Therapeutic drug monitoring (TDM) is crucial for optimizing the treatment of staphylococcus aureus pneumonia, ensuring effectiveness and preventing the development of resistant bacterial strains, typically requiring linezolid (LIN) therapy. A novel electrochemical nanosensor was developed based on a carbon paste electrode modified with Ni-Fe layered double hydroxide/graphitic carbon nitride (NiFe LDH-GCN/CPE) for the sensitive and selective quantification of the anti-pneumonia drug LIN in human plasma. For this purpose, NiFe-LDH was synthesized using a hydrothermal method, while GCN was prepared through the thermal condensation of melamine. The obtained nanostructures were comprehensively characterized using X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, N2 adsorption-desorption measurements, field emission scanning electron microscopy (FESEM), and energy-dispersive X-ray (EDX) analysis. Subsequently, the electrochemical behavior of the prepared electrodes was investigated using a range of analytical techniques, including cyclic voltammetry (CV), linear sweep voltammetry (LSV), chronoamperometry (CHA), chronocoulometry (CHC), and square wave voltammetry (SWV). The modified carbon paste electrode (NiFe LDH-GCN/CPE) exhibited superior electrocatalytic activity, low charge transfer resistance (Rct ≈ 360 Ω and a large electroactive surface area (0.86 cm2). The quantification of LIN in 0.1 M phosphate buffer solution (PBS) was carried out using the fabricated nanosensor under optimized conditions determined by response surface methodology, including pH 7.0, a scan rate of 0.05 V s− 1, and 0.04 g of NiFe–LDH and GCN incorporated into the sensor composition. The catalytic rate constant (kcat) and diffusion coefficient (D) were determined to be 1.7 × 108 cm3 mol− 1 s− 1, and 1.17 × 10− 8 cm2 s− 1, respectively. The NiFe LDH-GCN/CPE showed superior performance with SWV, achieving a limit of detection (LOD) of 0.09 µM and a linear dynamic range (LDR) of 0.30-133.02 µM. In contrast, CV had an LOD of 0.41 µM and an LDR of 1.34–142.28 µM, indicating that SWV provides better sensitivity and a wider range for LIN detection. The practical applicability of the nanosensor was demonstrated by successfully quantifying LIN in human serum samples, with recovery rates ranging from 98.2% to 102.2% and RSD values of less than 2.6%. The fabricated nanosensor demonstrated satisfactory selectivity, favorable repeatability, and reproducibility, making it a reliable analytical tool for quantifying LIN in biological matrices.

Development of a Newly Designed Electrochemical Sensor Based on NiFe Layered Double Hydroxide/Graphitic Carbon Nitride Nanocomposites for the Determination of Anti-pneumonia Linezolid Drug

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发表日期：

2026年2月28日

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Kooshan Kaveh,
Seyed Karim Hassaninejad-Darzi,
Behrooz Eftekharinia

摘要

Therapeutic drug monitoring (TDM) is crucial for optimizing the treatment of staphylococcus aureus pneumonia, ensuring effectiveness and preventing the development of resistant bacterial strains, typically requiring linezolid (LIN) therapy. A novel electrochemical nanosensor was developed based on a carbon paste electrode modified with Ni-Fe layered double hydroxide/graphitic carbon nitride (NiFe LDH-GCN/CPE) for the sensitive and selective quantification of the anti-pneumonia drug LIN in human plasma. For this purpose, NiFe-LDH was synthesized using a hydrothermal method, while GCN was prepared through the thermal condensation of melamine. The obtained nanostructures were comprehensively characterized using X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, N₂ adsorption-desorption measurements, field emission scanning electron microscopy (FESEM), and energy-dispersive X-ray (EDX) analysis. Subsequently, the electrochemical behavior of the prepared electrodes was investigated using a range of analytical techniques, including cyclic voltammetry (CV), linear sweep voltammetry (LSV), chronoamperometry (CHA), chronocoulometry (CHC), and square wave voltammetry (SWV). The modified carbon paste electrode (NiFe LDH-GCN/CPE) exhibited superior electrocatalytic activity, low charge transfer resistance (R_ct ≈ 360 Ω and a large electroactive surface area (0.86 cm²). The quantification of LIN in 0.1 M phosphate buffer solution (PBS) was carried out using the fabricated nanosensor under optimized conditions determined by response surface methodology, including pH 7.0, a scan rate of 0.05 V s^− 1, and 0.04 g of NiFe–LDH and GCN incorporated into the sensor composition. The catalytic rate constant (k_cat) and diffusion coefficient (D) were determined to be 1.7 × 10⁸ cm³ mol^− 1 s^− 1, and 1.17 × 10^− 8 cm² s^− 1, respectively. The NiFe LDH-GCN/CPE showed superior performance with SWV, achieving a limit of detection (LOD) of 0.09 µM and a linear dynamic range (LDR) of 0.30-133.02 µM. In contrast, CV had an LOD of 0.41 µM and an LDR of 1.34–142.28 µM, indicating that SWV provides better sensitivity and a wider range for LIN detection. The practical applicability of the nanosensor was demonstrated by successfully quantifying LIN in human serum samples, with recovery rates ranging from 98.2% to 102.2% and RSD values of less than 2.6%. The fabricated nanosensor demonstrated satisfactory selectivity, favorable repeatability, and reproducibility, making it a reliable analytical tool for quantifying LIN in biological matrices.