A general strategy to prepare homogeneous and reagentless GO/lucigenin&enzyme biosensors for detection of small biomolecules

In this work, a novel biosensor was developed for the detection of glucose based on glucose oxidase (GOD) functionalized graphene oxide (GO)/lucigenin nanocomposite. In this sensing strategy, GO/lucigenin composite was first prepared by vigorously stirring GO with lucigenin. Then the functionalization of GOD was achieved by simply storing GOD with GO/lucigenin at 4 °C overnight to form GO/lucigenin&GOD composite. When glucose was incubated with GO/lucigenin&GOD composite for 50 min to generate H2O2, followed by the injection of 0.2 M NaOH, CL signal was detected due to the reaction of lucigenin with H2O2. Glucose could be determined in the range of 1.0×10−6-5.0×10−3 g mL−1 with a detection limit of 9.9×10−7 g mL−1. The present biosensor has been successfully applied for the detection of glucose in human serum samples. Compared with previously reported methods, this sensing strategy is homogeneous and reagentless and avoids complicated assembly procedure and pretreatment of serum sample, showing good stability, repeatability, high selectivity and simplicity. Moreover, this strategy has been demonstrated to be a general strategy by replacing GOD with other enzymes such as uricase and choline oxidase for the detection of small molecules such as uric acid and choline. The proposed biosensors may find future applications in the fields such as disease diagnosis and biomedicine.