Abstract
Diagnostics based on the determination of biomarkers in body fluids will be more successful when several biomarkers are determined. A multiple-array SPRi biosensor for the simultaneous determination of CA125, HE4, CEA, IL-6 and aromatase has been developed. Five individual biosensors were placed on the same chip. Each of them consisted of a suitable antibody covalently immobilized onto a gold chip surface via a cysteamine linker by means of the NHS/EDC protocol. The biosensor for IL-6 works in the pg mL-1 range, that for CA125 in the µg mL-1 range, and the other three within the ng mL-1 range; these are ranges suitable for the determination of biomarkers in real samples. The results obtained with the multiple-array biosensor are very similar to those obtained with a single biosensor. The applicability of the multiple biosensor was demonstrated using several examples of plasma from patients suffering from ovarian cancer and endometrial cyst. The average precision was 3.4% for the determination of CA125, 3.5% for HE4, 5.0% for CEA and IL-6, and 7.6% for aromatase. The simultaneous determination of several biomarkers may be an excellent tool for the screening of the population for earlier detection of diseases.