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Abstract
While positively charged nanomaterials induce cytotoxicity in many organisms, much less is known about how the spatial distribution and presentation of molecular surface charge impact nanoparticle-biological interactions. We systematically functionalized diamond nanoparticle surfaces with five different cationic surface molecules having different molecular structures and conformations, including four small ligands and one polymer, and we then probed the molecular-level interaction between these nanoparticles and bacterial cells. Shewanella oneidensis MR-1 was used as a model bacterial cell system to investigate how the molecular length and conformation of cationic surface charges influence their interactions with the Gram-negative bacterial membranes. Nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopy (XPS) demonstrate the covalent modification of the nanoparticle surface with the desired cationic organic monolayers. Surprisingly, bacterial growth-based viability (GBV) and membrane damage assays both show only minimal biological impact by the NPs functionalized with short cationic ligands within the concentration range tested, yet NPs covalently linked to a cationic polymer induce strong cytotoxicity, including reduced cellular viability and significant membrane damage at the same concentration of cationic groups. Transmission electron microscopy (TEM) images of these NP-exposed bacterial cells show that NPs functionalized with cationic polymers induce significant membrane distortion and the production of outer membrane vesicle-like features, while NPs bearing short cationic ligands only exhibit weak membrane association. Our results demonstrate that the spatial distribution of molecular charge plays a key role in controlling the interaction of cationic nanoparticles with bacterial cell membranes and the subsequent biological impact. Nanoparticles functionalized with ligands having different lengths and conformations can have large differences in interactions even while having nearly identical zeta potentials. While the zeta potential is a convenient and commonly used measure of nanoparticle charge, it does not capture essential differences in molecular-level nanoparticle properties that control their biological impact.
Original language | English (US) |
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Pages (from-to) | 10814-10823 |
Number of pages | 10 |
Journal | Journal of the American Chemical Society |
Volume | 142 |
Issue number | 24 |
DOIs | |
State | Published - Jun 17 2020 |
Bibliographical note
Funding Information:This work was supported by the National Science Foundation under the Center for Sustainable Nanotechnology (CHE-1503408). The CSN is part of the Centers for Chemical Innovation Program. N.V.H.-S. acknowledges support through the National Science Foundation Graduate Research Fellowship Program (00039202). XPS studies used facilities and instrumentation supported by NSF through the University of Wisconsin Materials Research Science and Engineering Center (DMR-1720415). The Bruker Avance 600 NMR instrument used in this work was supported by the National Institutes of Health grant S10OD012245. Parts of this work were carried out in the Characterization Facility, University of Minnesota, which receives partial support from the NSF through the MRSEC program.
Publisher Copyright:
© 2020 American Chemical Society.
MRSEC Support
- Shared
PubMed: MeSH publication types
- Journal Article
- Research Support, U.S. Gov't, Non-P.H.S.
- Research Support, N.I.H., Extramural
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- 2 Finished
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MRSEC IRG-2: Sustainable Nanocrystal Materials
Kortshagen, U. R. (Coordinator), Aydil, E. S. (Senior Investigator), Campbell, S. A. (Senior Investigator), Francis, L. F. (Senior Investigator), Haynes, C. L. (Senior Investigator), Hogan, C. (Senior Investigator), Mkhoyan, A. (Senior Investigator), Shklovskii, B. I. (Senior Investigator) & Wang, X. (Senior Investigator)
11/1/14 → 10/31/20
Project: Research project
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