Radical prostatectomy is currently the most used curative procedure in the treatment of localised prostate cancer (PCa). However, in 30-50% of interventioned patients Prostate Specific Antigen (PSA) increases on post-operatory, meaning that the cancer has spread. The rise in PSA is due to imprecision in preoperative staging, suggesting patients already had distant, undetectable disease. Another issue is that elevated serum PSA is not specific to malignant prostate disease, it cannot differentiate between indolent tumours or those that are/will become life threatening. Fatal cancer is most often due to metastatic disease but histopathological examination of biopsy or traditional imaging methods fail to detect the early disseminated circulating biological information highlighting the need for approaches that can detect biomarkers of cancer spreading at an early stage. Circulating amounts of non-coding microRNA (miRNA) have been shown to have a biological impact and to be clinically associated with cancer and are now seen as a new class of biomarkers that will allow earlier and more accurate diagnosis. The objective of INFORM is to develop an innovative electrochemical multiplex biosensor for detection and quantification of a panel of clinically relevant circulating miRNAs in intermediate-risk PCa patients that will be submitted to potentially curative surgery. By focusing on the development, optimisation and validation of a biosensor for miRNA profiling in PCa, discrimination of patients with local disease from those with more advanced PCa will be possible. The biosensor will rely on the selectivity of the sandwich assays and on the sensitivity of the photoelectrochemical detection to quantify, at the sub-fM level, circulating miRNAs that are associated with PCa. The quantification of these overexpressed miRNAs will lead to a better overall management of the disease and allow for a more informed decision by the medical doctor, providing personalised medicine.