Multienzyme decorated polysaccharide amplified electrogenerated chemiluminescence biosensor for cytosensing and cell surface carbohydrate profiling

A novel ECL biosensor for cytosensing and cell surface carbohydrate expression evaluation was developed, by the integration of the peptide modified interface for highly specific carbohydrate recognition and sodium alginate loaded glucose oxidase as the signal probe with high signal amplification efficiency. A cysteine-terminated peptide self-assembled on the electrode through Au–S bond to construct a functional interface for cell capture, with decent biocompatibility and high affinity for the human breast cancer cell MCF-7. Concanavalin A lectin modified gold nanoparticles specifically recognized the cell surface carbohydrates and were absorbed on the electrode, followed by the immobilization of multiple glucose oxidase conjugated sodium alginate, which could remarkably increase the sensitivity of the biosensor with enhanced catalysis. The as-proposed ECL cytosensor was successfully applied for the detection of the MCF-7 tumor cells, whose glycans on the cell membranes are over-expressed. A low detection limit of 150 cells mL−1 was obtained, with a wide dynamic linear range from 5.0×102 to 5.0×105 cells mL−1. Due to the excellent sensitivity, stability and biocompatibility, the ECL biosensor would be promising in reliable diagnostics of glycan relevant biomarkers for cancer and other diseases.