Highly sensitive non-enzymatic electrochemical glucose biosensor using a photolithography fabricated micro/nano hybrid structured electrode

• We report a highly sensitive non-enzymatic glucose biosensor based on a simple photolithographic process.
• A uniform micro/nano hybrid structured electrode of gold was fabricated.
• The sensing area was measured to be enhanced by 10.2 folds.
• The linear range, sensitivity, and limit of detection were measured to be 55.6 μM–13.89 mM, 749.2 μA mM−1 cm−2, and 9 μM, respectively.

In this study, a novel non-enzymatic glucose biosensor based on a simple photolithographic process is proposed. To fabricate the sensor, photoresist AZ-1518 was spin-coated onto a reclaimed silicon wafer, and then, a mask with a hexagonal close-packed circle array was employed for exposure and development to generate a hexagonal close-packed column array of AZ-1518. The diameter of each circle was set as 3 μm. Subsequently, a thermal melting process was employed to convert each photoresist column into a photoresist hemisphere. A gold thin film was then sputtered onto the hemisphere array of AZ-1518 to form the sensing electrode. Finally, gold nanoparticles were deposited onto the gold thin film using a self-assembly monolayer method to enhance the sensing area. Measurements showed a 10.2-fold enhancement of the sensing area in comparison with a plain gold electrode. Actual detection of glucose demonstrated that the proposed non-enzymatic glucose biosensor can operate in a linear range of 55.6 μM–13.89 mM. It had a sensitivity of 749.2 μA mM−1 cm−2 and a detection limit of 9 μM. The novel glucose biosensor proposed here has several advantages such as being enzyme free, simple to fabricate, low cost, and easy to preserve on a long-term basis. Thus, it can feasibly be used for future clinical applications.