Sensitive competitive label-free electrochemical immunosensor for primal detection of ovarian cancer

A simple, sensitive and one-step electrochemical technique was employed for the development of sandwich electrochemical immunosensor for the detection of CA 125 antigen. A unique three-dimensional gold nanostructure grown substrate is developed by electrodeposition technique to immobilize a large amount of anti-CA 125 through functionalization of gold nanostructures to immobilize cancer biomarker CA 125 and in human serum as well. The prepared immunosensor can directly amplify the electrochemical signal by making use of silicon nanoparticles conjugated with target antibody to achieve a detection limit of 1 pg ml(-1) in human serum. However, a comparative low detection limit of 1 fg ml(-1) with wide dynamic range from 1 mu g ml(-1) to 1 fg ml(-1) was obtained in cancer biomarker CA 125 solution. The immunosensor is sensitive, stable and reproducible in clinical serum samples. This gold nanostructures-based sandwich immunosensor can be mass manufactured, which may offer great potential to fabricate economical and sensitive immunosensor for broad applications in clinical diagnosis.