Understanding and Engineering the Nanoparticle Corona and Its Effect on Biological Interfaces

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• published: 24 Apr 2017
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Title: Understanding and Engineering the Nanoparticle Corona and Its Effect on Biological Interfaces Presenter: Prof. Michael Strano, MIT Abstract: Our lab at MIT has been interested in how nanoparticles in general and the 1D and 2D electronic structures of carbon nanotubes and graphene specifically, can be utilized to advance new concepts in molecular detection, including sensors, which we have recently applied to biomedical and agricultural problems. We introduce a method CoPhMoRe or Corona Phase Molecular Recognition1 as a method of discovering synthetic, heteropolymer corona phases that form molecular recognition sites at the nanoparticle interface, selected from a heteropolymer library. We show that certain synthetic heteropolymers, once constrained onto a single-walled carbon nanotube by chemical adsorption, also form a new corona phase that exhibits highly selective recognition for specific molecules. To prove the generality of this phenomenon, we report several examples of heteropolymers–nanotube recognition complexes for riboflavin, L-thyroxine, dopamine, nitric oxide, sugar alcohols, estradiol, as well as proteins such as fibrinogen. An emerging application of such sensor technology from my lab at MIT has been the use of near infrared fluorescent carbon nanotube sensors for in-vivo detection of a variety of biomolecules2. Here, we show that PEG-ligated d(AAAT)7 DNA wrapped SWNT are selective for nitric oxide, a vasodilator of blood vessels, and can be tail vein injected into mice and localized within the viable mouse liver. We demonstrate that a hydrogel encapsulated version of the sensor can remain viable and biocompatable in A129 mice for more than 400 days, opening the possibility of long term, persistent biochemical detection through thick tissue. Lastly, we discuss recent efforts in my laboratory to engineer plant systems using nanoparticles with specifically designed corona phases. We examine the subcellular uptake and kinetic trapping of a wide range of nanoparticles for the first time, using the plant chloroplast as a model system, but validated in vivo in living plants. We find that particle size and the magnitude, but not the sign, of the zeta potential are key in determining whether a particle is spontaneously and kinetically trapped within the organelle, despite the negative zeta potential of the envelope. We develop a mathematical model of this lipid exchange envelope and penetration (LEEP) mechanism, which agrees well with observations of this size and zeta potential dependence. The theory predicts a critical particle size below which the mechanism fails at all zeta potentials, explaining why nanoparticles are critical for this process. LEEP constitutes a powerful particulate transport and localization mechanism for nanoparticles within the plant system. Bio: Professor Michael S. Strano is currently the Carbon P. Dubbs Professor of Chemical Engineering at the Massachusetts Institute of Technology. He received his B.S from Polytechnic University in Brooklyn, NY and Ph.D. from the University of Delaware both in Chemical Engineering. He was a post doctoral research fellow at Rice University in the departments of Chemistry and Physics under the guidance of Nobel Laureate Richard E. Smalley. From 2003 to 2007, Michael was an Assistant Professor in the Department of Chemical and Biomolecular Engineering at the University of Illinois at Urbana-Champaign before moving to MIT. His research focuses on biomolecule/nanoparticle interactions and the surface chemistry of low dimensional systems, nano-electronics, nanoparticle separations, and applications of vibrational spectroscopy to nanotechnology. Michael recently completed a two year commitment with the Defense Science Study Group (DSSG) and is a current member of the Defense Science Board (DSB). He is the recipient of numerous awards for his work from 2005 to the present, including being recently named one of the world’s most influential scientific minds by Thomson Reuters. ________________ 1. Zhang, JQ et. al. Molecular recognition using corona phase complexes made of synthetic polymers adsorbed on carbon nanotubes. Nature Nanotechnology, 8, 12, 2013, 959-968 2. Iverson, NM, et. al. In vivo biosensing via tissue-localizable near-infrared-fluorescent single-walled carbon nanotubes. Nature Nanotechnology, 8, 11, 2013, 873-880