Oriented Immobilization of Anti-IgG on Amine Functionalized Carbon Nanotubes for Electrochemical Sensing of Human IgG

The oriented immobilization of antibody is the most critical step in preparation of ahighly sensitive immunosensor. in the present report multiwalled carbon nanotubes weretreated with nitric acid followed by ethylenediamine to produce amine functionalized carbonnanotubes. to obtain a properly oriented immobilization, initially the sugar chain of antibody(anti-igg) was oxidized to aldehyde using periodate and then the aldehyde groups wereallowed to react with amine groups of carbon nanotubes. the antibody immobilization wasverified using the techniques such as field emission scanning electron microscope, fouriertransform infrared, uv-vis spectroscopy and electrochemistry. finally determination ofantigen (human igg) was performed in the presence of conjugated horseradish peroxidase asa label, and h2o2 and potassium iodide as the enzyme substrates. at the optimum ph of 7.2,the detection limit of 16.6 ng/ml was obtained for determination of human igg.