Responsible development of nanotechnology calls for improved understanding of how the surface structure of nanomaterials affect their reactivity and the subsequent interactions with biological receptors and environmental media. Here, we reveal the critical roles of exposed facets of metal-based nanomaterials in determining their surface reactivity. First, we show the important role of exposed facets in the catalytic efficiency of nTiO2 for environmentally relevant hydrolysis reactions of organic contaminants. Through degradation and adsorption experiments, as well as theoretical calculations, we demonstrate that exposed facets significantly affect adsorption affinities and concentrations of surface reactive moieties of nTiO2 and consequently, result in facet-dependent catalytic efficiency. Second, we challenge the common paradigm that higher surface reactivity leads to greater 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 and surface charge, due to its higher propensity to bind to the yeast’s cell wall, which decreases endocytosis and cytotoxicity.

Exposed facets determine surface reactivity of metal-based nanomaterials towards environmental and biological receptors

255th National Meeting (2018)

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