Polystyrene Nanoplastic Contaminants Denature Human Apolipoprotein A-1

The subject of nanoplastics is of growing importance, as the use of plastics in our everyday lives has caused nanoplastics to be abundant in the air, water, and soil, bringing them in contact with humans and animals. Understanding how proteins bind and structure themselves at these nanoplastic interfaces is critical for determining the toxicity and health implications of nanoplastics. Proteomics has determined the most abundant protein in human protein corona formed around nanoplastics; however, the structure and orientation of these proteins is extremely challenging to determine. We use <i>in situ</i> sum frequency scattering vibrational spectroscopy and two-dimensional infrared spectroscopy to probe the structure of human liver protein apolipoprotein A-1 (ApoA-1) when adsorbed to polystyrene (PS) nanoparticles. The spectra indicate that ApoA-1 aggregates and forms fibrillar structures at the PS nanoplastic interface, leading to clustering of PS nanoplastics, which may pose a significant risk to human health.