Ultrasensitive label-free tobramycin detection with aptamer-functionalized ZnO TFT biosensor

Aminoglycoside antibiotic such as tobramycin is critical to the treatment of Gram-negative bacterial diseases such as Cystic Fibrosis (Pseudomonas aeruginosa) and other respiratory problems routinely seen in military personnel. Bottom gate (BG) zinc oxide (ZnO) ultra-thin film transistors (TFTs) were fabricated and functionalized with thiol-anchored aptamers as sensitive tobramycin biosensors and a Lower Detection Limit (LDL) of 0.1 nM was extracted from the adsorption coverage isotherm. Sputter deposition of (ZnO) allows the control of film thickness, stoichiometry, defects and interface states. Intrinsically high surface morphology of ZnO allows improved aptamer functionalization and sensitivity of detection.