Au-decorated semiconducting AlN nanosheet as an electronic sensor for theophylline drug

Density functional theory calculations based on the TPSS functional were performed to investigate the potential application of the pristine AlN nanosheet (AlNNS) as well as the Au-decorated AlNNS (Au@AlNNS) in the detection of the theophylline (TP) drug. We found that the pristine sheet weakly adsorbed the drug, and its sensing response was about 6.0. After the Au-decoration on the AlNNS, the TP drug was powerfully adsorbed onto the Au@AlNNS with the adsorption energy of -1.33 eV, and the sensing response increased to 689.2. The localised molecular orbital energy decomposition analysis illustrated that the electrostatic attraction is stronger than the covalent interaction after the TP adsorption onto the Au@AlNNS. Based on the partial density of state analysis, the TP drug created a new state through the HOMO-LUMO gap of Au@AlNNS, which significantly increased the electrical conductivity. A short recovery time of 2.51 s was attained for the TP desorption from the Au@AlNNS surface. The water solvent weakened the adsorption process and decreased the sensing response to 524.6. Based on the results, we suggested the Au@AlNNS as a biosensor for the TP drug recognition.

Automated summary

Density functional theory calculations show that Au decoration on AlN nanosheet greatly enhances the adsorption capacity and sensing response for theophylline drug, making it a potential biosensor for drug recognition.