Ultrasensitive Detection of Lactate Dehydrogenase Using GaN HEMT Sensors

As one of the routine biomarkers for tissue or organ injuries and damage due to various reasons, lactate dehydrogenase (LDH) is expressed extensively in biological tissues. LDH can be found in serum and other body biofluids, such as tears, urine, and sweat. Monitoring the level changes in these body biofluids is one of the clinic routines to assess the extent of tissue or organ damage, disease progression, or response to treatment. Herein, GaN high electron mobility transistor (HEMT) sensors for detecting LDH are reported. Before detecting LDH, EDC/NHS chemistry was used to functionalize the gate region (i.e., sensing surface) of the HEMT sensors with the LDH antibody. It has been found that this type of sensor can detect LDH with a level as low as ∼10 fg/mL, which is the best among previously reported LDH sensors. It has been found that the response time of the sensor is less than 60 s, and it has very high specificity and can monitor LDH in serum samples successfully. Given its simple-to-use, low-cost, ultrasensitivity, and rapid response time, this type of LDH sensor is a particularly attractive toolset for point-of-care (POC) applications. In addition, the biocompatibility and long-term durability of GaN-based sensors in harsh environments render them particularly attractive as implantable devices for biomedical applications.