C₆₀ Bioconjugation with Proteins: Towards a Palette of Carriers for All pH Ranges

Abstract

The high hydrophobicity of fullerenes and the resulting formation of aggregates in aqueous solutions hamper the possibility of their exploitation in many technological applications. Noncovalent bioconjugation of fullerenes with proteins is an emerging approach for their dispersion in aqueous media. Contrary to covalent functionalization, bioconjugation preserves the physicochemical properties of the carbon nanostructure. The unique photophysical and photochemical properties of fullerenes are then fully accessible for applications in nanomedicine, sensoristic, biocatalysis and materials science fields. And yet, proteins are not universal carriers. Their stability depends on the biological conditions for which they have evolved. Here we present two model systems based on pepsin and trypsin. These proteins have opposite net charge at physiological pH. They recognize and disperse C60 in water. UV-Vis spectroscopy, zeta-potential and atomic force microscopy analysis demonstrates that the hybrids are well dispersed and stable in a wide range of pH’s and ionic strengths. A previously validated modelling approach identifies the protein binding pocket involved in the interaction with C60. Computational predictions, combined with experimental investigations, provide powerful tools to design tailor-made C60@proteins bioconjugates for specific applications.

Investigating the Size-Dependent Binding of Pristine nC60 to Bovine Serum Albumin by Multi-Spectroscopic Techniques

“…Previous studies have shown that nC 60 and its derivatives can bind to a variety of proteins (peptides) and change their conformation and structure, and the morphological characteristics of nC 60 and its derivatives have a certain effect on these bindings [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ]. Since unmodified nC 60 is not soluble in water, most of the studies were on water-soluble nC 60 derivatives.…”