Thermostability and reversibility of silver nanoparticle–protein binding

Abstract

The interactions between nanoparticles (NPs) and proteins in living systems are a precursor to the formation of a NP-protein "corona" that underlies cellular and organism responses to nanomaterials. However, the thermodynamic properties and reversibility of NP-protein interactions have rarely been examined. Using an automated, high-throughput and temperature-controlled dynamic light scattering (DLS) technique we observed a distinct hysteresis in the hydrodynamic radius of branched polyethyleneimine (BPEI) coated-silver nanoparticles (bAgNPs) exposed to like-charged lysozyme during the processes of heating and cooling, in contrast to the irreversible interactions between bAgNPs and oppositely charged alpha lactalbumin (ALact). Our discrete molecular dynamics (DMD) simulations offered a new molecular insight into the differential structure, dynamics and thermodynamics of bAgNPs binding with the two protein homologs and further revealed the different roles of the capping agents of citrate and BPEI in NP-protein interactions. This study facilitates our understanding of the transformation of nanomaterials in living systems, whose implications range from the field study of nanotoxicology to nanomaterials synthesis, nanobiotechnology and nanomedicine.

Cofibrillization of Pathogenic and Functional Amyloid Proteins with Gold Nanoparticles against Amyloidogenesis

“…21 According to prior analysis of bLg amyloid formation and its binding with AuNPs, 9, 22 the amyloid-forming segment 117 LACQCL 122 from the native bLg sequence was chosen to model the AuNP-binding bLg amyloids, as described in the SI. The sequence is one of the most amyloidogenic regions in the native bLg sequence according to the zipperDB server, which estimates the propensity of a given 6- or 7-residue sequence in forming the steric zipper cross-β conformation, 18, 23 and contains two cysteines with strong binding affinity for AuNPs.…”

Recent applications of light scattering measurement in the biological and biopharmaceutical sciences

“…The interaction between lysozyme and silver nanoparticles (NP) was studied by DLS and electron microscopy [41]. The hydrodynamic radii of isolated lysozyme and NP were independent of temperature up to 55°C.…”

Probing the modulated formation of gold nanoparticles–beta-lactoglobulin corona complexes and their applications

“…DMD simulations, a flavor of molecular dynamics algorithm with high computational sampling efficiency, have been successfully applied to study the nano-bio interface featuring large system sizes and high molecular complexities 29–30 . In DMD simulations, two major binding motifs driven by citrate-mediated electrostatic interactions were identified and the observed conformational changes of β-LG secondary structures were consistent with experimental characterizations.…”