Rev. Lett., 2007, 99:068103.


50. Morin, N. A., Oakes, P. W., Hyun, Y-M, Lee, D., Chin, E. Y., King, M. R., Springer, T. A., Shimaoka, M., Tang, J. X., Reichner, J. S., Kim, M., Nonmuscle myosin heavy chain IIA mediates integrin LFA-1 de-adhesion  during T lymphocyte migration, J. Exp. Medicine, 2008, 205: 195-205.

51. He, J.,  Mak, M.,  Liu, Y.,  and Tang, J. X., Counterion Dependent Microrheological Properties of F-actin Solution across Isotropic-Nematic Phase Transition, 2008, Phys Rev E, 78:011908.

52. Guo, Y., Liu, Y., Tang, J. X., Oldenbourg, R., and Valles, J. M., Effects of osmotic force and torque on microtubule bundle and pattern formation, Phys Rev E., 2008, 78:041910.

53. Li, G.,  Tam, L.-K., and Tang, J. X. , Amplified effect of Brownian motion in bacterial near-surface swimming, PNAS, 2008, 105: 18355-18359.

54. Oakes, P. W.,  Patel, D., Morin, N. A., Zitterbart, D. P., Fabry, B., Reichner, J. S., and Tang, J. X. Neutrophil morphology and migration are affected by substrate elasticity, BLOOD, 2009, 114:1387-95.

55. Li, G., and Tang, J. X., Accumulation of microswimmers near a surface mediated by collisions and rotational Brownian Motion, Phys. Rev. Lett., 2009, 103:078101-104.

56. Kang, H., Carlsson, A. E., and Tang, J. X., A Kinetic overshoot in Actin network assembly induced jointly by branching and capping proteins, Phys. Rev. E, 2009, 80:041913.

57. S. Garg, J. X. Tang, J. Rühe, and C.A. Naumann, Actin-induced perturbation of PS lipid–cholesterol interaction: A possible mechanism of cytoskeleton-based regulation of membrane organization, Journal of Structural Biology, 2009, 168:11-20.

58. Kang, H., Q. Wen, P. A. Janmey, J. X. Tang, E. Conti and F. C. MacKintosh, Nonlinear Elasticity of Stiff Filament Networks: Strain Stiffening, Negative Normal Stress, and Filament Alignment in Fibrin Gels, J. Phys. Chem. B,  2009, 113, 3799–3805.

59. Kang, H., Wang, J. J., Longley, S. J., J. X. Tang, and S. K. Shaw, Relative actin nucleation promotion efficiency by WASP and WAVE proteins in endothelial cells, Biochem. & Biophys. Res. Comm., 2010, 400:661-666.

60. Kang, H., Perlmutter, D. S., Shenoy, V. B.,  and J. X. Tang, A kinematic description of deterministic actin trajectories induced by spherical beads, Biophys J., 2010, 99: 2793-2802 (Feature Article).

61. Ikuta, T.,  Thatte, H. S., Tang, J. X., Mukerji, I.,  Bridges, K. R., Knee, K., Wang, S. H., Montero-Huerta, P., Joshi, R. M., and Head, C. A.,  Nitric oxide reduces sickle hemoglobin polymerization: Potential role of nitric oxide-induced charge alteration in depolymerization, Archives of Biochemistry and Biophysics, 2011, doi:10.1016/j.abb.2011.03.013.

62. He J. and Tang, J. X., Effects of depletion and surface adsorption on microrheology of actin networks, Phys. Rev. E., 2011, 83:041902.

63. Faulds-Pain, A., Birchall, C., Aldridge, C., Smith, W. D., Grimaldi, G., Nakamura, S., Miyata, T., Gray, J., Li, G., Tang, J. X., Namba, K., Minamino, T., and Aldridge, P. D., Flagellin Redundancy in Caulobacter crescentus and Its Implications for Flagellar Filament Assembly, Journal of Bacteriology, 2011, 193:2695.

64. Li, G., Bensson, J., Nisimova, L., Munger, D., Mahautmr, P., Tang, J. X., Maxey, M. R., and Brun, Y. V., Accumulation of swimming bacteria near a solid surface, Phys. Rev. E., 2011, 84, 041932.

65. Li, G., Brown, P. J., Tang, J. X., Xu, J., Quardokus, E., M., Fuqua, C., and Brun, Y. V., Surface contact stimulates the just in time deployment of bacteria adhesions, Molecular Microbiology, 2012, 83: 41-51 (featured by a commentary article at the front of the issue).

66. Loosley, A. J., and Tang, J. X., Stick-slip motion and elastic coupling in crawling cells, Phys. Rev. E., 86, 031908, 2012.

67. Morse, M., Huang, A., Li, G., Maxey, M.R., and Tang, J. X., Molecular adsorption steers bacterial swimming at the air/water interface, Biophysical Journal, 2013, 105:21. doi: 10.1016/j.bpj.2013.05.026.

68. Li, G., Brun, Y. V., and Tang, J. X, Holdfast spreading and thickening during Caulobacter crescentus attachment to surfaces, BMC Microbiology, 2013, 13:139. doi: 10.1186/1471-2180-13-139.

69. Wang, J.J., Morabito, K., Tang, J. X., and Tripathi, A., Microfluidic platform for isolating nucleic acid targets using sequence specific hybridization, Biomicrofluidics, 2013, 7:044107, doi: 10.1063/1.4816943.

70. O'Brien, C., Loosley, A. J., Oakley, K., Tang, J. X., and Reichner, J., Introducing a Novel Metric, Directionality Time, to Quantify Human Neutrophil Chemotaxis as a Function of Matrix Composition and Stiffness, Journal of Leukocyte Biology, 2014, 95:1. doi:10.1189/jlb.0913478.

71. McMullen, A., de Haan, H. W., Tang, J. X., and Stein, D., Translocation of rodlike viruses through solid state nanopores, Nature Communications, 2014, 5:4171, doi: 10.1038/ncomms5171.

72. Liu, B., Gulino, M., Morse, M., Tang, J. X., Powers, T. R., and Breuer, K. S., Helical motion of the cell body enhances Caulobacter crescentus motility, 2014, PNAS, 111:11252-11256, doi:10.1073/pnas.1407636111.

73. Ping, L., Wu, Y., Hosu, B.G., Tang, J. X., and Berg, H. C., Osmotic pressure inside a bacterial swarm, Biophys. J, 2014, 107:871, doi:10.1016/j.bpj.2014.05.052.

74. Gao, Y., Neubauer, M., Yang, A., Johnson, N., Li, G., M. Morse, and Tang, J. X., Altered Motility of Caulobacter Crescentus in Viscous and Viscoelastic Media, 2014, Mio Med Central (BMC)  Microbiology,14:322. doi: 10.1186/s12866-014-0322-3.


75. Loosley, AJ, O’Brien, C, Reichner, J., and Tang, J. X., Describing Directional Cell Migration with a Characteristic Directionality Time, 2015, PLoS ONE, 10(5): e0127425. doi:10.1371/journal.pone.0127425.

research overview

Professor Tang's lab is currently involved in a new research program of molecular biophysics. The main research goal is to understand the mechanisms and properties of protein assemblies. In particular, the Tang lab studies the assembly of the so-called cytoskeletal proteins, such as actin and tubulin, which form long filaments. Higher levels of assembly occur in solutions of these filaments, including isotropic networks, liquid crystalline phases, and densely packed lateral aggregates. We seek to elucidate interactions that govern the formation of these states, predict and manipulate transitions among them, and explore biomedical applications.

research statement

Professor Tang is involved in a new research program of molecular biophysics. The main goal of his research effort is to understand the mechanisms and properties of protein assemblies. In particular, the Tang lab studies the assembly of the so-called cytoskeletal proteins, such as proteins called actin and tubulin, which form functional filaments in cells.

Filamentous assemblies of proteins and nucleotides form a class of biomaterials with physical properties distinct from those of most synthetic polymers. Among these biomaterials are cytoskeletal filaments including filamentous actin (F-actin), microtubules, and intermediate filaments; collagen fibers in the extra-cellular matrix; duplex DNA in both extended and condensed forms; and filamentous viruses such as the bacteriophages fd, M13, and pf1. Various states of assembly occur in solutions of this class of biopolymers, including isotropic networks, liquid crystalline phases, and densely packed lateral aggregates often described as paracrystalline bundles. Elucidating the molecular interactions that govern the formation of all these states will provide a means to predict and manipulate transitions among them, and will therefore have potential applications for material science and biomedical engineering.

The long-term goal of this line of research is to explore special features of these polymer systems in connection with phase transitions, and to identify and assess the inter-molecular forces that govern various states of assembly in aqueous solutions. We also explore strategies for potential treatment of certain human diseases based on the properties of large protein assemblies.

Additionally, the Tang laboratory has recently undertaken biophysical studies of bacterial adhesion and motility, using the aquatic bacterial species Caulobacter crescentus . The study has revealed extraordinary strength of adhesion, which has implications for potentially developing a new class of adhesives. An ongoing study of the Caulobacter swarmer cells suggests much higher swiming efficiency than E. coli and V. alginolyticus , showing an interersting example of adaptation of microorganisms through the course of evolution.

funded research

I. Current Grants

1. National Science Foundation, Division of Engineering  (CBET), Fluid Dynamics, Motion of Uni-flagellated Bacteria in Visco-elastic Media, $362,359, 09/01/2014-08/31/2017. PI:Tang, Co-PI: Pelcovits.

2. National Science Foundation, Physics of Living Systems (PLOS), entitled "Physics of near surface bacterial swimming", Sept, 2011-August, 2015, PI: Tang (300K).

3. Institute of Theoretical Physics, Chinese Academy of Sciences (CAS), entitled “Modeling bacterial motion in viscoelastic media”, June 2014-May 2016, PI: Tang (~40K); CAS collaborator: Ouyang, Zhongcan.


II. Completed Grants

1. Research Investment Fund (RIF) award from the Research and University Graduate School (RUGS), Indiana University, to purchase an atomic force microscope (AFM) for materials science and biological applications (co-PI with Dave Baxter), $150K, May, 2000.

2.  Indiana 21st Century Fund, entitled “Center for Membrane Protein Biotechnology”, 2002-2004, $1,320K. PI: Gil Lee, Purdue University. Tang’s portion as a Co-PI is $170K in two-year total. (Fund returned for leaving the state of Indiana).

3. Graduate Assistance in Areas of National Need (GAANN), Department of Education. $630K, August 2001-August 2004. This grant funds a departmental program of which Tang serves as a co-director. The grant provides full support for 7 graduate students each year to conduct research under the theme of microscopic physics and biophysics. (Participation ended due to departure from Indiana University).

4. National Science Foundation grant, entitled "Solution Physics of F-actin and Filamentous Bacteriophages", $270K, July, 2000-June 2003.

5. National Science Foundation Major Research Instrumentation (MRI) grant, entitled " Acquisition of a Scanning Probe Microscope for Studies of Biomolecules and Nanoscale Materials and Devices ", $133K, Sept, 2003-Aug 2004. PI: Tang. Co-PIs: Ling, Powers, Valles and Xiao.

6. Salomon Award, Brown University, research project entitled “Chemotactic trajectory and hydrodynamics of Caulobactor crescentus swarmer cells, June, 2004-May, 2005.

7. National Institute of Health R01 grant, entitled “Dissolution of polyelectrolyte bundles in airway fluids”, April, 2001-May 2006. PI: P.A. Janmey at U. Penn Medical School, with Tang as Subcontractor (Portion for Tang $350,000).

8.  NASA Ground Based Biology Study, entitled “Microscopic Studies of Gravi-Sensitive Microtubule Assembly in Simulated Variable Gravity Conditions, $472K, Jan, 2004-Dec, 2006. PI: Tang, Co-I: Valles.

9. National Science Foundation Award DMR 0405156, entitled "Compensatory Roles of Electrostatics and Depletion Force on the Aggregation of Filamentous Viruses and Protein Filaments", $273K, Aug, 2004-July 2007. PI: Tang.

10. Petroleum Research Fund, American Chemical Society, entitled “Liquid crystalline formation of filamentous actin assembly”, $80K, Sept, 2005-August, 2007. PI: Tang.

11. Brown Seed Fund, entitled “Integrin mediated adhesion and retraction during T cell migration”, PI: Tang, with L. Ben Freund, Minsoo Kim and Jonathan Reichner, $90,000, Feb 17, 2007-Feb 16, 2008.

12. National Institute of Health R21, entitled “Neutrophil Mechano-sensing”, July, 2008-June, 2010, PI: Reichner, Rhode Island Hospital, Subcontractor: Tang ($250 K).

13. National Institute of Health R01, entitled “Mechanism of Caulobacter Adhesion”, ~$1.1M, March 1, 2007-Feb 28, 2011. PI: Y. Brun, Indiana University. Subcontractor: Tang (~$400 K).

14. National Science Foundation, Directorate of Engineering (CMMI), entitled "Mechanics of intracellular pathogens and biomimetic systems propelled by actin comet tails", Sept, 2008-August, 2011.  PI: Vivek Shenoy, Co-PI: Tang ($350 K).

15. National Science Foundation, Directorate of Engineering (CMMI), entitled "Biomechanics of Actin Network Regulated by Physical Mechanisms", Sept, 2008-August, 2012.  PI:  Tang ($300 K).

16. Institute of Molecular and Nano Innovation (IMNI) Seed Award, Brown University, January 2011-June, 2012. PI: Tang, Co-PI: Stein ($40k).