Hepatocellular Carcinoma Detection by Cell Sensor Based on Anti-GPC3 Single-Chain Variable Fragment

Precise identification of hepatocellular carcinoma (HCC) in early stages remains both a challenge and an opportunity for prevention and diagnosis of early liver cancer. Fast-detecting techniques like electrochemical sensing might provide more insight than current clinical methods owing to its high sensitivity, rapid detection, and convenient operation. Here, a single-chain variable fragment (scFv) was designed by retaining the antigen binding active sites of a recombinant humanized monoclonal antibody and modifying with histidine tags, and consequently used for the construction of cell sensor for HCC detection. The customized scFv showed specific binding signature on the membrane of HCC cell and positive correlation with cell concentration using fluorescence confocal microscopy and flow cytometry, respectively. A higher binding affinity of scFv over the original monoclonal antibody was also displayed. After the immobilization onto the screen-printed electrode through the high affinity between histidine and nickel-based nanomaterial, the constructed cell sensor exhibited a wide detection range of 102 to 107 cells ml−1 and a low detection limit of 2 cells ml−1 with a short incubation time of 5 min. The high selectivity in the liver tissue extract fluid derived from the design strategy was also displayed in the mouse samples. The customized scFv and related cell sensor demonstrated great potential for fast HCC analysis in early-stage cancer diagnosis.