Probing the Aggregation Mechanism of Gold Nanoparticles Triggered by a Globular Protein

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• 作者：Sunanda Neupane ; Yanxiong Pan ; Sunitha Takalkar ; Kylie Bentz ; Jasmin Farmakes ; Yi Xu ; Bingcan Chen ; Guodong Liu ; Steven Y. Qian ; Zhongyu Yang
• 刊名：Journal of Physical Chemistry C
• 出版年：2017
• 出版时间：January 19, 2017
• 年：2017
• 卷：121
• 期：2
• 页码：1377-1386
• 全文大小：560K
• ISSN：1932-7455

文摘

Gold nanoparticles (AuNPs) are advancing a number of areas. Meanwhile, the inevitable contact of AuNPs with surrounding biomolecules has been realized to “negatively” impact the nanoparticle (NP) function, biological environment, and even public health. Understanding the mechanisms of the NP–biomolecule interaction often leads to revealing the pathways toward the negative, deleterious effects. It is therefore essential to know the undesirable pathways so that these unwanted effects can be reduced by blocking or rerouting these pathways. A fundamental step to understand the interaction mechanism is to elucidate the changes in protein structure and dynamics and in NP properties upon the contact of AuNPs and protein, at the molecular level. However, it is challenging to probe these areas experimentally due to the large size and the complexity of the protein–nano interface. Here we report the use of a unique approach, electron paramagnetic resonance (EPR) spectroscopy, to probe the structure and dynamics of a model protein, T4 lysozyme (T4L), upon interaction with AuNPs. In combination with circular dichroism (CD) spectroscopy, UV–vis spectroscopy, and a protein activity assay, we found that T4L triggered the AuNPs to aggregate but remained in its native structure. Remarkably, our results also revealed the pathways of how T4L triggers AuNP aggregation, the potential applications of which were discussed. Lastly, this work demonstrated the usefulness of the EPR spectroscopy in probing the complexes formed by nanomaterials and macrobiomolecules, opening a new window to probe the nano–bio interface in the native state.