Abstract
Metal nanoparticles (NPs) scatter and absorb light in precise, designable ways, making them agile candidates for a variety of biomedical applications. When NPs are introduced to a physiological environment and interact with cells, their physicochemical properties can change as proteins adsorb on their surface and they agglomerate within intracellular endosomal vesicles. Since the plasmonic properties of metal NPs are dependent on their geometry and local environment, these physicochemical changes may alter the NPs' plasmonic properties, on which applications such as plasmonic photothermal therapy and photonic gene circuits are based. Here we systematically study and quantify how metal NPs' optical spectra change upon introduction to a cellular environment in which NPs agglomerate within endosomal vesicles. Using darkfield hyperspectral imaging, we measure changes in the peak wavelength, broadening, and distribution of 100-nm spherical gold NPs' optical spectra following introduction to human breast adenocarcinoma Sk-Br-3 cells as a function of NP exposure dose and time. On a cellular level, spectra shift up to 78.6 ± 23.5 nm after 24 h of NP exposure. Importantly, spectra broaden with time, achieving a spectral width of 105.9 ± 11.7 nm at 95% of the spectrum's maximum intensity after 24 h. On an individual intracellular NP cluster (NPC) level, spectra also show significant shifting, broadening, and heterogeneity after 24 h. Cellular transmission electron microscopy (TEM) and electromagnetic simulations of NPCs support the trends in spectral changes we measured. These quantitative data can help guide the design of metal NPs introduced to cellular environments in plasmonic NP-mediated biomedical technologies.
Original language | English (US) |
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Article number | 454 |
Journal | Nanoscale Research Letters |
Volume | 9 |
Issue number | 1 |
DOIs | |
State | Published - 2014 |
Funding
This work was supported in part by the Robert A. Welch Foundation (C-1598). A. Chen gratefully acknowledges support from the National Science Foundation through a Graduate Research Fellowship (0940902) and from the Keck Center of the Gulf Coast Consortia through the Nanobiology Interdisciplinary Graduate Training Program (NIH Grant No. T32EB009379). A. Lin acknowledges support from the Medical Scientist Training Program at Baylor College of Medicine, the Edward and Josephine Hudson Scholarship, and the Ruth L. Kirschstein National Research Service Awards for Individual Predoctoral MD/PhD Fellows (5F30CA165686) by NIH and NCI. We thank K. Dunner, Jr. of The University of Texas M.D. Anderson Cancer Center High Resolution Electron Microscopy Facility (Institutional Core Grant No. CA16672) for TEM sample processing and imaging services, and thank A. Coughlin, J. Almeida, E. Figueroa, V. Asthana, A. Hoggard, S. Link, and E. Reiser for thoughtful discussions.
Keywords
- Cells
- Gold nanoparticles
- Hyperspectral imaging
- Nano-bio interactions
- Nanomedicine
- Plasmon resonance
- Spectral analysis
ASJC Scopus subject areas
- Condensed Matter Physics
- General Materials Science