Evaluation of Aromatic Boronic Acids as Ligands for Measuring Diabetes Markers on Carbon Nano tube Field-Effect Transistors

Bio molecular detections performed on carbon nano tube field-effect transistors (CNT-FETs) frequently use reactive pyrenes as an anchor to tether bioactive ligands to the hydrophobic nano tubes. In this paper, we explore the possibility of directly using bioactive aromatic compounds themselves as CNT-FET ligands. This would be an efficient way to functionalized CNT-FETs since many aromatic compounds bind avidly to nano tubes, and it would also ensure that ligand-binding molecules would be brought in close proximity to the nano tubes. Using a model system consisting of pyrene, phenanthrene, naphthalene, or phenyl boronic acids immobilized on CNT-FET wafers, we show that all are able to bind glycated human serum albumin (gHSA), which is an important diabetes marker. Pyrene boronic acid proved to bind CNTs with the greatest apparent affinity as measured by gHSA impedance. Interestingly, gHSA CNT-FET signal intensity, which is proportional to amount of protein bound, remained essentially unchanged for all the boronic acids tested.