Quantum dots (QDs) hold increasing applications to solar panels, consumer electronics, and biomedical imaging. For biomedical applications, QDs are typically coated with a biocompatible molecule for the system of interest. Yet even with a surface coating, experiments have indicated a QD dose-dependent and surface coating-dependent toxicity, with a portion of toxicity being ascribed to interference with biomolecules. In this work, we explore the interaction of trioctylphosphine oxide (TOPO) coated (CdSe)<sub>13</sub> QDs with the SH3 protein signaling domain using Molecular Dynamics simulations. We compute binding free energy surfaces and distinguish concentration dependent behavior of QD binding. Our results agree well with experiment that at the lowest concentration, the QDs have little affinity for the native PRM binding site of SH3. At higher concentrations, the QDs aggregate and increasingly target the PRM binding site, indicating impedance of normal SH3 function. This binding dependence is attributed to changes in local density of surface coated TOPO molecules upon aggregation. Our results present interesting possible QD toxicity patterns and reveal the interdependence between dose and surface coating effects in QD toxicity.<br/>

Concentration-dependent binding behavior of CdSe quantum dot on SH3 domain

256th National Meeting (2018)

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