es300514s_si_001.pdf (866.73 kB)
Impact of Surface Functionalization on Bacterial Cytotoxicity of Single-Walled Carbon Nanotubes
journal contribution
posted on 2012-06-05, 00:00 authored by Leanne
M. Pasquini, Sara M. Hashmi, Toby J. Sommer, Menachem Elimelech, Julie B. ZimmermanThe addition of surface functional groups to single-walled
carbon
nanotubes (SWNTs) is realized as an opportunity to achieve enhanced
functionality in the intended application. At the same time, several
functionalized SWNTs (fSWNTs), compared to SWNTs, have been shown
to exhibit decreased cytotoxicity. Therefore, this unique class of
emerging nanomaterials offers the potential enhancement of SWNT applications
and potentially simultaneous reduction of their negative human health
and environmental impacts depending on the specific functionalization.
Here, the percent cell viability loss of Escherichia coli K12 resulting from the interaction with nine fSWNTs, n-propylamine, phenylhydrazine, hydroxyl, phenydicarboxy, phenyl,
sulfonic acid, n-butyl, diphenylcyclopropyl, and
hydrazine SWNT, is presented. The functional groups range in molecular
size, chemical composition, and physicochemical properties. While
physiochemical characteristics of the fSWNTs did not correlate, either
singularly or in combination, with the observed trend in cell viability,
results from combined light scattering techniques (both dynamic and
static) elucidate that the percent loss of cell viability can be correlated
to fSWNT aggregate size distribution, or dispersity, as well as morphology.
Specifically, when the aggregate size polydispersity, quantified as
the width of the distribution curve, and the aggregate compactness,
quantified by the fractal dimension, are taken together, we find that
highly compact and narrowly distributed aggregate size are characteristics
of fSWNTs that result in reduced cytotoxicity. The results presented
here suggest that surface functionalization has an indirect effect
on the bacterial cytotoxicity of SWNTs through the impact on aggregation
state, both dispersity and morphology.