AlGaN/GaN HEMT-Based Detection of Reactive Oxygen Species Molecule H2O2

Abstract

Abstract Body: AlGaN/GaN high electron mobility transistors (HEMTs) have been extensively studied for biochemical sensing applications due to their high sensitivity to surface phenomena, fast response time, aqueous stability, and biocompatibility [1]. In HEMT sensors, the two-dimensional electron gas (2DEG) acts as a highly conductive channel that can be modulated by changes in the surface potential. The detected signal in the gate region is amplified and measured as a change in the 2DEG conductivity, which makes the HEMT a good sensing device. Due to their unique electrical and chemical properties, AlGaN/GaN HEMTs show great potential for the detection of reactive and transient biological components, such as reactive oxygen species (ROS). In this study, we demonstrate the potential of AlGaN/GaN HEMT sensors for the detection of ROS molecules such as hydrogen peroxide (H2O2) [2]. A boronate-based fluorescent probe was used with this device to detect the presence of micromolar levels of hydrogen peroxide typically associated with intracellular processes. A non-functionalized, non-metallized open-gate AlGaN/GaN HEMT sensor is employed in this study. The real-time progression of the reaction is monitored by measuring the modulation of the 2DEG current in response to changes in the surface potential caused by the interaction between the semiconductor surface states and the products of the reaction. The electrical response of the HEMT sensor showed a gradual decrease in the 2DEG current as the reaction proceeded over time. A corresponding increase in the emission intensity was measured from the fluorescent probe with the progression of the reaction. The fluorescence from the boronate probe was used as an indicator to confirm the detection of H2O2. The response of our HEMT sensor shows its applicability to the detection of micro-molar concentrations of H2O2, which is in the range typically present in intracellular processes of living systems [3]. The results from this study demonstrate the possibilities of interfacing biocompatible electronics with existing bioorthogonal probes to expand the capabilities of existing fluorescent probe-based detection techniques. [1] F. Ren and S.J. Pearton, Phys. Status Solidi C 9, 393 (2012). [2] I. Mahaboob, R. J. Reinersten, B. McEwen, K. Hogan, E. Rocco, J. A. Melendez, N. Cady, and F. Shahedipour-Sandvik. Exp. Biol. Med. (2020). [3] V. S. Lin, B. C. Dickinson, and C. J. Chang. Methods Enzymol. 526, 19–43 (2013).