Understanding the protein corona on engineered nanoparticles used in food products

Abstract

Engineered nanomaterials (ENMs) such as silicon dioxide (SiO2) and titanium dioxide (TiO2) nanoparticles have been commonly used in food applications for decades owing to their ability to enhance food characteristics, production and shelf-life. When humans are exposed to or ingested these nanoparticles, protein corona is formed between the nanoparticles and surrounding biological media in our body. Consequently, nanoparticles own a new biological identity due to protein corona formation. It has garnered much attention lately that the cellular uptake and toxicity of nanoparticles could be altered when proteins are adsorbed onto the nanoparticle surface. As the fate of ENMs in the biological system changes, it is essential to appreciate the risks of engineered nanoparticles in food products. Herein, this project aims to understand the effects of varying protein concentrations and incubation times on protein corona formation. In addition, it investigates the least incubation time at which MALDI-ToF MS could identify the proteins. Food grade SiO2 (E551) and food grade TiO2 (E171) nanoparticles were suspended in model protein Bovine Serum Albumin (BSA) solutions of varying protein concentrations and incubation times to evaluate the affinity and adsorption capability of proteins to each nanoparticle type. Analytical tools which include Matrix Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-ToF MS), micro Bicinchoninic Acid (BCA) Protein Assay Kit, Thermal Gravimetric Analysis (TGA) and Fourier Transform Infrared (FTIR) spectroscopy were used to evaluate the amount and identity of the protein corona. From the results, both nanoparticles displayed a higher amount of protein corona when the protein concentration and incubation time were increased which could be explained by the Vroman effect. Interestingly, the protein corona could be identified after a short period of incubation time, which highly suggests the rapid and dynamic process of protein corona formation on the nanoparticle surface. It was noted from the incubation time point study that the adsorption of proteins onto both nanoparticle surfaces could have reached equilibrium after 24 hours. Overall, different nanoparticles exhibit different abilities to adsorb the proteins as more protein corona was formed in SiO2-BSA samples in comparison to TiO2-BSA samples. These findings are useful to examine and gain a deeper understanding of how varying protein concentration and incubation time affects the protein corona formation on engineered nanoparticles from food products.