This work details the successful fabrication and demonstration of a liquid-gated SWCNT FET sensor modified with CatE-binding peptide aptamers as an attractive platform for POCT application for the detection of unreached disease biomarkers such as serum CatE, which has recently been highlighted as a novel prognostic biomarker for cancer because the reduction of serum level of CatE has been associated with poor prognosis in breast cancer patients20. Here, CTSE is linked to breast cancer.