Biomedical Engineering Reference
In-Depth Information
Fig. 6.8 Protective effects of metal chelators (a) and reactive oxygen species quenchers or
sucrose (b) on the survival of
E. coli
on copper surfaces. Cells were washed, mix with Cu
(II) chelator EDTA ((a),
gray bars
), Cu(I) chelator BCS ((a),
white bars
), ROS quenchers mannitol
((b)
horizontally striped bars
), catalase ((b),
dark gray bars
), superoxide dismutase ((b),
light gray
bars
) sucrose ((b),
white bars
), or no additive ((a, b),
black bars
), and applied on the metallic
copper surface. After 0, 45, and 60 s, samples were withdrawn and CFU were counted. Shown are
averages with standard deviations (
error bars
) from three independent experiments [
25
]
faster killing, and conversely, lower temperature corresponds to slower killing
(Fig.
6.9
)[
25
,
57
,
93
].
At the same time reversed correlation was observed between air moisture
content and killing rate with higher humidity of the air corresponding to the higher
survival rates on metallic copper [
23
,
57
].
6.3.2.3 Copper Chelators
As described before, copper is actively released from the surfaces and is either
dissolved in the buffer suspension or accumulated by the cells. Presence of chelators,
such as EDTA, increases the chance of survival on metallic copper surfaces (Fig.
6.8
)
[
25
,
86
]. Cell survival rates vary depending on the amount of chelator [
25
]. However,
it is noteworthy to mention that presence of chelators does not prevent cell death but
only delays it. Indeed, the released copper that has been chelated is no longer
available to cause toxic damage. However, more copper is released and copper-
saturated chelators are no longer available to avoid the toxic effects of free
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