Développement de nouveaux biocapteurs électrochimiques pour la détection spécifique de biomarqueurs du cancer de la prostate

Prostate cancer is the fifth most lethal cancer in the world. Better management through early diagnosis could significantly reduce mortality. In the absence of a 100% specific biomarker, the use of different tumour biomarkers would significantly improve the specificity and selectivity of the test and therefore a better detection of prostate cancer. In this context, three electrochemical biosensors were designed for the detection of different prostate cancer biomarkers: prostate-specific antigen (PSA), Engrailed 2 (EN2) and prostate cancer gene 3 (PCA3). The first biosensor: functionalized with molecularly imprinted polymers, was dedicated to the selective detection of PSA. Electrochemical studies showed a high affinity between the analytes and the imprints formed within the vicinity of the polymeric matrix. The results of the PSA detection tests in about 40 human sera were in perfect agreement with those of the reference ELISA method, demonstrating the robustness of the designed sensor. The second biosensor is an immunosensor dedicated to the determination of urinary EN2. Selectivity and competitiveness tests demonstrated that the immunosensor can selectively detect EN2 and differentiate it from other interfering proteins. Detection tests in artificial urine showed that the performance of the sensor was not affected by the complexity of the detection medium. The third sensor is a genosensor for the quantification of PCA3 extracted from urine samples. The chosen protocol is based on the grafting of thiolated DNA probes onto the gold surface of the working electrode and the recognition of PCA3 by complementarity, without the use of a redox couple or prior labelling of targets. Results highlighted that the choice of the probe, and more particularly the position of the sequence selected in the chain, has a significant influence on the response of the sensor