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Title: Liquid Surface X-ray Studies of Gold Nanoparticle–Phospholipid Films at the Air/Water Interface

Authors:
; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
National Science Foundation (NSF)
OSTI Identifier:
1346217
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry; Journal Volume: 120; Journal Issue: 34
Country of Publication:
United States
Language:
ENGLISH

Citation Formats

You, Siheng Sean, Heffern, Charles T. R., Dai, Yeling, Meron, Mati, Henderson, J. Michael, Bu, Wei, Xie, Wenyi, Lee, Ka Yee C., and Lin, Binhua. Liquid Surface X-ray Studies of Gold Nanoparticle–Phospholipid Films at the Air/Water Interface. United States: N. p., 2016. Web. doi:10.1021/acs.jpcb.6b03734.
You, Siheng Sean, Heffern, Charles T. R., Dai, Yeling, Meron, Mati, Henderson, J. Michael, Bu, Wei, Xie, Wenyi, Lee, Ka Yee C., & Lin, Binhua. Liquid Surface X-ray Studies of Gold Nanoparticle–Phospholipid Films at the Air/Water Interface. United States. doi:10.1021/acs.jpcb.6b03734.
You, Siheng Sean, Heffern, Charles T. R., Dai, Yeling, Meron, Mati, Henderson, J. Michael, Bu, Wei, Xie, Wenyi, Lee, Ka Yee C., and Lin, Binhua. Thu . "Liquid Surface X-ray Studies of Gold Nanoparticle–Phospholipid Films at the Air/Water Interface". United States. doi:10.1021/acs.jpcb.6b03734.
@article{osti_1346217,
title = {Liquid Surface X-ray Studies of Gold Nanoparticle–Phospholipid Films at the Air/Water Interface},
author = {You, Siheng Sean and Heffern, Charles T. R. and Dai, Yeling and Meron, Mati and Henderson, J. Michael and Bu, Wei and Xie, Wenyi and Lee, Ka Yee C. and Lin, Binhua},
abstractNote = {},
doi = {10.1021/acs.jpcb.6b03734},
journal = {Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry},
number = 34,
volume = 120,
place = {United States},
year = {Thu Sep 01 00:00:00 EDT 2016},
month = {Thu Sep 01 00:00:00 EDT 2016}
}
  • No abstract prepared.
  • Here, massive amounts of organic carbon have accumulated in Arctic permafrost and soils due to anoxic and low temperature conditions that limit aerobic microbial respiration. Alternative electron acceptors are thus required for microbes to degrade organic carbon in these soils. Iron or iron oxides have been recognized to play an important role in carbon cycle processes in Arctic soils, although the exact form and role as an electron acceptor or donor remain poorly understood. Here, Arctic biofilms collected during the summers of 2016 and 2017 from tundra surface waters on the Seward Peninsula of western Alaska were characterized with amore » suite of microscopic and spectroscopic methods. We hypothesized that these films contain redox-active minerals bound to biological polymers. The major components of the films were found to be iron oxide nanoparticle aggregates associated with extracellular polymeric substances. The observed mineral phases varied between films collected in different years with magnetite (Fe 2+Fe 2 3+O 4) nanoparticles (<5 nm) predominantly identified in the 2016 films, while for films collected in 2017 ferrihydrite-like amorphous iron oxyhydroxides were found. While the exact formation mechanism of these Artic iron oxide films remains to be explored, the presence of magnetite and other iron oxide/oxyhydroxide nanoparticles at the air–water interface may represent a previously unknown source of electron acceptors for continual anaerobic microbial respiration of organic carbon within poorly drained Arctic tundra.« less
  • Purpose: There have been several reports of enhanced cell-killing and tumor regression when tumor cells and mouse tumors were loaded with gold nanoparticles (GNPs) prior to proton irradiation. While particle-induced xray emission (PIXE), Auger electrons, secondary electrons, free radicals, and biological effects have been suggested as potential mechanisms responsible for the observed GNP-mediated dose enhancement/radiosensitization, there is a lack of quantitative analysis regarding the contribution from each mechanism. Here, we report our experimental effort to quantify some of these effects. Methods: 5-cm-long cylindrical plastic vials were filled with 1.8 mL of either water or water mixed with cylindrical GNPs atmore » the same gold concentration (0.3 mg Au/g) as used in previous animal studies. A piece of EBT2 radiochromic film (30-µm active-layer sandwiched between 80/175-µm outer-layers) was inserted along the long axis of each vial and used to measure dose enhancement due to PIXE from GNPs. Vials were placed at center-of-modulation (COM) and 3-cm up-/down-stream from COM and irradiated with 5 different doses (2–10 Gy) using 10-cm-SOBP 160-MeV protons. After irradiation, films were cleaned and read to determine the delivered dose. A vial containing spherical GNPs (20 mg Au/g) was also irradiated, and gamma-rays from activation products were measured using a cadmium-telluride (CdTe) detector. Results: Film measurements showed no significant dose enhancement beyond the experimental uncertainty (∼2%). There was a detectable activation product from GNPs, but it appeared to contribute to dose enhancement minimally (<0.01%). Conclusion: Considering the composition of EBT2 film, it can be inferred that gold characteristic x-rays from PIXE and their secondary electrons make insignificant contribution to dose enhancement. The current investigation also suggests negligible dose enhancement due to activation products. Thus, previously-reported GNP-mediated proton dose enhancement/radiosensitization needs to be attributed to one or more of the other mechanisms listed earlier. Supported in part by NIH/NCI grant R01CA155446;This investigation was supported in part by NIH/NCI grant R01CA155446.« less
  • No abstract prepared.