Label-free nanoplasmonic sensing of tumor-associate autoantibodies for early diagnosis of colorectal cancer

•A nanoplasmonic biosensor for colorectal cancer autoantibody detection is proposed.•Direct, label-free detection of TAA autoantibodies is achieved with LOD around 1 nM.•The strategy allows the detection in serum and plasma after a 1:10 dilution step.•Real samples from cancer patients have been analyzed and compared with ELISA.

Colorectal cancer is treatable and curable when detected at early stages. However there is a lack of less invasive and more specific screening and diagnosis methods which would facilitate its prompt identification. Blood circulating autoantibodies which are immediately produced by the immune system at tumor appearance have become valuable biomarkers for preclinical diagnosis of cancer. In this work, we present the rapid and label-free detection of colorectal cancer autoantibodies directly in blood serum or plasma using a recently developed nanoplasmonic biosensor. Our nanoplasmonic device offers sensitive and real-time quantification of autoantibodies with excellent selectivity and reproducibility, achieving limits of detection around 1 nM (150–160 ng mL−1). A preliminary evaluation of clinical samples of colorectal cancer patients has shown good correlation with ELISA. These results demonstrate the reliability of the nanobiosensor strategy and pave the way towards the achievement of a sensitive diagnostic tool for early detection of colorectal cancer.

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