Size And Shape Of Gold Nanoparticles Control The Interaction With Protein

Gold nanoparticles(AuNPs)have been extensively applied in biomedicine,information technology,environmental monitoring and other fields,due to their unique physical and chemical properties.AuNPs can enter living cells and induce a series of biological interactions,which attracted the interests of researchers.The results showed that these interactions are related to the size,shape,charge and surface medications of AuNPs,etc.Proteins are the most abundant components in cells.As the basis for supporting all life activities,proteins play important roles in regulating the physiological functions and maintaining the metabolism.The research on the interaction between spherical gold nanoparticles and proteins has been reported,and great advances have been made.However,there are few studies on the interaction between AuNPs with special shape and proteins.Consequently,it is particularly important to explore the mechanism of this interaction.The interaction of AuNPs for different sizes and shaps with the protein molecules of different types,(fibrinogen and trypsin)was studied by using ultraviolet-visible absorption(UV-vis)spectroscopy,fluorescence spectroscopy,dynamic light scattering(DLS)and transmission electron microscopy(TEM)techniques.The results demonstrate that the obvious aggregation of AuNPs were observed with the addition of fibrinogen and trypsin.The aggregation behavior of AuNPs induced by fibrinogen and trypsin was investigated with UV-vis absorption spectroscopy and DLS technique.It was found that the concentration of fibrinogen molecules has a great influence on the aggregation of spherical AuNPs in the lower concentration.For the same concentration of fibrinogen,the aggregation of the spherical AuNPs was dependent on their sizes.It is assumed that this phenomenon may be attributed to the unique chain structure of fibrinogen.The relationship between the protein corona and the size of the spherical AuNPs was evaluted using TEM,and the effects of the different sizes of spherical AuNPs on the secondary structure of fibrinogen and trypsin were analyzed by CD spectrum.In addition,we studied the interaction of the different shape AuNPs(rod-shaped and star-shaped)with fibrinogen and trypsin,and the results were compared to the interaction of spherical AuNPs with these two proteins.The results showed that protein corona was formed on the surface of AuNPs,and the obvious aggregation of AuNPs was found.Moreover,it can be seen that AuNPs have a significant quenching effects on fibrinogen and trypsin.Homogeneously,the interaction mechanism of AuNPs possessed different shape with fibrinogen and trypsin was estimated.The results suggested that the aggregation behavior of AuNPs with different size and shape induced by fibrinogen and trypsin were approximately similar.Due to the anisotropy of rod-shaped and star-shaped AuNPs,the precipitate phenomenon was not observed in the interaction of this two shape of AuNPs with fibrinogen and trypsin.In brief,this work will provide valuable reference for the further study on the nature of bio-nano interfaces and deep understanding the biological effects of nanoparticles.