MEASURING THE DEGREE OF SURFACE MODIFICATION OF COLLOIDAL GOLD NANOPARTICLES USING ATOMIC FORCE MICROSCOPY
An approach for measuring the degree of surface modification of nanoparticles based on atomic force microscopy (AFM) is developed. The work was carried out for unmodified colloidal gold nanoparticles (GNP) and GNP coated by protein shell (GNP - immunoglobulin G conjugate). The proposed measurement of the degree of GNP surface modification is based on the registration of force curves, which reflect dependence of a tip deflection versus vertical movements of the cantilever. Elastic modulus and force of the interaction with surface of modified or unmodified nanoparticles are proposed as parameters characterizing the degree of nanoparticles modification. The application of AFM mode spectroscopy demonstrated significant differences between the unmodified and modified GNP.