Fabrication of Eu3+/Tb3+-co-doped zirconia electrospun nanofibers as a multicolored photoluminescence sensor for the determination of levodopa

Abstract

In this study, ZrO₂:Eu³⁺:Tb³⁺ nanoparticles were synthesized by a microwave-assisted approach to determine levodopa, the precursor of the neurotransmitter dopamine. Dopamine, as a catecholamine, can pass across the blood-brain barrier to enter the central nervous system and treat Parkinson's disease. The identification of levodopa's harmful effects has enabled the development of a variety of analytical approaches. The fluorescence sensor was employed in this study due to its advantageous characteristics, including precise measurement capabilities and rapid response times. Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, high-resolution transmission electron microscopy, diffuse reflectance spectroscopy, and UV–vis and fluorescence spectrophotometers were employed to examine the optical, microscopic, and spectroscopic characteristics of these nanoparticles. The sensor's efficiency was evaluated by detecting levodopa with a recovery percentage of 86–99 % in human blood serum and 97–102 % in urine from actual human samples. The mechanism in the interaction between levodopa and nanoparticles was explored using UV–vis spectroscopy, which indicated that the PET mechanism was responsible for the observed quenching. The sensitivity of the sensor was also determined by the lowest detection limit of 91 nM, which was achieved by examining the effects of levodopa on the sensor in the linear range of 1–100 µM. Furthermore, the sensor exhibited excellent stability and selectivity. The sensor was constructed using electrospun polyacrylonitrile (PAN) nanofibers, which were deemed more innovative and practical than paper substrates. Additionally, an orange-emitting ZrO₂:Eu³⁺:Tb³⁺ sensor based on PAN was employed to assess levodopa visually.