Core-shell gold-silver nanoparticles based impedimetric immunosensor for cancer antigen CA125

We report a simple and fast assay for cancer antigen CA125 quantification using gold-silver core-shell nanoparticles for ovarian cancer diagnosis and prognosis. The impedimetric analysis of CA125 using label-free and reagentless immunosensor could be used done in 20 min. Furthermore, the directed immobilization of antibody onto the core-shell nanoparticles enabled linear response upto 1-150 IU/mL (r2 = 0.994) as opposed to the maximum linear response of 1.0-100.0 IU/mL reported for impedimetric immunosensors till date. The fabricated immunosensor displayed tolerable interference of 2.0-5% from serum components and retained 90% stability up to 20 days. Moreover, sensitivity of immunosensor fabricated using Au-Ag nanoparticles (190 Ω IU−1 mL cm−2) was almost three times that of gold nanoparticles based immunosensor (59 Ω U−1 mL cm−2).