Novel Enzymatic Reagentless Glucose Biosensors Based on Noble Metal Nanostructures

Reagentless glucose biosensors with redox mediator-polymerized 1,10-phenanthroline-5,6-dione (pPD)-were developed and electrochemically investigated. Three types of biosensors based on graphite rod (GR) electrodes modified by (i) 13 nm of gold nanoparticles (AuNPs), (ii) electrochemically synthesized dendritic gold nanostructures (DAuNSs), and (iii) platinum nanostructures (PtNSs) were prepared. All electrodes were modified by glucose oxidase (GOx), and the pPD was polymerized for 2 h. Thus, GR/AuNPs/GOx/pPD, GR/DAuNSs/GOx/pPD, and GR/PtNSs/GOx/pPD electrodes were developed and electrochemically characterized. The electrode without noble metal nanostructures (GR/GOx/pPD) was used as the control. The biosensor based on the GR/DAuNSs/GOx/pPD electrode exhibited the best performance, with the sensitivity of 2.58 μA/(mM cm²), the linear range up to 93.7 mM, the limit of detection 0.182 mM, the reproducibility and repeatability of 4.99 and 4.80%, and the storage stability (50% of initial current responses (t_1/2)) for up to 19 days. The achieved high resistance to interfering materials enabled precise glucose detection in real samples, including human serum and beverages. The technological solutions presented in this paper are anticipated to provide opportunities and benefits of developing novel enzymatic reagentless glucose biosensors based on noble metal nanostructures for use in clinical assays and general diagnostics, including blood glucose monitoring in people with diabetes.