S.C. O’Hern, D. Jang, S. Bose, J.-C. Idrobo, Y. Song, T. Laoui, J. Kong, and R. Karnik. Nanofiltration across defect-sealed nanoporous monolayer graphene. Nano Letters, 15, 3254-3260 (2015).
We develop a multi-scale method to seal defects in graphene and demonstrate nanofiltration using centimeter-scale single-layer graphene membranes.
R. Karnik. Breakthrough for protons. Nature, 516, 173–175 (2014).
News and Views article on Geim group's work on proton conduction across 2D materials.
J. Lim, A. Swami, L. M. Gilson, S. Chopra, S. Choi, J. Wu, R. Langer, R. Karnik, and O. C. Farokhzad. Ultra-high throughput synthesis of nanoparticles with homogeneous size distribution using a coaxial turbulent jet mixer. ACS Nano, 8, 6056–6065 (2014).
We develop a simple millifluidic system that can be made from off-the-shelf components for controlled synthesis of nanoparticles at high throughputs.
M. S. H. Boutilier, J. Lee, V. Chambers, V. Venkatesh, and R. Karnik. Water filtration using plant xylem. PLoS ONE, 9, e89934 (2014).
We demonstrate that a small piece of sapwood can filter out more than 99 percent of the bacteria E. coli from water. MIT news
C. Sun, M. S. H. Boutilier, H. Au, P. Poesio, B. Bai, N. G. Hadjiconstantinou, and R. Karnik. Mechanisms of molecular permeation through nanoporous graphene membranes. Langmuir, 30, 675-682 (2014).
We systematically study gas permeation through graphene and develop a model to delineate regimes where selectivity can be obtained regardless of the presence of defects.
J. Lee, M.S.H. Boutilier, V. Chambers, V. Venkatesh, and R. Karnik. Water filtration using plant xylem. arXiv.1310.4814.
We show that plant xylem from the sapwood of coniferous trees can remove bacteria from water by simple pressure-driven filtration.
M.A. Cartas-Ayala, L. Gilson, C. Shen, and R. Karnik. Oscillations in light-triggered logic microfluidic circuit. Microsystem Technologies DOI 10.1007/s00542-013-1899-4 (2013).
We report observations of oscillations in a microfluidic circuit capable of sorting curable droplets on demand by triggering the circuit with UV-light.
P. M. Valencia, E. M. Pridgen, B. Perea, S. Gadde, C. Sweeney, P. W. Kantoff, S. J. Lippard, R. Langer, R. Karnik, and O. C. Farokhzad.
Synergistic cytotoxicity of irinotecan and cisplatin in dual-drug PSMA-targeted polymeric nanoparticles. Nanomedicine, 8, 687-698 (2013).
We report synergistic toxicity due to targeted dual-drug encapsulating nanoparticles synthesized by microfluidic rapid mixing.
Cho, W. K., Ankrum, J. A., Guo, D., Chester, S. A., Yang, S. Y., Kashyap, A., Campbell, G. A., Wood, R. J., Rijal, R. K., Karnik, R., Langer, R. and J. M. Karp.
Microstructured barbs on the North American porcupine quill enable easy tissue penetration and difficult removal. Proc. Natl. Acad. Sci. (USA), 109, 21289-21294 (2012).
We study the penetration and adhesion mechanism of porcupine quills, which reveals that barbs reduce penetration force by cutting the tissue, and barbs at different positions on the quill cooperate to maximize adhesion.
W. Zhao, C. H. Cui, S. Bose, D. Guo, C. Shen, W. P. Wong, K. Halvorsen, O. C. Farokhzad, G. S. L. Teo, J. Philips, D. M. Dorfman, R. Karnik, and J. M. Karp.
A bioinspired multivalent DNA network for capture and release of cells. Proc. Natl. Acad. Sci. (USA), 109, 19626-19631 (2012).
We report high-throughput capture and release of cells from blood enabled by long DNA aptamers in microfluidic devices.
S. C. O'Hern, C. A. Stewart, M. S. H. Boutilier, J.-C. Idrobo, S. Bhaviripudi, S. K. Das, J. Kong, T. Laoui, M. Atieh, and R. Karnik.
Selective molecular transport through intrinsic defects in a single layer of CVD graphene. ACS Nano, 6, 10130-10138 (2012).
We fabricate centimeter-scale membranes comprising s single layer of CVD graphene on a porous support and show selective transport due to defects present in the graphene. This work is potentially the first to demonstrate selective transport through macroscopic areas of a single sheet of graphene.
P. M. Valencia, O. C. Farokhzad, R. Karnik, and R. Langer.
Microfluidic technologies for accelerating the clinical translation of nanoparticles. Nature Nanotechnology 7, 623-629 (2012).
We discuss in this review how microfluidic technologies can tackle some of the challenges in translating nanoparticles to the clinic. This article outlines these advances and offers an assessment of the near- and long-term impact of microfluidic technologies in nanomedicine.
E. N. Wang and R. Karnik.
Water desalination: Graphene cleans up water. Nature Nanotechnology 7, 552-554 (2012).
We provide a perspective on Cohen-Tanugi and Grossman's work on the promise of graphene for water desalination at throughputs much higher than state-of-the-art membranes.
J. Lee, F. Rahman, T. Laoui, and R. Karnik.
Bubble-induced damping in displacement-driven microfluidic flows. Physical Review E 86, 026301 (2012).
Bubble damping in displacement-driven microfluidic flows was theoretically and experimentally investigated for microfluidic networks. The model was able to predict experimentally observed damping of fluctuations with excellent agreement. A flowmeter with high resolution was demonstrated as an application of the bubble-aided stabilization.
C. Duan, R. Karnik, M. Lu and A. Majumdar.
Evaporation-induced cavitation in nanofluidic channels. Proc. Natl. Acad. Sci. (USA), 109, 3688-3693 (2012).
We demonstrate cavitation phenomenon in evaporating nanofluidic channels that result in fast evaporation kinetics. Bubbles formed at the entrance of the nanochannels rapidly migrate to certain fixed positions within the channels that depend only on nanochannel height. The dynamics reflect interplay of thermocapillary flow and convection.
S. Choi, J. M. Karp, and R. Karnik.
Cell sorting by deterministic cell rolling. Lab on a Chip 12, 1427-1430 (2012). (Front cover article)
This communication presents the concept of deterministic cell rolling, which leverages transient cell-surface molecular interactions that mediate cell rolling to sort cells with high purity and efficiency in a single step.
D. Sarkar, J. A. Spencer, J. A. Phillips, W. Zhao, S. Schafer, D. P. Spelke, L. J. Mortensen, J. P. Ruiz, P. K. Vemula, R. Sridharan, S. Kumar, R. Karnik, C. P. Lin, and J. M. Karp.
Engineered cell homing. Blood 118, e184-e191 (2011).
W. Zhao, W. Loh, I. A. Droujinine, W. Teo, N. Kumar, S. Schafer, C. H. Cui, L. Zhang, D. Sarkar, R. Karnik, and J. M. Karp.
Mimicking the inflammatory cell adhesion cascade by nucleic acid aptamer programmed cell-cell interactions. The FASEB Journal 25, 3045-3056 (2011).
T. Humplik, J. Lee, S. C. O'Hern, B. A. Fellman, M. A. Baig, S. F. Hassan, M. A. Atieh, F. Rahman, T. Laoui, R. Karnik, and E. N. Wang.
Nanostructured materials for water desalination. Nanotechnology 22, 292001 (2011).
W. Zhao, S. Schafer,J. Choi, Y. J. Yamanaka, M. L. Lombardi, S. Bose, A. L. Carlson, J. A. Phillips, W. Teo, I. A. Droujinine, C. Cui, R. K. Jain, J. Lammerding, J. C. Love, C. P. Lin, D. Sarkar, R. Karnik, and J. M. Karp.
Cell-surface sensors for real-time probing of cellular environments. Nature Nanotechnology 6, 524-531 (2011).
Conferences & Presentations