Update (December 19, 2013): the article is now Open Access and has a functional DOI.

Update (December 1, 2013): we have submitted payment for Open Access publishing, and hope to have this processed as soon as possible. In the meantime, please find a free courtesy corrected proof available, hosted by chrisdieni.com. The DOI is still not yet functional, but the article is also available at the journal’s website via this link: http://www.scitechnol.com/spherical-gold-nanoparticles-impede-the-function-of-bovine-serum-albumin-in-vitro-a-new-consideration-for-studies-in-nanotoxicology-5suF.php?article_id=1506

Our recently-submitted manuscript, “Spherical gold nanoparticles impede the function of bovine serum albumin in vitro: a new consideration for studies in nanotoxicology” has just been accepted for publication by the Journal of Nanomaterials and Molecular Nanotechology.

The study, spearheaded by Tyson MacCormack and his honours students in the summer of 2011, focuses on the investigation of an abundant blood plasma protein, serum albumin (specifically the bovine variant), and the effect of its interactions with spherical gold nanoparticles on its ability to bind various ligands. The effect of nanoparticle diameter (size), and nanoparticle functionalization (small citrate-like proprietary capping agent, carboxyl functionalization, amine functionalization) are systematically investigated.

We hope to have a DOI available for sharing in the very near future.

Dieni CA, Stone CJL, Armstrong ML, Callaghan NI, MacCormack TJ (2013) Spherical gold nanoparticles impede the function of bovine serum albumin in vitro: a new consideration for studies in nanotoxicology. J Nanomater Mol Nanotechnol in press.

Suspensions of bovine serum albumin (BSA) and spherical gold nanoparticles were analyzed to determine if gold nanoparticles (nAu) affect the ligand binding properties of BSA. A range of diameters of nAu with a carboxylic acid capping agent (nAu-cap) were tested, along with nanoparticles conjugated to amine (nAu-NH3+) and carboxyl (nAu-COO) functional groups via a covalent polymer bridge. All nAu tested were found to affect BSA conformation as determined by intrinsic tryptophan fluorescence. Smaller diameters of nAu-cap (30-50 nm), along with nAu-NH3+ and nAu-COO, impeded the binding of 8-anilino-1-napthalenesulfonic acid (ANS) to BSA. Similarly, smaller diameters of nAu-cap tended to impede oleic acid binding to BSA, with a linear negative correlation observed between nAu-cap diameter and the dissociation constant (KD) of oleic acid over the range of 40-80 nm. 80 nm nAu-cap impeded butanoic acid binding, and necessitated a high-resolution fluorescence assay. As with oleic acid, smaller diameters of nAu-cap tended to impede ibuprofen binding, but no significance could be established. nAu-NH3+ and nAu-COO reduced the binding of thyroxine and bilirubin to BSA, with nAu-COO having a more pronounced effect in both cases. Visible-light spectral scans determined that interactions between BSA and different sizes of nAu did not change significantly over the course of 1 week, as established by relatively stable wavelengths of maximum absorbance. In order to isolate strongly-interacting BSA oligomers, irreversible BSA aggregates, or strong BSA-nAu complexes induced by recruitment of BSA into the protein corona, BSA-nAu-cap suspensions were subjected to centrifugal filtration and native-PAGE, however, this methodology failed to detect any altered distribution of higher-molecular weight species of BSA compared to control (free of nAu), suggesting that any protein-protein or protein-nAu interactions that contribute to these altered properties of BSA are not irreversible and do not withstand high g-forces and/or electrophoresis.

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