A disposable and ultrasensitive immunosensor for the detection of HE4 in human serum samples

Ovarian cancer is described as excessive cell proliferation in the ovaries. It is thought that ovarian cancer and the human epididymis protein 4 (HE4) are closely linked. HE4 is approved as a critical biomarker for the diagnosis and the progression monitoring of the ovarian cancer. In this work, an impedimetric biosensor was fabricated for the analysis of HE4 by modifying the surface of disposable ITO-PET (indium tin oxide-polyethylene terephthalate) sheet with a certain dimensions by 3-Aminopropyl trimethoxy silane (3-APTES). For the interaction between the amino ends of 3-APTES and anti-HE4 antibodies glutaraldehyde was used as a cross-linker. Electrochemical impedance (EIS) and cyclic voltammetry (CV) methods were applied in all electrochemical measurements. Important optimization and characterization experiments have also been completed. Under the optimum conditions, the concentration range for HE4 was obtained between 1 pg/mL and 3000 pg/mL with an LOD and LOQ values of 0.094 pg/mL and 0.3134 pg/mL, respectively. Selectivity experiments revealed that the biosensor showed a great selectivity with its target HE4. The biosensor also showed a good reproducibility with a relative standard deviation (RSD) of slope data calculated as 2.443%. Finally, we applied the biosensor to the commercial real human serum samples for analysis of HE4 and the results of these experiments were encouraging to be used in clinical settings.