Chemical & Biomolecular Engineering

Top 20 Doctoral Program—National Research Council

Location

Dept. of Chemical & Biomolecular Engineering
University of Houston
S222 Engineering Bldg 1,
Houston, TX 77204-4004
phone: 713-743-4300

Faculty

Dr. Jacinta C. Conrad

Assistant Professor of Chemical and Biomolecular Engineering

Office Location: S226, Engineering Building 1

Tel: (713) 743-3829 | Fax: (713) 743-4323

Email: jcconrad [at] uh [dot] edu

Website: http://conradlab.chee.uh.edu

Education

  • S.B. Mathematics, University of Chicago (1999)
  • M.A. Physics, Harvard University (2002)
  • Ph.D. Physics, Harvard University (2005)
  • Postdoctoral Research Associate, University of Illinois (2005–2009)

Courses

  • Spring 2013: CHEE 3363, Fluid Mechanics for Chemical Engineers.
  • Fall 2012: CHEE 6333, Transport Processes.
  • Fall 2012: CHEE 6327, Experimental Methods in Chemical Engineering (lecturer).
  • Spring 2012: CHEE 3363, Fluid Mechanics for Chemical Engineers.
  • Fall 2011: CHEE 6333, Transport Processes.
  • Fall 2011: CHEE 6327, Experimental Methods in Chemical Engineering (lecturer).
  • Spring 2011: CHEE 3363, Fluid Mechanics for Chemical Engineers.
  • Fall 2010: CHEE 6327, Experimental Methods in Chemical Engineering (lecturer).
  • Spring 2010: CHEE 3363, Fluid Mechanics for Chemical Engineers.

Research Interests

We are broadly interested in the interaction between complex fluids (polymers, colloids, nanoparticles, bacteria, protozoa, cells) and the surfaces that confine or support them. These interactions appear ubiquitously in applications in petroleum engineering (drilling media, microbial corrosion), environmental engineering (biofouling, bioremediation), materials engineering (rapid prototyping, direct-write assembly), and biodefense (diagnostics, biodetection).  Moreover, this broad class of problems is scientifically fascinating: both the chemical and mechanical properties of surfaces can influence the adhesion, diffusion, motility, and phase behavior of complex fluids. Our current research thrusts include:

Flow and Transport of Complex Fluids in Confinement

Processes involving the flow of complex fluids in confined geometries appear prominently in technological, environmental, and physiological settings. Confinement effects strongly influence multiphase transport properties, and are thus relevant for technological applications involving porous media, such as gel electrophoresis and chromatography, and critical resource applications, such as water remediation and oil extraction from nonconventional sources. Despite their ubiquity, the science underlying these processes remains poorly understood. We use confocal and light microscopy to directly image the flow of complex fluids in microchannels. By quantifying the flow behavior in a variety of controlled microscale geometries using high-throughput tracking algorithms, we will elucidate the effects of confinement on the flow properties of complex fluids and inspire new designs for manipulating these materials on the microscale. Currently, we are investigating the effects of confinement on the structure, dynamics, and phase behavior of quiescent and flowing model colloid-polymer mixtures, and the transport properties of nanoparticles in microfabricated post arrays and polymer solutions.

Near-Surface Motility of Microorganisms

Over 99% of bacteria live in bacterial biofilms, which are surface-associated communities surrounded by a protective extracellular matrix that increases the resistance of bacteria to environmental and host stresses.  These stress-resistant biofilms thus cause significant problems both in human health and in industrial processes.  Preventing their formation requires understanding how bacteria adapt their motility mechanisms near surfaces.  We  directly image the motion of bacteria and other microorganisms near engineered surfaces with confocal and light microscopy.  By translating microscopy images into a searchable database of trajectories, we will elucidate the effects of surface properties on microbial motility and inspire new strategies to create antifouling materials.  Currently, we are quantifying the near-surface motility mechanisms of model bacteria on engineered surfaces.

Porous Particles and Scaffolds

 

The recent explosion in two- and three-dimensional microfabrication techniques has enabled the fabrication of novel materials with controlled nano- and microscale structure. However, to produce materials with additional functionality, further control over the microstructure is required. In particular, particles and scaffolds with controlled porosity have important practical applications as materials for separations, drug delivery, tissue engineering, cell culture, and catalysis. Moreover, these materials enable new investigations of flow and transport in controlled model systems. Currently, we are investigating the relationship between microstructure and porosity in phase-separating copolymer blends to be used as feedstocks for microfluidic emulsification.

 

Research Group

  • Graduate students: Firoozeh Babaye Khorasani, Jinsu Kim, Rahul Pandey, Sumedha Sharma, Vivek Yadav
  • Undergraduate students: Corey Knutson

Awards and Honors

  • 2012 NSF CAREER
  • 2010 University of Houston New Faculty Award
  • 2005–2007 INEST Postdoctoral Fellowship
  • 1999–2002 NSF Graduate Fellowship

Professional Activities

  • Reviewer for European Journal of Physics E, Langmuir, Journal of Rheology, PNAS, RSC Advances, Soft Matter, the National Science Foundation, and the ACS Petroleum Research Fund.
  • Member of the American Physical Society, American Chemical Society, American Institute of Chemical Engineers, and the Society of Rheology.

Journal Papers / Refereed Journal Publications

  1. S. P. George, H. Chen, J. C. Conrad, and S. Khurana,

    “Regulation of directional cell migration by membrane-induced actin bundling.” J. Cell. Sci. 126, 312–326 [DOI]

    , 2013
  2. J. C. Conrad,

    “Quantifying collective behavior in mammalian cells.” Proc. Natl. Acad. Sci. USA 109, 7591–7592. [DOI]

    , 2012
  3. J. C. Conrad,

    “Physics of bacterial near-surface motility using flagella and type IV pili: implications for biofilm formation.” Res. Microbiol. 163, 619–629 [DOI]

    , 2012
  4. K. He, M. Spannuth, J. C. Conrad, and R. Krishnamoorti,

    “Diffusive dynamics of nanoparticles in aqueous dispersions.” Soft Matter 8, 11933–11938. [DOI]

    , 2012
  5. M. Spannuth and J. C. Conrad,

    “Confinement-induced solidification of colloid-polymer depletion mixtures.” Phys. Rev. Lett. 109, 028301. [DOI]

    , 2012
  6. R. F. Shepherd, J. C. Conrad, T. Sabuwala, G. G. Gioia, and J. A. Lewis,

    “Structural evolution of cuboidal granular media.” Soft Matter 8, 4795–4801. [DOI]

    , 2012
  7. R. Pandey and J. C. Conrad,

    “Effects of attraction strength on microchannel flow of colloid-polymer depletion mixtures.” Soft Matter 8, 10695-10703 [DOI]

    , 2012
  8. F. Jin*, J. C. Conrad*, M. L. Gibiansky, and G. C. L. Wong (*Equal contribution),

    “Bacteria use type-IV pili to slingshot on surfaces.” Proc. Natl. Acad. Sci. USA 108, 12617–12622. [DOI]

    , 2011
  9. J. C. Conrad*, M. L. Gibiansky*, F. Jin, V. D. Gordon, D. A. Motto, M. A. Mathewson, W. G. Stopka, D. C. Zelasko, J. D. Shrout, and G. C. L. Wong (*Equal contribution),

    “Flagella and pili-mediated near-surface single-cell motility mechanisms in P. aeruginosa.” Biophys. J. 100, 1608–1616. [DOI]

    , 2011
  10. J. C. Conrad, S. R. Ferreira, J. Yoshikawa, R. F. Shepherd, B. Y. Ahn, and J. A. Lewis,

    “Designing colloidal suspensions for directed materials assembly.” Curr. Opin. Colloid Interface Sci., 16, 71–79. [DOI]

    , 2011
  11. J. C. Conrad and J. A. Lewis,

    “Structural evolution of colloidal gels during constricted microchannel flow.” Langmuir 26, 6102–6107. [DOI]

    , 2010
  12. J. C. Conrad, H. M. Wyss, S. Manley, V. Trappe, K. Miyazaki, L. J. Kaufman, A. B. Schofield, D. R. Reichman, and D. A. Weitz,

    “Arrested fluid-fluid phase separation in depletion systems: implications of the characteristic length on gel formation and rheology.” J. Rheol., 54, 412–438. [DOI]

    , 2010
  13. M. L. Gibiansky*, J. C. Conrad*, F. Jin, V. D. Gordon, D. A. Motto, M. A. Mathewson, W. G. Stopka, D. C. Zelasko, J. D. Shrout, and G. C. L. Wong (*Equal contribution),

    “Bacteria use type IV pili to walk upright and detach from surfaces.” Science 330, 197. [DOI]

    , 2010
  14. D. J. Harris, J. C. Conrad, and J. A. Lewis,

    “Evaporative lithographic patterning of binary colloidal films.” Phil. Trans. R. Soc. A. 367, 5157–5165. [DOI]

    , 2009
  15. J.C. Conrad and J.A. Lewis,

    “Structure of colloidal gels in microchannels.” Langmuir 24, 7628–7635. [DOI]

    , 2008
  16. D.J. Harris, H. Hu, J.C. Conrad, and J.A. Lewis,

    “Patterning colloidal films via evaporative lithography.” Phys. Rev. Lett. 98, 148301. [DOI]

    , 2007
  17. J.C. Conrad, P.P. Dhillon, E.R. Weeks, D.R. Reichman, and D.A. Weitz,

    “Slowly evolving caged clusters in supercooled fluids and glasses contribute to bulk elasticity.” Phys. Rev. Lett. 97, 265701. [DOI]

    , 2006
  18. P.J. Lu, J.C. Conrad, H.M. Wyss, A.B. Schofield, and D.A. Weitz,

    “Fluid of clusters in attractive colloids.” Phys. Rev. Lett. 96, 028306. [DOI]

    , 2006
  19. R.F. Shepherd, J.C. Conrad, S.K. Rhodes, D.R. Link, M. Marquez, D.A. Weitz, and J.A. Lewis,

    “Microfluidic assembly of homogeneous and Janus colloid-filled hydrogel granules.” Langmuir 22, 8618–8622. [DOI]

    , 2006
  20. J.C. Conrad, F.W. Starr, and D.A. Weitz,

    “Weak correlations between local density and dynamics in liquids near the glass transition.” J. Phys. Chem. B 109, 21235–21240. [DOI]

    , 2005
  21. S. Manley, H.M. Wyss, K. Miyazaki, J.C. Conrad, V. Trappe, L.J. Kaufman, D. R. Reichman, and D. A. Weitz,

    “Dynamic arrest in spinodal decomposition as a route to gelation.” Phys. Rev. Lett. 95, 238302. [DOI]

    , 2005

Conference Proceedings Publications

  1. M. Spannuth and J. C. Conrad,

    “Dynamics of confined colloid-polymer mixtures.” AIP Conf. Proc. 1518, 351–356 [DOI]

    , 2013