Binding of polystyrene and carbon black nanoparticles to blood serum proteins

Abstract

Context: Once inhaled, nanoparticles (NP) deposit on the lung surface and have first contact with the epithelial lung lining fluid (ELF) rich in proteins, which may bind to NP.

Objective: In this study, we investigate the parameters that influence the binding between NP and proteins.

Materials and methods: We used the proteins albumin, transferrin (TF), and apolipoprotein A-1 (all known as proteins from ELF) and different NP (polystyrene NP with negative, positive, and neutral surface coatings, Printex G and Printex 90) as models.

Results: In all cases, a linear correlation of the added NP amount and the amount of bound proteins was found and was described quantitatively by binding indices. Bovine serum albumin (BSA), TF, and apo A-1 were bound to the largest extent to hydrophobic NP, which shows the extraordinary importance of the NP’s surface properties.

Discussion: The binding index indicates the relevance of primary particle size and surface properties, including hydrophobicity.

Conclusion: Size and surface modifications of NP determine their protein binding. Our results suggest that the formation of conjugates of BSA, TF, and Apo A-1 with NP may play an important role in their translocation across the air–blood–barrier and subsequent biokinetics.

Keywords::

• Nanoparticles
• Polystyrene
• Elemental carbon Printex
• Protein binding
• Bovine serum albumin
• Transferrin
• Apolipoprotein A1
• Binding index

Acknowledgments

We are grateful for the technical assistance of Carola Eggert and Franz Erbe.

Declaration of interest

This work was partially supported by the US-National Institutes of Health, NIH grant HL074022, by the German Research Foundation (DFG) grants FOR627 and SPP1313, by EU FP6 project Particle-Risk contract No. 012912 (NEST), and by EU FP7 project NeuroNano, NMP4-SL-2008–214547.