Dynamics of Weakly Aggregated Colloidal Particles (2008)
Maria L. Kilfoil, Eugene E. Pashkovski, James A. Masters, D. A. Weitz
We discuss the behavior of the dynamics of colloidal particles with a weak attractive interparticle interaction that is induced through the addition of polymer to the solvent. We briefly review the...
Manuscript information: Text: 20 pages (2008)
J. Liu, K. E. Kasza, G. H. Koenderink, D. Vader, C. P. Broedersz, D. A. Weitz
Abstract: Cross-linked actin networks are remarkable materials with unusual mechanical properties. Their elasticity is typically highly nonlinear, exhibiting a striking increase in stiffness with...
Velocity Fluctuations in a Fluidized Bed (2008)
Shang-you Tee, P. J. Mucha, M. P. Brenner, D. A. Weitz
We investigate the velocity fluctuations of particles in fluidized beds at low Reynolds number. Even in steady state, the average particle concentration, velocity fluctuations and correlation length...
IOP PUBLISHING JOURNAL OF PHYSICS: CONDENSED MATTER (2008)
J. Phys, Condens Matter, Eric R Weeks, John C Crocker, D A Weitz
Short- and long-range correlated motion observed in
www.elsevier.com/locate/ces (2008)
F. Sarrazin, L. Prat, N. Di Miceli, G. Cristobal, L. Prat, ...
Mixing characterization inside micro-droplets engineered on a microcoalescer, Chemical Engineering Science, doi:10.1016/j.ces.2006.10.013 This is a PDF file of an unedited manuscript that has been...
Particle-Stabilized Defect Gel in Cholesteric Liquid Crystals (2008)
Martin Zapotocky, Laurence Ramos, T. C. Lubensky, D. A. Weitz
Dispersions of colloidal particles in cholesteric liquid crystals form an unusual solid by stabilizing a network of linear defects under tension in the ideal layered structure of the cholesteric. The...
Positively Charged Vesicles and Negatively Charged Objects (2008)
V. Balzani, M. Gomez-lopez, J. F. Stoddart, A. Credi, V. Balzani, S. J. Langford, ...
Å 2 /molecule for R(2). Previous work on LB films of
Dripping, Jetting, Drops, and Wetting: The Magic of (2008)
A. S. Utada, A. Fern, D. R. Link, C. Holtze, D. A. Weitz
The following article is based on the Symposium X presentation given by David A. Weitz (Harvard University) on April 11, 2007, at the Materials Research Society Spring Meeting in San Francisco. The...
Patterned colloidal coating using adhesive emulsions (2007)
We present a novel approach to colloidal coating that exploits the adhesion properties of emulsion droplets. We use a patterned substrate consisting of hydrophobic patches on an otherwise hydrophilic...
From Colloidal Aggregation to Spinodal Decomposition in Sticky Emulsions (2007)
Poulin Bibette Andd, P. Poulin, J. Bibette, D. A. Weitz
. Aggregation mechanisms of emulsions at high initial volume fractions (#0 > 0.01) is studied using light scattering. We use emulsion droplets which can be made unstable towards aggregation by a...
Velocity Fluctuations in Fluidized Suspensions Probed By Ultrasonic Correlation Spectroscopy. (2007)
Cowan Page And, M. L. Cowan, D. A. Weitz
: Velocity fluctuations in a fluidized suspension of particles are investigated using two new ultrasonic correlation spectroscopies: Diffusing Acoustic Wave Spectroscopy (DAWS) and Dynamic Sound...
Particle-Stabilized Defect Gel in Cholesteric Liquid Crystals (2007)
Martin Zapotocky, Laurence Ramos, T. C. Lubensky, D. A. Weitz
Dispersions of colloidal particles in cholesteric liquid crystals form an unusual solid by stabilizing a network of linear defects under tension in the ideal layered structure of the cholesteric. The...
Microscope-based static light scattering apparatus (2007)
M. T. Valentine, P. D. Kaplan, D. A. Weitz
We describe a new design for a microscope-based static light scattering instrument that provides simultaneous high-resolution images and static light scattering data. By correlating real space images...
T. Gisler, K. Kroy, E. Frey, D. A. Weitz
We report measurements of the frequency-dependent complex shear modulus of semidilute F-actin solutions based on optical observations of the thermally excited motion of monodisperse tracer...
Rheology of defect networks in cholesteric liquid crystals (2007)
Laurence Ramos, Martin Zapotocky Y, T. C. Lubensky, D. A. Weitz
The rheological properties of cholesteric liquid crystals containing networks of defects are investigated. A network of linear defects of the \oily-streak " type is stabilized when colloidal...
Mason et al. Vol. 14, No. 1/January 1997/J. Opt. Soc. Am. A 139 Diffusing-wave-spectroscopy measurements
Microscope-based static light-scattering instrument (2007)
M. T. Valentine, D. A. Weitz, P. D. Kaplan
We describe a new design for a microscope-based static light-scattering instrument that provides simultaneous high-resolution images and static light-scattering data. By correlating real space images...
Three-Dimensional Confocal Microscopy of Colloids (2007)
Dinsmore Eric Weeks, A. D. Dinsmore, Eric R. Weeks, Vikram Prasad, Andrew C. Levitt, D. A. Weitz
this paper, we focus on colloidal gels, colloidal glasses, and binary colloidal fluids. In each of these cases, we show how these measurements provide qualitatively new understanding of colloidal...
Measuring the Mechanical Stress Induced by an Expanding (2007)
Multicellular Tumor System, V. D. Gordon, M. T. Valentine, M. L. Gardel, D. Andor-ardó, S. Dennison, ...
Rapid volumetric growth and extensive invasion into brain parenchyma are hallmarks of malignant neuroepithelial tumors in vivo. Little is known, however, about the mechanical impact of the growing...
Europhys. Lett., 58 (5), pp. 679--685 (2002) (2007)
Europhysics Letters June, P. Mach, P. Wiltzius, M. Megens, D. A. Weitz, Keng-hui Lin, ...
We have incorporated nematic liquid crystal into periodic, polymer host structures templated from self-assembled colloids. Using these composite materials, we demonstrate the first electrically...
Non-equilibrium microtubule fluctuations in a model cytoskeleton (2007)
Brangwynne, C. P., Koenderink, G. H., MacKintosh, F. C., Weitz, D. A.
Biological activity gives rise to non-equilibrium fluctuations in the cytoplasm of cells; however, there are few methods to directly measure these fluctuations. Using a reconstituted actin...
Liu, J., Koenderink, G. H., Kasza, K. E., MacKintosh, F. C., Weitz, D. A.
We image semi-flexible polymer networks under shear at the micrometer scale. By tracking embedded probe particles, we determine the local strain field, and directly measure its uniformity, or degree...
Rheology and microrheology of a microstructured fluid: The gellan gum case (2007)
M. Caggioni A, P. T. Spicer, D. L. Blair, S. E. Lindberg, D. A. Weitz
Particle tracking microrheology is used to study the effect of a constant applied shear during gelation of aqueous gellan gum with a monovalent salt. Shear modifies the gellan gum hydrogel...
Directionality of glioblastoma invasion in a 3d in vitro experiment (2006)
Stein, A M, Vader, D A, Deisboeck, T S, Chiocca, E A, Sander, L M, Weitz, D A
Glioblastoma is the most malignant form of brain cancer. It is extremely invasive; the mechanisms that govern invasion are not well understood. To better understand the process of invasion, we...
Microrheology Probes Length Scale Dependent Rheology (2006)
Liu, J., Gardel, M. L., Kroy, K., Frey, E., Hoffman, Brenton D, Crocker, John C, ...
We exploit the power of microrheology to measure the viscoelasticity of entangled F-actin solutions at different length scales from 1 to 100 µm over a wide frequency range. We compare the behavior...
Stress-Dependent Elasticity of Composite Actin Networks as a Model for Cell Behavior (2006)
Gardel, M. L, Nakamura, F., Hartwig, J., Crocker, John C, Stossel, T. P, Weitz, D. A
Networks of filamentous actin cross-linked with the actin-binding protein filamin A exhibit remarkable strain stiffening leading to an increase in differential elastic modulus by several orders of...
Nonlinear viscoelasticity of metastable complex fluids,” Europhys (2006)
K. Miyazaki, H. M. Wyss, D. A. Weitz, D. R. Reichman
PACS. 83.60.Rs – Shear rate-dependent structure (shear thinning and shear thickening).
Nonlinear viscoelasticity of metastable complex fluids (2005)
Miyazaki, Kunimasa, Wyss, Hans M., Weitz, D. A., Reichman, David R.
Many metastable complex fluids such as colloidal glasses and gels show distinct nonlinear viscoelasticity with increasing oscillatory-strain amplitude; the storage modulus decreases monotonically as...
Filamin-A and Rheological Properties of Cultured Melanoma Cells (2005)
Srboljub M. Mijailovich, Milos Kojic, Miroslav Zivkovic, Ben Fabry, Jeffrey J, C. T. Mierke, ...
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ARTICLES Weak Correlations between Local Density and Dynamics near the Glass Transition † (2005)
J. C. Conrad, F. W. Starr, D. A. Weitz
We perform experiments on two different dense colloidal suspensions with confocal microscopy to probe the relationship between local structure and dynamics near the glass transition. We calculate the...
Mechanical Properties of Xenopus Egg Cytoplasmic Extracts (2005)
M. T. Valentine, Z. E. Perlman, D. A. Weitz
ABSTRACT Cytoplasmic extracts prepared from Xenopus laevis eggs are used for the reconstitution of a wide range of processes in cell biology, and offer a unique environment in which to investigate...
Glasslike Arrest in Spinodal Decomposition as a Route to Colloidal Gelation (2004)
Manley, S., Wyss, H. M., Miyazaki, K., Conrad, J. C., Trappe, V., Kaufman, L. J., ...
Colloid-polymer mixtures can undergo spinodal decomposition into colloid-rich and colloid-poor regions. Gelation results when interconnected colloid-rich regions solidify. We show that this occurs...
M. T. Valentine, Z. E. Perlman, J. H. Shin, P. Matsudaira, T. J. Mitchison, ...
ABSTRACT Characterization of the properties of complex biomaterials using microrheological techniques has the promise of providing fundamental insights into their biomechanical functions; however,...
Microrheology of Entangled F-Actin Solutions (2003)
Gardel, M. L., Valentine, M. T., Crocker, John C, Bausch, A. R., Weitz, D. A.
We measure the viscoelasticity of entangled F-actin over length scales between 1 and 100 µm using one- and two-particle microrheology, and directly identify two distinct microscopic contributions...
Grain Boundary Scars and Spherical Crystallography (2003)
Bausch, A. R., Bowick, M. J., Cacciuto, A., Dinsmore, A. D., Hsu, M. F., Nelson, D. R., ...
We describe experimental investigations of the structure of two-dimensional spherical crystals. The crystals, formed by beads self-assembled on water droplets in oil, serve as model systems for...
Microrheology of entangled F-actin solutions (2003)
M. L. Gardel, M. T. Valentine, J. C. Crocker, A. R. Bausch, D. A. Weitz
We measure the viscoelasticity of entangled F-actin over length scales between 1 and 100 µm using one- and two-particle microrheology and directly identify two distinct microscopic contributions to...
Universal features of the fluid to solid transition for attractive colloidal particles (2003)
V. Prasad, V. Trappe, A. D. Dinsmore, P. N. Segre, L. Cipelletti, D. A. Weitz
This paper describes the applicability of the jamming state diagram, and highlights those regions where the fluid to solid transition is still poorly understood. It also presents new data for...
Universal Non-Diffusive Slow Dynamics in Aging Soft Matter (2003)
Luca Cipelletti, Laurence Ramos, S. Manley, E. Pitard, D. A. Weitz, Eugene E. Pashkovski, ...
this paper, we present light scattering measurements of the ultraslow dynamics and the aging of several soft matter jammed systems. Remarkably, we find that for all systems the dynamic structure...
Microrheology of polyethylene oxide using diffusing wave spectroscopy and single scattering (2002)
Dasgupta, Bivash R., Tee, Shang-You, Crocker, John C, Frisken, B. J., Weitz, D. A.
Experiments investigating the local viscoelastic properties of a simple uncross-linked flexible polymer are performed on polyethylene oxide solutions in the semidilute regime using polystyrene beads...
Properties of cage rearrangements observed near the colloidal glass transition (2002)
We use confocal microscopy to study the motions of particles in concentrated colloidal systems. Near the glass transition, diffusive motion is inhibited, as particles spend time trapped in transient...
Colloidosomes: Selectively Permeable Capsules Composed of Colloidal Particles (2002)
A. D. Dinsmore, Ming F. Hsu, M. G. Nikolaides, Manuel Marquez, A. R. Bausch, D. A. Weitz
ical loads and to enable release by defined shear rates; and control of compatibility allows encapsulation of fragile and sensitive ingredients, such as biomolecules and cells. Precise control of all...
Subdiffusion and the cage effect studied near the colloidal glass transition (2002)
Thedyna[][ ofa gla33C2B7;8C maa33C slowgrea;7 nea thegla7 tra38FC2B7 a molecula motion becomes inhibited. We useconfoca microscopy toinvestigaF the motion ofcolloida paloida nea thecolloida glao...
Subdiffusion and the cage effect studied near the colloidal glass transition (2001)
The dynamics of a glass-forming material slow greatly near the glass transition, and molecular motion becomes inhibited. We use confocal microscopy to investigate the motion of colloidal particles...
Properties of cage rearrangements observed near the colloidal glass transition (2001)
We use confocal microscopy to study the motions of particles in concentrated colloidal systems. Near the glass transition, diffusive motion is inhibited, as particles spend time trapped in transient...
The Effect of Solvent and Ions on the Structure and Rheological Properties of Guar Solutions (2001)
M. R. Gittings, Luca Cipelletti, V. Trappe, D. A. Weitz, M. In, J. Lal
this paper we report the results of rheological and scattering studies on the effect of IPA and various salts on the viscoelastic properties and the structure of guar solutions in H 2 O. Previous...
Rheology of F-Actin Solutions Determined from Thermally-Driven Tracer Motion (2000)
T. G. Mason, T. Gisler, K. Kroy, E. Frey, D. A. Weitz
We report measurements of the frequency-dependent complex shear modulus of semidilute F-actin solutions based on optical observations of the thermally-excited motion of monodisperse tracer...
"Wave transport in random media: The ballistic to diffusive transition" (1999)
Zhang, Z.Q., Jones, I.P., Schriemer, H.P., Page, J.H., Weitz, D.A., Ping, Sheng
Electrostatic Repulsion of Positively Charged Vesicles and Negatively Charged Objects (1999)
Helim Aranda-Espinoza, Yi Chen, Nily Dan, T. C. Lubensky, Philip Nelson, Laurence Ramos, ...
this paper was motivated by two sets of experimental observations that defy the familiar rule above #2, 3#. Bilayer vesicles were prepared from a mixture of cationic #positively charged# and neutral...
Monodisperse Emulsion Generation Via Drop Break-Off in a Co-Flowing Stream (1999)
P.B. Umbanhowar, V. Prasad, D.A. Weitz
Wedescribe an experimental technique for the production of highly monodisperse emulsions #with minimumachievable polydispersities # # 3##. The phase to be dispersed is introduced into a co-#owing,...
A Model for the Elasticity of Compressed Emulsions (1996)
Lacasse, Martin-Daniel, Grest, Gary S., Levine, Dov, Mason, T. G., Weitz, D. A.
We present a new model to describe the unusual elastic properties of compressed emulsions. The response of a single droplet under compression is investigated numerically for different Wigner-Seitz...
Diffusing-wave spectroscopy: dynamic light scattering in the multiple scattering limit (1990)
Pine, D.J., Weitz, D.A., Zhu, J.X., Herbolzheimer, E.
Dynamic light scattering is extended to optically thick (opaque) media which exhibit a very high degree of multiple scattering. This new technique, called diffusing-wave spectroscopy (DWS), exploits...
Diffusing-wave spectroscopy: dynamic light scattering in the multiple scattering limit (1990)
Pine, D.J., Weitz, D.A., Zhu, J.X., Herbolzheimer, E.
Dynamic light scattering is extended to optically thick (opaque) media which exhibit a very high degree of multiple scattering. This new technique, called diffusing-wave spectroscopy (DWS), exploits...
Diffusing-wave spectroscopy: dynamic light scattering in the multiple scattering limit (1990)
Pine, D.J., Weitz, D.A., Zhu, J.X., Herbolzheimer, E.
Dynamic light scattering is extended to optically thick (opaque) media which exhibit a very high degree of multiple scattering. This new technique, called diffusing-wave spectroscopy (DWS), exploits...
Elsevier Science Publishers B.V., Amsterdam Universality laws in coagulation (1989)
D. A. Weitz, M. Y. Lin, H. M. Lindsay
We show that the process of irreversible, kinetic colloid aggregation exhibits universal behavior, independent of the detailed chemical nature of the colloidal particles. Modem methods of statistical...
CHARGE TRANSFER FROM TETRATHIAFULVALENE (TTF) TO SILVER AND GOLD SURFACES (1982)
Sandroff, C.J., Weitz, D.A., Herschbach, Dudley R.
$^{1}$Lecture notes in Physics, Series No. 65 (Springer-Verlag, Berlin 1997) ``Organic Conductors and Semiconductors,'' edited by L. Pal, G. Gruner, A. Janossy, and J. Solyom. $^{2}$R. Bozio, I....
Trojan particles: Large porous carriers of nanoparticles for drug delivery
Tsapis, N., Bennett, D., Jackson, B., Weitz, D. A., Edwards, D. A.
We have combined the drug release and delivery potential of nanoparticle (NP) systems with the ease of flow, processing, and aerosolization potential of large porous particle (LPP) systems by spray...
Engineering asymmetric vesicles
Pautot, Sophie, Frisken, Barbara J., Weitz, D. A.
Vesicles are bilayers of lipid molecules enclosing a fixed volume of aqueous solution. Ubiquitous in cells, they can be produced in vitro to study the physical properties of biological membranes and...
Relating microstructure to rheology of a bundled and cross-linked F-actin network in vitro
Shin, J. H., Gardel, M. L., Mahadevan, L., Matsudaira, P., Weitz, D. A.
The organization of individual actin filaments into higher-order structures is controlled by actin-binding proteins (ABPs). Although the biological significance of the ABPs is well documented, little...
Colloid Surface Chemistry Critically Affects Multiple Particle Tracking Measurements of Biomaterials
Valentine, M. T., Perlman, Z. E., Gardel, M. L., Shin, J. H., Matsudaira, P., Mitchison, T. J., ...
Characterization of the properties of complex biomaterials using microrheological techniques has the promise of providing fundamental insights into their biomechanical functions; however, precise...
Mechanical Properties of Xenopus Egg Cytoplasmic Extracts
Valentine, M. T., Perlman, Z. E., Mitchison, T. J., Weitz, D. A.
Cytoplasmic extracts prepared from Xenopus laevis eggs are used for the reconstitution of a wide range of processes in cell biology, and offer a unique environment in which to investigate the role of...
Kaufman, L. J., Brangwynne, C. P., Kasza, K. E., Filippidi, E., Gordon, V. D., Deisboeck, T. S., ...
We study the growth and invasion of glioblastoma multiforme (GBM) in three-dimensional collagen I matrices of varying collagen concentration. Phase-contrast microscopy studies of the entire GBM...
Gardel, M. L., Nakamura, F., Hartwig, J. H., Crocker, J. C., Stossel, T. P., Weitz, D. A.
We show that actin filaments, shortened to physiological lengths by gelsolin and cross-linked with recombinant human filamins (FLNs), exhibit dynamic elastic properties similar to those reported for...
Trojan particles: Large porous carriers of nanoparticles for drug delivery
Tsapis, N., Bennett, D., Jackson, B., Weitz, D. A., Edwards, D. A.
We have combined the drug release and delivery potential of nanoparticle (NP) systems with the ease of flow, processing, and aerosolization potential of large porous particle (LPP) systems by spray...
Engineering asymmetric vesicles
Pautot, Sophie, Frisken, Barbara J., Weitz, D. A.
Vesicles are bilayers of lipid molecules enclosing a fixed volume of aqueous solution. Ubiquitous in cells, they can be produced in vitro to study the physical properties of biological membranes and...
Relating microstructure to rheology of a bundled and cross-linked F-actin network in vitro
Shin, J. H., Gardel, M. L., Mahadevan, L., Matsudaira, P., Weitz, D. A.
The organization of individual actin filaments into higher-order structures is controlled by actin-binding proteins (ABPs). Although the biological significance of the ABPs is well documented, little...
Colloid Surface Chemistry Critically Affects Multiple Particle Tracking Measurements of Biomaterials
Valentine, M. T., Perlman, Z. E., Gardel, M. L., Shin, J. H., Matsudaira, P., Mitchison, T. J., ...
Characterization of the properties of complex biomaterials using microrheological techniques has the promise of providing fundamental insights into their biomechanical functions; however, precise...
Mechanical Properties of Xenopus Egg Cytoplasmic Extracts
Valentine, M. T., Perlman, Z. E., Mitchison, T. J., Weitz, D. A.
Cytoplasmic extracts prepared from Xenopus laevis eggs are used for the reconstitution of a wide range of processes in cell biology, and offer a unique environment in which to investigate the role of...
Kaufman, L. J., Brangwynne, C. P., Kasza, K. E., Filippidi, E., Gordon, V. D., Deisboeck, T. S., ...
We study the growth and invasion of glioblastoma multiforme (GBM) in three-dimensional collagen I matrices of varying collagen concentration. Phase-contrast microscopy studies of the entire GBM...
Gardel, M. L., Nakamura, F., Hartwig, J. H., Crocker, J. C., Stossel, T. P., Weitz, D. A.
We show that actin filaments, shortened to physiological lengths by gelsolin and cross-linked with recombinant human filamins (FLNs), exhibit dynamic elastic properties similar to those reported for...
Optimal vein density in artificial and real leaves
Noblin, X., Mahadevan, L., Coomaraswamy, I. A., Weitz, D. A., Holbrook, N. M., Zwieniecki, M. A.
The long evolution of vascular plants has resulted in a tremendous variety of natural networks responsible for the evaporatively driven transport of water. Nevertheless, little is known about the...
Zhou, E. H., Trepat, X., Park, C. Y., Lenormand, G., Oliver, M. N., Mijailovich, S. M., ...
Mechanical robustness of the cell under different modes of stress and deformation is essential to its survival and function. Under tension, mechanical rigidity is provided by the cytoskeletal...