A non-enzymatic electrochemical biosensor for the detection of phenylalanine using bismuth telluride nanosheets

In newborns, phenylketonuria occurs due to the disruption in the breakdown of phenylalanine (Phe). Phe is an essential amino acid, which is involved in the biosynthesis of proteins and the regulation of neurotransmitter hormones. Deficiency of Phe causes damage to the brain and nervous system, further leading to the development of epileptic seizures. In this aspect, a non-enzymatic electrochemical sensor based on bismuth telluride nanosheets (Bi₂Te₃) was developed for the detection of Phe. The scanning electron microscopy image confirmed the layer-like structure of the solvothermally synthesized Bi₂Te₃. XPS data indicated the presence of Bi³⁺ and Te^2- species, which enhanced the charge transfer during electrochemical oxidation of Phe. This sensor effectively detected Phe in the range from 5 nM-863 μM, with a detection limit of 3.03 nM and a quantification limit of 9.09 nM. The sensor performance was examined in the presence of spiked Phe in human blood serum samples. The figure of merits of the surface-modified electrode with electrocatalytic efficiency make it suitable for the real-time detection of Phe.