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920 results on '"Han, Jongyoon"'

301. Analytical description of Ogston-regime biomolecule separation using and nanopores

Author

Massachusetts Institute of Technology. Department of Biological Engineering, Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology. Department of Mechanical Engineering, Hadjiconstantinou, Nicolas, Han, Jongyoon, Li, Zi Rui, Liu, Gui Rong, Cheng, Yuan, Chen, Yu Zong, Wang, Jian-Sheng, Massachusetts Institute of Technology. Department of Biological Engineering, Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology. Department of Mechanical Engineering, Hadjiconstantinou, Nicolas, Han, Jongyoon, Li, Zi Rui, Liu, Gui Rong, Cheng, Yuan, Chen, Yu Zong, and Wang, Jian-Sheng

Abstract

We present a theoretical model describing Ogston (pore size comparable to or larger than the characteristic molecular dimension) sieving of rigid isotropic and anisotropic biomolecules in nanofluidic molecular filter arrays comprising of alternating deep and shallow regions. Starting from a quasi-one-dimensional drift-diffusion description, which captures the interplay between the driving electric force, entropic barrier and molecular diffusion, we derive explicit analytical results for the effective mobility and trapping time. Our results elucidate the effects of field strength, device geometry and entropic barrier height, providing a robust tool for the design and optimization of nanofilter/nanopore systems. Specifically, we show that Ogston sieving becomes negligible when the length of shallow region becomes sufficiently small, mainly due to efficient diffusional transport through the short shallow region. Our theoretical results are in line with experimental observations and provide important design insight for nanofluidic systems., Singapore-MIT Alliance SMA -II, Computational Engineering CE program

Published
2010

302. Transport of biomolecules in asymmetric nanofilter arrays

Author

Massachusetts Institute of Technology. Department of Biological Engineering, Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science, Han, Jongyoon, Hadjiconstantinou, Nicolas, Liu, G. R., Li, Zi Rui, Chen, Yu Zong, Wang, Jian-Sheng, Massachusetts Institute of Technology. Department of Biological Engineering, Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science, Han, Jongyoon, Hadjiconstantinou, Nicolas, Liu, G. R., Li, Zi Rui, Chen, Yu Zong, and Wang, Jian-Sheng

Abstract

We propose a theoretical model for describing the electric-field-driven migration of rod-like biomolecules in nanofilters comprising a periodic array of shallow passages connecting deep wells. The electrophoretic migration of the biomolecules is modeled as transport of point-sized Brownian particles, with the orientational degree of freedom captured by an entropy term. Using appropriate projections, the formulation dimensionality is reduced to one physical dimension, requiring minimal computation and making it ideal for device design and optimization. Our formulation is used to assess the effect of slanted well walls on the energy landscape and resulting molecule mobility. Using this approach, we show that asymmetry in the well shape, such as a well with one slanted and one vertical wall, may be used for separation using low-frequency alternating-current fields because the mobility of a biomolecule is different in the two directions of travel. Our results show that, compared to methods using direct-current fields, the proposed method remains effective at higher field strengths and can achieve comparable separation using a significantly shorter device.

Published
2009

308. ADAM-10 and -17 regulate endometriotic cell migration via concerted ligand and receptor shedding feedback on kinase signaling

Author

Miller, Miles A., primary, Meyer, Aaron S., additional, Beste, Michael T., additional, Lasisi, Zainab, additional, Reddy, Sonika, additional, Jeng, Karen W., additional, Chen, Chia-Hung, additional, Han, Jongyoon, additional, Isaacson, Keith, additional, Griffith, Linda G., additional, and Lauffenburger, Douglas A., additional

Published
2013
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311. Isoporous Micro/Nanoengineered Membranes

Author

Warkiani, Majid Ebrahimi, primary, Bhagat, Ali Asgar S., additional, Khoo, Bee Luan, additional, Han, Jongyoon, additional, Lim, Chwee Teck, additional, Gong, Hai Qing, additional, and Fane, Anthony Gordon, additional

Published
2013
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315. Broad spectrum immunomodulation using biomimetic blood cell margination for sepsis therapy.

Author

HouCurrent address: Lee Kong Chian School of Medicine Nanyang Technological University Singapore., Han Wei, Wu, Lidan, Amador-Munoz, Diana P., Vera, Miguel Pinilla, Coronata, Anna, Englert, Joshua A., Levy, Bruce D., Baron, Rebecca M., and Han, Jongyoon

Subjects
SEPTICEMIA treatment, IMMUNOREGULATION, BIOMIMETIC chemicals, BLOOD cells, BLOOD diseases, BLOOD filtration
Abstract

Sepsis represents a systemic inflammatory response caused by microbial infection in blood. Herein, we present a novel comprehensive approach to mitigate inflammatory responses through broad spectrum removal of pathogens, leukocytes and cytokines based on biomimetic cell margination. Using a murine model of polymicrobial sepsis induced by cecal ligation and puncture (CLP), we performed extracorporeal blood filtration with the developed microfluidic blood margination (μBM) device. Circulating bacteremia, leukocytes and cytokines in blood decreased post-filtration and significant attenuation of immune cell and cytokine responses were observed 3–5 days after intervention, indicating successful long-term immunomodulation. A dose-dependent effect on long-term immune cell count was also achieved by varying filtration time. As proof of concept for human therapy, the μBM device was scaled up to achieve ∼100-fold higher throughput (∼150 mL h−1). With further multiplexing, the μBM technique could be applied in clinical settings as an adjunctive treatment for sepsis and other inflammatory diseases. [ABSTRACT FROM AUTHOR]

Published
2016
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317. Nanotechnology in Plastic Surgery

Author

Ibrahim, Ahmed M. S., primary, Gerstle, Theodore L., additional, Rabie, Amr N., additional, Song, Yong-Ak, additional, Melik, Rohat, additional, Han, Jongyoon, additional, and Lin, Samuel J., additional

Published
2012
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319. Molecular Sieving in Periodic Free-Energy Landscapes Created by Patterned Nanofilter Arrays

Author

Fu, Jianping, Yoo, Juhwan, Han, Jongyoon, Fu, Jianping, Yoo, Juhwan, and Han, Jongyoon

Abstract

We present an experimental study of Ogston-like sieving process of rodlike DNA in patterned periodic nanofluidic filter arrays. The electrophoretic motion of DNA through the array is described as a biased Brownian motion overcoming periodically modulated free-energy landscape. A kinetic model, constructed based on the equilibrium partitioning theory and the Kramers theory, explains the field-dependent mobility well. We further show experimental evidence of the crossover from Ogston-like sieving to entropic trapping, depending on the ratio between nanofilter constriction size and DNA size.

Published
2006

322. Continuous-flow macromolecular sieving in slanted nanofilter array: stochastic model and coupling effect of electrostatic and steric hindrance.

Author

Ko, Sung Hee, Park, Pyeong Jun, and Han, Jongyoon

Subjects
*STERIC hindrance, *STOCHASTIC models, *SIEVES, *ONLINE monitoring systems, *ELECTRIC fields, *MACROMOLECULES
Abstract

Microfabricated slanted nanofilter arrays are a promising technology for integrated biomolecule analysis systems such as online monitoring and point-of-care quality validation, due to their continuous-flow and one-step operation capability. However, an incomplete understanding of the system limits the performance and wider applications of slanted nanofilter arrays. In this paper, we present rigorous theoretical and experimental studies on macromolecule sieving in a slanted nanofilter array. From both stochastic and kinetic models, an explicit theoretical solution describing size-dependent molecule sieving was derived, which was validated using experimental sieving results obtained for various sieving conditions. Our results not only detail the relationship between sieving conditions and sieving efficiency but also demonstrate that sieving is affected by multiple hindrance effects (electrostatic hindrance), not steric hindrance alone. There is an optimal sieving condition for achieving the greatest separation efficiency for DNAs of a certain size range. Small DNA has great size selectivity in small nanofilters and in weak electric fields, whereas large DNA is present in large nanofilters and in strong electric fields. This study provides insights into designing a slanted nanofilter array for particular target applications and understanding the sieving principles in the nanofilter array. [ABSTRACT FROM AUTHOR]

Published
2023
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329. Pf155/RESA protein influences the dynamic microcirculatory behavior of ring-stage Plasmodium falciparum infected red blood cells

Author

Diez-Silva, Monica, primary, Park, YongKeun, additional, Huang, Sha, additional, Bow, Hansen, additional, Mercereau-Puijalon, Odile, additional, Deplaine, Guillaume, additional, Lavazec, Catherine, additional, Perrot, Sylvie, additional, Bonnefoy, Serge, additional, Feld, Michael S., additional, Han, Jongyoon, additional, Dao, Ming, additional, and Suresh, Subra, additional

Published
2012
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337. Direct evidence for cancer-cell-autonomous extracellular protein catabolism in pancreatic tumors

Author

Davidson, Shawn M, Jonas, Oliver, Keibler, Mark A, Hou, Han Wei, Luengo, Alba, Mayers, Jared R, Wyckoff, Jeffrey, Del Rosario, Amanda M, Whitman, Matthew, Chin, Christopher R, Condon, Kendall J, Lammers, Alex, Kellersberger, Katherine A, Stall, Brian K, Stephanopoulos, Gregory, Bar-Sagi, Dafna, Han, Jongyoon, Rabinowitz, Joshua D, Cima, Michael J, Langer, Robert, and Vander Heiden, Matthew G

Abstract

Mammalian tissues rely on a variety of nutrients to support their physiological functions. It is known that altered metabolism is involved in the pathogenesis of cancer, but which nutrients support the inappropriate growth of intact malignant tumors is incompletely understood. Amino acids are essential nutrients for many cancer cells that can be obtained through the scavenging and catabolism of extracellular protein via macropinocytosis. In particular, macropinocytosis can be a nutrient source for pancreatic cancer cells, but it is not fully understood how the tumor environment influences metabolic phenotypes and whether macropinocytosis supports the maintenance of amino acid levels within pancreatic tumors. Here we utilize miniaturized plasma exchange to deliver labeled albumin to tissues in live mice, and we demonstrate that breakdown of albumin contributes to the supply of free amino acids in pancreatic tumors. We also deliver albumin directly into tumors using an implantable microdevice, which was adapted and modified from ref. 9. Following implantation, we directly observe protein catabolism and macropinocytosis in situ by pancreatic cancer cells, but not by adjacent, non-cancerous pancreatic tissue. In addition, we find that intratumoral inhibition of macropinocytosis decreases amino acid levels. Taken together, these data suggest that pancreatic cancer cells consume extracellular protein, including albumin, and that this consumption serves as an important source of amino acids for pancreatic cancer cells in vivo.

Published
2017
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