Paper-based electrochemical immunosensor for rapid and inexpensive cancer biomarker protein detection

C.K. Tang, A. Vaze, J.F. Rusling
University of Connecticut, US

Keywords: paper, electrochemical, cancer biomarkers, immunosensor

Summary:

Inexpensive, reusable electrochemical sensor chips with on-chip reference and counter electrodes were fabricated from gold compact discs using simple wet etching technique. A complete electrochemical senor cell was constructed by employing a filter paper disk wetted with aqueous solution. The filter paper disk equipped with capture antibodies was developed into an immunosensors cell following a dip-incubate-wash cycles to accumulate protein analytes and label enzymes in a sandwich immunoassay protocol. The labels are detected after placing the wet disk on the sensor chip. Total assay time from antigen immobilization to qualitative results was greatly reduced from 2.5 hrs to ~15 mins as compared to traditional electrochemical assays. Detection limits of 6 pg mL-1 for PSA were obtained in serum mixtures and the sensor dynamic range encompasses clinically relevant levels. The present work presents a promising low cost rapid point of care diagnostic tool for cancer biomarkers detection through the integration of electrochemical detection with a simple paper based device.