Immobilization of gamma globulins and polyclonal antibodies of class IgG onto carbon-encapsulated iron nanoparticles functionalized with various surface linkers

The immobilization of gamma-globulins from human and bovine blood and human polyclonal antibody (IgG) onto carbon-encapsulated iron nanoparticles (CEINs) is reported. First, the CEINs were functionalized to introduce the surface acidic linkers with a different length. The shorter linker was introduced by a typical oxidation treatment in concentrated acids. The longer linker was anchored by a free radical addition route, in which the radicals were generated by the thermal decomposition of succinic acid acyl peroxide. Both functionalization routes caused a partial perforation of the carbon coating. This structural degradation was determined quantitatively by evaluation the Fe content in the functionalized CEINs. Gamma-globulins and human polyclonal antibody (IgG) were immobilized onto the linker-functionalized surface using the carbodiimide-amine type reaction. The success of immobilization was confirmed by infrared spectroscopy, thermogravimetry and protein assay, respectively. The immune reactivity of the immobilized primary human polyclonal antibody (IgG) was also confirmed in a reaction with a FITC-labeled goat secondary antibody (anti-IgG) recognizing the primary human antibody in CEINs. It has been found that the immobilization yield is primarily dependent on the length of the acidic linker, whilst the content of carboxylic groups is of secondary importance.