Gold nanoparticles modified screen-printed immunosensor for cancer biomarker HER2 determination based on anti HER2 bioconjugates

Human epidermal growth factor receptor 2 (HER2) is a biomarker of breast cancer plays a major role in the proliferation of breast cancer cells. The determination of HER2 concentration is one of the ways of early detection of breast cancer. In this study we have developed a label free immunosensor for the detection of HER2 using an anti HER2-gold nanoparticles (GNP) bioconjugates. Anti HER2-GNP bioconjugates synthesized by adding anti HER2 on the GNPs that already reacted with APTMS and PEG-NHS-Maleimide. GNP-APTMS characterized using FTIR and cyclic voltammetry with a potassium ferrisianide system. The anti HER2-GNP bioconjugates immobilized on the screen printed carbon electrode-GNP (SPCE-GNP) surface with covalent bonding systems (amine coupling). The result of this study showed FTIR spectra that anti HER2-GNP bioconjugates successfully synthesized. The cyclic voltammograms of GNP-SPCE without and with anti HER2-GNP bioconjugates showed the increase of fericyanide redox pair peak current from 51.946 µA to 121.891 µA. The anti HER2 bioconjugates binds HER2 then the fericyanide peak current decreases in proportion with the addition of HER2. Optimal response of current signal was generated at concentration 5.0 µg/mL anti HER2 and the incubation time of anti HER2-GNP was 1 hour. Limit of detection of HER2 from developed immunosensor is 1.02 x 10⁻² ng/mL.