A reusable magnetic graphene oxide-modified biosensor for vascular endothelial growth factor detection in cancer diagnosis

Early cancer diagnosis is critical for the prevention of metastasis. However, simple and efficient methods are needed to improve the diagnosis and evaluation of cancer. Here, we propose a reusable biosensor based on a magnetic graphene oxide (MGO)-modified Au electrode to detect vascular endothelial growth factor (VEGF) in human plasma for cancer diagnosis. In this biosensor, Avastin is used as the specific biorecognition element, and MGO is used as the carrier for Avastin loading. The use of MGO enables rapid purification due to its magnetic properties, which prevents the loss of bioactivity. Moreover, the biosensor can be constructed quickly, without requiring a drying process, which is convenient for proceeding to detection. Our reusable biosensor provides the appropriate sensitivity for clinical diagnostics and has a wide range of linear detection, from 31.25-2000 pg mL(-1), compared to ELISA analysis. In addition, in experiments with 100% serum from clinical samples, readouts from the sensor and an ELISA for VEGF showed good correlation within the limits of the ELISA kit. The relative standard deviation (RSD) of the change in current (ΔC) for reproducibility of the Au biosensor was 2.36% (n=50), indicating that it can be reused with high reproducibility. Furthermore, the advantages of the Avastin-MGO-modified biosensor for VEGF detection are that it provides an efficient detection strategy that not only improves the detection ability but also reduces the cost and decreases the response time by 10-fold, indicating its potential as a diagnosis product.