Chemiluminescence flow biosensor for glucose based on gold nanoparticle-enhanced activities of glucose oxidase and horseradish peroxidase

In this work, a novel chemiluminescence (CL) flow biosensor for glucose was proposed. Glucose oxidase (GOD), horseradish peroxidase (HRP) and gold nanoparticles were immobilized with sol–gel method on the inside surface of the CL flow cell. The CL detection involved enzymatic oxidation of glucose to d-gluconic acid and H2O2, and then the generated H2O2 oxidizing luminol to produce CL emission in the presence of HRP. It was found that gold nanoparticles could remarkably enhance the CL respond of the glucose biosensor. The enhanced effect was closely related to the sizes of gold colloids, and the smaller the size of gold colloids had the higher CL respond. The immobilization condition and the CL condition were studied in detail. The CL emission intensity was linear with glucose concentration in the range of 1.0 × 10−5 mol L−1 to 1.0 × 10−3 mol L−1, and the detection limit was 5 × 10−6 mol L−1 (3σ). The apparent Michaelis–Menten constant of GOD in gold nanoparticles/sol–gel matrix was evaluated to be 0.3 mmol L−1, which was smaller than that of GOD immobilized in sol–gel matrix without gold nanoparticles. The proposed biosensor exhibited short response time, easy operation, low cost and simple assembly, and the proposed biosensor was successfully applied to the determination of glucose in human serum.