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Facet Energy and Reactivity versus Cytotoxicity: The Surprising Behavior of CdS Nanorods
journal contribution
posted on 2016-01-13, 00:00 authored by Lu Liu, Meiqing Sun, Haijun Zhang, Qilin Yu, Mingchun Li, Yu Qi, Chengdong Zhang, Guandao Gao, Yingjin Yuan, Huanhuan Zhai, Wei Chen, Pedro J. J. AlvarezResponsible development of nanotechnology
calls for improved understanding of how nanomaterial surface energy
and reactivity affect potential toxicity. Here, we challenge the paradigm
that cytotoxicity increases with nanoparticle reactivity. Higher-surface-energy
{001}-faceted CdS nanorods (CdS-H) were less toxic to Saccharomyces
cerevisiae than lower-energy ({101}-faceted) nanorods (CdS-L)
of similar morphology, aggregate size, and charge. CdS-H adsorbed
to the yeast’s cell wall to a greater extent than CdS-L, which
decreased endocytosis and cytotoxicity. Higher uptake of CdS-L decreased
cell viability and increased endoplasmatic reticulum stress despite
lower release of toxic Cd2+ ions. Higher toxicity of CdS-L
was confirmed with five different unicellular microorganisms. Overall,
higher-energy nanocrystals may exhibit greater propensity to adsorb
to or react with biological protective barriers and/or background
constituents, which passivates their reactivity and reduces their
bioavailability and cytotoxicity.