Probing protein dissociation from gold nanoparticles and the influence of temperature from the protein corona formation mechanism

Gold nanoparticles (AuNPs) provide a novel approach for protein enrichment and analysis due to their protein adsorption properties, forming a so called protein corona. This corona can significantly influence the protein's structure and characteristics, hindering their identification in situ. Dissociation is an important solution to analyze and identify the composition of protein coronas. However, a comprehensive picture of adsorbed protein dissociation is lacking. In this study, the protein dissociation from the protein corona and influencing factors were investigated on the basis of the formation mechanism and time evolution. Temperature and cysteine are the key factors influencing protein dissociation by altering the protein's binding ability. The results showed that half Au–S formation time is an important time point for thio-protein dissociation by the method of high speed centrifugation. When incubated for longer than that time, the thio-protein located in the hard corona could only be separated by β-mercaptoethanol replacement under analytical ultracentrifugation. However, Fourier-transform infrared spectroscopy (FTIR) revealed significant changes that occurred in βlg's secondary structure after ultracentrifugation. The Au–S bond formation time offers the potential to define the protein enrichment time of AuNPs.