Background
Human biodistribution, bioprocessing and possible toxicity of nanoscale silver receives increasing health assessment.
Methods
We prospectively studied commercial 10- and 32-ppm nanoscale silver particle solutions in a single-blind, controlled, cross-over, intent-to-treat, design. Healthy subjects (n=60) underwent metabolic, blood counts, urinalysis, sputum induction, and chest and abdomen magnetic resonance imaging. Silver serum and urine content was determined.
Results
No clinically important changes in metabolic, hematologic, or urinalysis measures were identified. No morphological changes were detected in the lungs, heart or abdominal organs. No significant changes were noted in pulmonary reactive oxygen species or pro-inflammatory cytokine generation.
Conclusion
In vivo oral exposure to these commercial nanoscale silver particle solutions does not prompt clinically important changes in human metabolic, hematologic, urine, physical findings or imaging morphology. Further study of increasing time exposure and dosing of silver nanoparticulate silver, and observation of additional organ systems is warranted to assert human toxicity thresholds.
Two Cu(II) metal–organic frameworks
(MOFs) were prepared
on the nanoscale at room temperature using a microemulsion method,
namely, [Cu3(BTC)2(H2O)3] (BTC = benzene-1,3,5-tricarboxylate), known as HKUST-1 (1), and [Cu2(OH)(BTC)(H2O)]·2H2O (2). Thermochemical and gas sorption properties of
the microporous topologies were characterized by mid- and far-infrared
vibrational spectroscopy, supported by periodic density functional
theory calculations. The mid-infrared profile of 1 appeared
altered in response to gas sorption under variable temperature and
pressure conditions. Vibrational mode analysis indicated the most
sensitive infrared peaks were associated with the internal vibrations
of organic linker moieties indirectly coupled to the Cu(II)–gas
coordination site, activated by a lowered symmetry induced by guest
interactions. Synchrotron far-infrared spectroscopy was shown to be
a useful diagnostic for the microstructure of 1 and 2 where different temperature dependences were displayed in
the low-frequency region. The loss of residual water during the activation
of 2 at elevated temperature coincides with peaks indicative
of free paddle-wheel moieties emerging in the far-IR spectra. As demonstrated
for both materials 1 and 2, vibrational
mode analysis was effective in screening MOF materials for their propensity
toward gas uptake and, inversely, the diffusion of guest species such
as adsorbed water from the microporous environments.
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