Electrochemical impedence spectroscopy enabled CA125 detection; toward early ovarian cancer diagnosis using graphene biosensors

With current diagnostic methods detection of stage 1 or 2 ovarian cancer using CA125 is possible in only 75% of cases. The ability to detect CA125 at lower concentrations could significantly improve such early stage diagnosis. Here, the use of screen-printed graphene biosensors as a label-free detection platform for CA125 was evaluated. The sensor was fabricated through deposition of a polyaniline layer via electropolymerisation on to a graphene screen-printed electrode. The sensor surface was functionalised with anti-CA125 antibody via covalent cross linking to polyaniline. The fabrication process was characterised through cyclic voltammetry and electrochemical impedance spectroscopy. The limit of detection achieved was 0.923 ng/μL across a dynamic range of 0.92 pg/μL–15.20 ng/μL and represents the most sensitive CA125 detection reported to date. With sensitivity limits at this level, it will now be possible to conduct clinical trials using serum samples collected from early stage ovarian cancer patients and at risk individuals.