High-sensitivity creatine detection using doped ZnO nanoribbon biosensors: A density functional theory approach

Determining creatine concentration in the liver and kidneys is crucial for diagnosing health status due to its role as a significant biomarker in biosynthesis and muscle energy metabolism. This study proposes a two-terminal device made of hydrogen-passivated armchair ZnO nanoribbons connected between ZnO nanoribbon electrodes to explore its potential as a creatine biosensor. Using Transiesta, Tbtrans, and Density Functional Theory (DFT) calculations, the study evaluates the sensing capabilities of doped AZnONR for the first time. It involves hydrogen passivation, detailed doping analysis, and the assessment of electronic structure and adsorption properties to optimize biosensor performance. Measurements of PDOS, transmission coefficient, conductance, charge transfer, and electrostatic potential elucidate detection mechanisms, focusing on Al, Ga, and N doping effects. Findings reveal that creatine adsorption leads to the disappearance of some states near the conduction band edge due to charge transfer from the Al-doped ZnO nanoribbon. The projected density of states and transmission shift to higher energies because of creatine's negative electrostatic gating effect, significantly reducing transmission at 0.7 eV. A gate voltage of 0.7 V drastically alters the device's conductance, enabling creatine detection with 99.9 % sensitivity. The study highlights Al-doped ZnO nanoribbons' potential as highly sensitive creatine biosensors with an adsorption energy of −3.07 eV.