Harnessing a UiO-66-NH2/LaFeO3 nanocomposite for the electrochemical sensing of prednisone

Abstract

Prednisone is a synthetic corticosteroid that mimics cortisol by regulating blood pressure, the immune system, and inflammatory processes. Its widespread presence in biological systems underscores its involvement in various physiological processes. However, the long-term use of prednisone causes several side effects, rendering the detection of prednisone crucial. Electrochemical sensing has several advantages, including a simple instrumentation, high sensitivity, high selectivity, mobility, and the ability for on-site analysis. A sensor capable of detecting prednisone with an enhanced current response was developed using a UiO-66-NH₂/LaFeO₃ (ULFO) composite-modified glassy carbon electrode (GCE) at a low detection limit of 0.08 µM. The linear detection range is considered from 0.1 µM to 50 µM. The sensitivity of the ULFO-modified glassy carbon electrode was found to be 0.041 μA μM⁻¹. Morphological and physiological properties of the synthesized materials were investigated. Fourier transform infrared (FT-IR) spectra showed a broad band at around 3300–3500 cm⁻¹, corresponding to the stretching of the amino group. Bands near 1650–1550 cm⁻¹ (asymmetrical stretching) and 1400 cm⁻¹ (symmetrical stretching) correspond to the presence of carboxylate groups. The Fe–O stretching vibration at 490 cm⁻¹ indicates the presence of the FeO₆ octahedral structure. X-ray diffraction (XRD) was utilized to determine the crystallite size of the composite (0.84 nm). X-ray photoelectron spectra indicated partial hydroxylation of zirconium nodes, and scanning electron microscopy revealed the shape of UiO-66-NH₂ to be hexagonal and that of LaFeO₃ to be spherical. The composite showed uniform distribution of UiO-66-NH₂ on the LaFeO₃ surface. The redox activity of the ULFO composite was determined using cyclic voltammetry and differential pulse voltammetry, and the repeatability, reproducibility, selectivity, and stability were evaluated.