Abstracts Book - IMRC 2018

• SWMC-O021 Invited Talk
UNDERSTANDING THE INTRINSIC PROPERTIES OF
NANOCRYSTALS CONTROLLING THEIR ENVIRONMENTAL AND
BIOLOGICAL EFFECTS: THE CRITICAL ROLE OF EXPOSED FACETS
Tong Zhang 1 , Pedro Alvarez 2 , Wei Chen 1
1 Nankai University, College of Environmental Science and Engineering, China. 2 Rice University,
Department of Civil and Environmental Engineering, United States.
Responsible development of nanotechnology calls for improved understanding
of the effects of engineered nanomaterials on contaminant fate and transport
in the environment, as well as the interactions between nanomaterials with
biological receptors. Here, we reveal the critical roles of exposed facets of metalbased
nanomaterials in determining their reactivity towards organic
contaminants and biomolecules. First, we show that exposed facets of metal
oxide nanocrystals (e.g., nTiO 2 and nFe 2 O 3 ) can significantly affect the efficiency
of the nanomaterials in catalyzing environmentally relevant acid- and basecatalyzed
hydrolysis reactions, in that exposed facets affect both adsorption
affinities and concentrations of surface reactive moieties of nanocrystals and
consequently, result in facet-dependent catalytic efficiency. Second, we
challenge the common paradigm that higher nanomaterial reactivity leads to
higher cytotoxicity. We show that higher-surface-energy {001}-faceted CdS
nanorods are less toxic to the micro-organisms than lower-energy ({101}-
faceted) nanorods of similar morphology, surface charge and aggregate size,
due to its higher propensity to bind to the yeast’s cell wall, which decreased
endocytosis and cytotoxicity. Third, we show that the compositions of the
protein corona on the surface of crystalline nanomaterials are facet-dependent.
Nano-CdSe that contains higher content of the nonpolar facet {100}
preferentially adsorbs thiol-rich proteins and induces significant conformational
changes of these proteins.
Acknowledgment: This project was supported by the National Science Fund for
Distinguished Young Scholars (Grant 21425729), the Ministry of Science and
Technology of China (Grant 2014CB932001), and the National Natural Science
Foundation of China (Grants 21237002).
Keywords: nanocrystals, facets, contaminants
Presenting authors email: zhangtong@nankai.edu.cnc