Bio-Interface Analysis and Detection of Aβ using GaN HEMT-based Biosensor

Early detection, prognosis, and diagnosis of devastating neurological disorders such as TBI and AD are crucial for developing treatment strategies, efficient patient outcomes, and management in biomedical fields. The work reports the design, development, suitability analysis, and validation of a label-free GaN HEMT-based biosensing platform for the non-invasive detection of FDA-approved biomarker A β in saliva sample concentration ranges. The biofunctionalization assay has been validated with both electrical and FTIR spectroscopy-based measurements. A comparative analysis with ELISA assay shows good agreement with ∼2.0% measurement errors demonstrating platform stability and accuracy for A β detection. The platform offers a peak sensitivity of 27.20 μ A/pg ml −1 , 19.10 μ A pg −1 ml −1 , and 1.48 μ A/pg ml −1 for detection in saliva, serum, and CSF concentration ranges with high specificity, excellent repeatability, and reproducibility of the results. The platform offers a sensitivity of 2.40 μ A/pg ml −1 , 15.40 μ A pg −1 ml −1 , and 27.20 μ A/pg ml −1 for S bias of 1.0 V, 3.3 V, and 5.0 V respectively. The key biosensor features include fast detection with a response time of 5–10 s and a low sample volume requirement of ∼1–2 μ l. The platform comparison with ELISA shows a similar and acceptable linearity trend. A novel equation has been established for ELISA and developed platform-based detection for possible detection accuracy and validation useful for correlating the sensor response with ELISA test results and vice-versa for any target A β concentrations. To the best of our knowledge, this is the first time reporting of A β detection using a GaN HEMT-based biosensing platform.