Charge-transfer interactions induce surface dependent conformational changes in apolipoprotein biocorona.

Area of Science:

• Nanotoxicology
• Biomaterials Science
• Protein-Nanomaterial Interactions

Background:

• Engineered nanomaterials (ENMs) interact with biological systems by forming a biomolecular layer known as a biocorona.
• The biocorona significantly influences nanoparticle behavior and biological outcomes.
• Apolipoprotein A-I (ApoA-I), a key component of high-density lipoprotein (HDL), is frequently found in ENM biocoronas.

Purpose of the Study:

• To investigate the adsorption mechanisms and structural alterations of ApoA-I on silver nanoparticles (AgNPs) with varying surface functionalities.
• To understand how surface chemistry influences ApoA-I interactions and subsequent biological effects.
• To elucidate the role of charge transfer in ApoA-I unfolding on nanomaterials.

Main Methods:

• Utilized a combination of microscopic and spectroscopic techniques to study ApoA-I interactions with 100 nm AgNPs.
• Employed electrochemical methods to probe charge transfer interactions.
• Assessed nanoparticle uptake, short-term cytotoxicity, and reactive oxygen species (ROS) generation.

Main Results:

• Protein adsorption and secondary structural changes of ApoA-I were found to be highly dependent on the AgNP surface functionality.
• Electrochemical studies revealed charge transfer interactions contributing to ApoA-I unfolding.
• ApoA-I unfolding did not significantly impact AgNP uptake or short-term cytotoxicity but altered ROS generation in a surface-dependent manner.

Conclusions:

• The surface functionality of ENMs critically dictates ApoA-I adsorption and structural changes.
• Charge transfer interactions play a significant role in the modulation of ApoA-I structure upon binding to nanomaterials.
• Understanding these surface-driven biocorona formation mechanisms is crucial for predicting the biological consequences of ENM exposure.