Much more than average, single-cell analysis reveals heterogeneity in
metal adsorption
Date:
March 22, 2022
Source:
University of Tsukuba
Summary:
A research team has reported an in-depth analysis of precious
metal adsorption onto Galdieria sulphuraria algae. The combination
of X-ray absorption fine structure spectroscopy and single-cell
inductively coupled plasma mass spectrometry allowed the cell
population behavior to be related to chemical interactions that
occurred between the metals and the cell surface. The insight
is expected to contribute to the development of environmentally
friendly cell-derived approaches for metal recycling and wastewater
treatment.
FULL STORY ========================================================================== Biosorption is the removal of contaminants from a sample by adsorbing
them onto the surface of a biological material. It is expected to
provide environmental and economic benefits compared with conventional separation techniques. A team of scientists including a researcher
from the University of Tsukuba has analyzed the interaction of
Galdieria sulphuraria algae with precious metals to better understand
the biosorption process. Their findings are published inJournal of
Hazardous Materials.
========================================================================== Precious metals -- including gold, platinum, and palladium -- have been detected in the environment at trace levels and the associated health
and ecological risks are not well understood. Removing these metals using standard approaches can be challenging because other contaminant elements
with generally higher concentrations -- iron and copper, for example --
provide competition.
Biosorption is a potential alternative that could also present financial benefits through recycling of the expensive elements. Understanding and optimizing the biosorption of precious metals is therefore an important research area.
Massive datasets that consider both the sorption efficiency and capacity
of the biomaterials have been accumulated. However, so far, the findings
have been averaged over the entire cell population and it has not been
possible to assess adsorption at the single-cell level.
Now, the team has combined X-ray absorption fine structure (XAFS)
spectroscopy -- which has been used to analyze the way metals adsorb onto
cells -- with single-cell inductively couple plasma mass spectrometry (scICP-MS) to provide the link between the behavior of the cell population
and the nature of the interactions between the metals and the cells at
the cell surface.
"Combining XAFS and scICP-MS, and using low metal concentrations,
meant that we could get a really close look at the specific interactions
taking place at the cell surface," explains lead author Professor Ayumi
Minoda. "We found that the amount of metal adsorbed depended on the metal
in question and the acidity of the solution." In low acidity conditions
gold, platinum, and palladium all adsorbed to the cells. The gold was
found to interact with sulfur containing groups at the cell surface,
whereas platinum and palladium interacted with both sulfur and nitrogen containing groups.
Interestingly, at high acidity, only gold and palladium adsorbed onto
the cells and only through interaction with sulfur. The distribution
pattern of the palladium-adsorbing cells -- both the number of cells
that adsorbed palladium and the amount of palladium adsorbed -- changed drastically. This is the first report to link such interactions to
changes in the behavior of the cell population and clearly demonstrates
a differential adsorption mechanism under different environmental
conditions.
"The insight achieved is expected to contribute to future engineering
of cell surfaces to provide enhanced metal adsorption," says Professor
Minoda.
"Optimizing the performance of biologically-derived precious metal
adsorbents is expected to significantly improve the environmental sustainability of metal recycling and remediation."
========================================================================== Story Source: Materials provided by University_of_Tsukuba. Note: Content
may be edited for style and length.
========================================================================== Journal Reference:
1. Ayumi Minoda, Shin-ichi Miyashita, Shin-ichiro Fujii, Kazumi
Inagaki,
Yoshio Takahashi. Cell population behavior of the unicellular
red alga Galdieria sulphuraria during precious metal
biosorption. Journal of Hazardous Materials, 2022; 432: 128576 DOI:
10.1016/j.jhazmat.2022.128576 ==========================================================================
Link to news story:
https://www.sciencedaily.com/releases/2022/03/220322111328.htm
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