Xia, J. ; Yuan, Y. ; Wu, H. ; Huang, Y. ; Weitz, D. A. Decoupling the effects of nanopore size and surface roughness on the attachment, spreading and differentiation of bone marrow-derived stem cells. Biomaterials 2020. Publisher's Version
Adams, L. L. A. ; Lee, D. ; Mei, Y. F. ; Weitz, D. A. ; Solovev, A. A. Nanoparticle‐Shelled Catalytic Bubble Micromotor. Advanced Materials Interfaces 2020, 1901583. Publisher's Version adams2020.pdf
Tiribocchi, A. ; Montessori, A. ; Aime, S. ; Milani, M. ; Lauricella, M. ; Succi, S. ; Weitz, D. Novel nonequilibrium steady states in multiple emulsions. Physics of Fluids 2020, 32, 017102. Publisher's VersionAbstract
We numerically investigate the rheological response of a noncoalescing multiple emulsion under a symmetric shear flow. We find that the dynamics significantly depends on the magnitude of the shear rate and on the number of the encapsulated droplets, two key parameters whose control is fundamental to accurately select the resulting nonequilibrium steady states. The double emulsion, for instance, attains a static steady state in which the external droplet stretches under flow and achieves an elliptical shape (closely resembling the one observed in a sheared isolated fluid droplet), while the internal one remains essentially unaffected. Novel nonequilibrium steady states arise in a multiple emulsion. Under low/moderate shear rates, for instance, the encapsulated droplets display a nontrivial planetarylike motion that considerably affects the shape of the external droplet. Some features of this dynamic behavior are partially captured by the Taylor deformation parameter and the stress tensor. Besides a theoretical interest on its own, our results can potentially stimulate further experiments, as most of the predictions could be tested in the lab by monitoring droplets’ shapes and position over time.
Nawar, S. ; Stolaroff, J. K. ; Ye, C. ; Wu, H. ; Nguyen, D. T. ; Xin, F. ; Weitz, D. A. Parallelizable microfluidic dropmakers with multilayer geometry for the generation of double emulsions. Lab on a Chip 2020, 20, 147–154. Publisher's VersionAbstract
We present a multilayer dropmaker geometry that enables the modular fabrication of microfluidic devices containing precisely patterned channel surface wettability. The platform is used for the scalable production of uniform double emulsion drops. , Microfluidic devices enable the production of uniform double emulsions with control over droplet size and shell thickness. However, the limited production rate of microfluidic devices precludes the use of monodisperse double emulsions for industrial-scale applications, which require large quantities of droplets. To increase throughput, devices can be parallelized to contain many dropmakers operating simultaneously in one chip, but this is challenging to do for double emulsion dropmakers. Production of double emulsions requires dropmakers to have both hydrophobic and hydrophilic channels, requiring spatially precise patterning of channel surface wettability. Precise wettability patterning is difficult for devices containing multiple dropmakers, posing a significant challenge for parallelization. In this paper, we present a multilayer dropmaker geometry that greatly simplifies the process of producing microfluidic devices with excellent spatial control over channel wettability. Wettability patterning is achieved through the independent functionalization of channels in each layer prior to device assembly, rendering the dropmaker with a precise step between hydrophobic and hydrophilic channels. This device geometry enables uniform wettability patterning of parallelized dropmakers, providing a scalable approach for the production of double emulsions.
Shi, W. ; Chen, X. ; Li, B. ; Weitz, D. A. Spontaneous Creation of Anisotropic Polymer Crystals with Orientation-Sensitive Birefringence in Liquid Drops. ACS Applied Materials & Interfaces 2020, acsami.9b17308. Publisher's VersionAbstract
It remains a grand challenge to prepare anisotropic crystal superstructures with sensitive optical properties in polymer science and materials field. This study demonstrates that semicrystalline polymers develop into anisotropic hollow spherulitic crystals spontaneously at interfaces of liquid drops. In contrast to conventional spherulites with centrosymmetric optics and grain boundaries, these anisotropic spherulitic crystals have vanished boundary defects, tunable aspect ratios, and noncentrosymmetric, orientationsensitive birefringence. The experimental finding is elaborated in poly(L-lactic acid) crystals and is further verified in a broad class of semicrystalline polymers, irrespective of molecular chirality, chemical constitution, or interfacial modification. The facile methods and general mechanism revealed in this study shed light on developing new types of optical microdevices and synthesis of anisotropic semicrystalline particles from liquid emulsions.
Cao, T. ; Wang, Y. ; Tao, Y. ; Zhang, L. ; Zhou, Y. - L. ; Zhang, X. - X. ; Heyman, J. A. ; Weitz, D. A. DNAzyme-powered nucleic acid release from solid supports. Chemical Communications 2020, 56, 647–650. Publisher's VersionAbstract
Here, we demonstrate use of a Mg 2+ -dependent, site-specific DNA enzyme (DNAzyme) to cleave oligos from polyacrylamide gel beads, which is suitable for use in drop-based assays. , Here, we demonstrate use of a Mg 2+ -dependent, site-specific DNA enzyme (DNAzyme) to cleave oligos from polyacrylamide gel beads, which is suitable for use in drop-based assays. We show that cleavage efficiency is improved by use of a tandem-repeat cleavage site. We further demonstrate that DNAzyme-released oligos function as primers in reverse transcription of cell-released mRNA.
Chowdhury, M. S. ; Zheng, W. ; Kumari, S. ; Heyman, J. ; Zhang, X. ; Dey, P. ; Weitz, D. A. ; Haag, R. Dendronized fluorosurfactant for highly stable water-in-fluorinated oil emulsions with minimal inter-droplet transfer of small molecules. Nature Communications 2019, 10. Publisher's Version
Gerber, G. ; Bensouda, M. ; Weitz, D.  A. ; Coussot, P. Self-Limited Accumulation of Colloids in Porous Media. Physical Review Letters 2019, 123. Publisher's Version gerber2019.pdf
Zhang, W. ; Qu, L. ; Pei, H. ; Qin, Z. ; Didier, J. ; Wu, Z. ; Bobe, F. ; Ingber, D. E. ; Weitz, D. A. Controllable Fabrication of Inhomogeneous Microcapsules for Triggered Release by Osmotic Pressure. Small 2019, 1903087. zhang2019b.pdf
Zhu, Z. ; Liu, J. - D. ; Liu, C. ; Wu, X. ; Li, Q. ; Chen, S. ; Zhao, X. ; Weitz, D. A. Microfluidics-Assisted Assembly of Injectable Photonic Hydrogels toward Reflective Cooling. Small 2019, 1903939. zhu2019.pdf
Mao, A. S. ; Ozkale, B. ; Shah, N. J. ; Vining, K. H. ; Descombes, T. ; Zhang, L. ; Tringides, C. M. ; Wong, S. - W. ; Shin, J. - W. ; et al. Scadden, D. T. Programmable microencapsulation for enhanced mesenchymal stem cell persistence and immunomodulation. Proceedings of the National Academy of Sciences 2019, 116, 15392–15397. mao2019.pdf
Du, J. ; Fan, Y. ; Guo, Z. ; Wang, Y. ; Zheng, X. ; Huang, C. ; Liang, B. ; Gao, L. ; Cao, Y. ; et al. Chen, Y. Compression Generated by a 3D Supracellular Actomyosin Cortex Promotes Embryonic Stem Cell Colony Growth and Expression of Nanog and Oct4. Cell Systems 2019, 9 214-220.e5. du2019.pdf
Chen, R. ; Liu, J. ; Yang, C. ; Weitz, D. A. ; He, H. ; Li, D. ; Chen, D. ; Liu, K. ; Bai, H. Transparent Impact-Resistant Composite Films with Bioinspired Hierarchical Structure. ACS Applied Materials & Interfaces 2019, 11, 23616-23622. chen2019.pdf
Kong, L. ; Chen, R. ; Wang, X. ; Zhao, C. - X. ; Chen, Q. ; Hai, M. ; Chen, D. ; Yang, Z. ; Weitz, D. A. Controlled co-precipitation of biocompatible colorant-loaded nanoparticles by microfluidics for natural color drinks. Lab Chip 2019. Publisher's Version kong2019.pdf
Hwang, H. ; Weitz, D. A. ; Spaepen, F. Direct observation of crystallization and melting with colloids. Proc. Natl. Acad. Sci. U.S.A. 2019, 116, 1180–1184. Publisher's Version hwang2019.pdf
Sun, Z. ; Yang, C. ; Eggersdorfer, M. ; Cui, J. ; Li, Y. ; Hai, M. ; Chen, D. ; Weitz, D. A. A general strategy for one-step fabrication of biocompatible microcapsules with controlled active release. Chin. Chem. Lett. 2019. Publisher's Version sun2019.pdf
Zhu, H. ; Nawar, S. ; Werner, J. G. ; Liu, J. ; Huang, G. S. ; Mei, Y. F. ; Weitz, D. A. ; Solovev, A. A. Hydrogel micromotors with catalyst-containing liquid core and shell. J. Phys.: Condens. Matter 2019, 31, 214004. Publisher's Version zhu2018.pdf
Montessori, A. ; Lauricella, M. ; Stolovicki, E. ; Weitz, D. A. ; Succi, S. Jetting to dripping transition: Critical aspect ratio in step emulsifiers. Physics of Fluids 2019, 31, 021703. Publisher's Version montessori2019.pdf
Haney, B. ; Chen, D. ; Cai, L. - H. ; Weitz, D. ; Ramakrishnan, S. Millimeter-Size Pickering Emulsions Stabilized with Janus Microparticles. Langmuir 2019. Publisher's Version haney2019.pdf
Zhang, H. ; Cui, W. ; Qu, X. ; Wu, H. ; Qu, L. ; Zhang, X. ; Makila, E. ; Salonen, J. ; Zhu, Y. ; Yang, Z. ; et al. Photothermal-responsive nanosized hybrid polymersome as versatile therapeutics codelivery nanovehicle for effective tumor suppression. Proc. Natl. Acad. Sci. U.S.A. 2019, 116, 7744–7749. Publisher's Version zhang2019.pdf