Improvement of glucose detection using 10 nm Al2O3 thin film on diamond solution-gate field-effect transistor

Glucose detection is crucial for diagnosis, prevention and treatment of diabetes mellitus. In this work, 10 nm Al2O3 thin film was introduced on the channel of diamond solution-gate field-effect transistor (SGFET) to improve the performance of glucose detection. AFM results show the roughness of channel surface increased after Al2O3 thin film deposition. Then, 1-pyrenebutyric acid-N-hydroxy succinimide ester (Pyr-NHS) and glucose oxidase (GOD) were linked on the channel. The morphology after each modification step was evaluated by SEM, and the result indicated an uneven Al2O3 distribution. XPS spectra further confirmed the effective modification of Pyr-NHS and GOD. In addition, the shifts of transfer characteristics for each concentration of glucose were analyzed, which illustrated a wide linear response (10−8-10−2 M), a high sensitivity (−44.01 mV/log10[glucose concentration]) and a low detection limitation (10−8 M). All these results show an excellent detection performance, which may provide a new idea for the design of diamond SGFET biosensor. [Display omitted] •Diamond solution gate field effect transistor with 10 nm Al2O3 was prepared.•Detection limitation of glucose was lowered to 10−8 M.•Al2O3 thin film enhance the performance of diamond biosensor.