A turn off-on fluorometric and paper based colorimetric dual-mode sensor for isoniazid detection

Green synthesis of CQDs for determination of iron and isoniazid in pharmaceutical formulations

Camphor leaves were used as the precursor for the hydrothermal synthesis of carbon quantum dots. The preparation method is simple and rapid, and the raw material is environmentally friendly and easy to obtain. Without additional modification, the carbon quantum dots were used as fluorescent probes for the sensitive and selective detection of Fe³⁺ and isoniazid at different excitation wavelengths. For Fe³⁺, at the excitation wavelength of 320 nm, the ratio of fluorescence intensity of CQD solution after adding Fe³⁺ to CQD solution without Fe³⁺ addition, F/F₀, and Fe³⁺ concentration showed a good linear relationship in the range of 2.72 × 10^-5 to 1.00 × 10^-4 mol L^-1 (R² = 0.9912), and the limit of detection was 8.16 μmol L^-1. For isoniazid, at the excitation wavelength of 270 nm, the ratio of fluorescence intensity of CQDs solution with isoniazid to CQDs solution without isoniazid, F/F₀, and isoniazid concentration showed good linear relationships in the range of 3.81 × 10^-6 to 1.00 × 10^-5 mol L^-1 (R² = 0.9941) and 1.00 × 10^-5 to 2.10 × 10^-4 mol L^-1 (R² = 0.9910) respectively, and the limit of detection was 1.14 μmol L^-1. A fluorescence method for the determination of Fe and isoniazid content was proposed. The method has been used to detect iron in iron supplement tablets and isoniazid in isoniazid tablets with satisfactory results.

Novel β-cyclodextrin doped carbon dots for host-guest recognition-assisted sensing of isoniazid and cell imaging

In the present study, novel β-cyclodextrin doped carbon dots (CCDs) were prepared via a simple one-pot hydrothermal method at a mild temperature (140 °C), using mixtures of β-cyclodextrin and citric acid as precursors. By characterizing the chemical properties of CCDs prepared at 140 °C and 180 °C, the importance of low-temperature reaction for preservation of the specific structure of β-CD was elucidated. The CCDs showed excellent optical properties and were stable to changes in pH, ionic strength and light irradiation. Since the fluorescence of the CCDs could be selectively quenched by isoniazid (INZ) through specific host-guest recognition effects, a convenient isoniazid fluorescence sensor was developed. Under the optimal conditions, the sensor exhibited a relatively low detection limit of 0.140 μg mL^-1 and a wide detection range from 0.2 μg mL^-1 to 50 μg mL^-1 for INZ detection. Furthermore, the sensor was employed successfully for the determination of INZ in urine samples with satisfactory recovery (91.1-109.5%), displaying potential in clinical applications. Finally, low cytotoxicity of the prepared CCDs was confirmed using the CCK-8 method, followed by application in HepG2 cell imaging.

Fabrication of a Tubular CuO/NiO Biomimetic Nanozyme with Synergistically Promoted Peroxidase-like Performance for Isoniazid Sensing

Isoniazid is an antibiotic primarily used in clinical treatment of tuberculosis, but excessive usage can lead to serious consequences such as hepatotoxicity, neurotoxicity, and even coma and death. Therefore, it is critical to exploit a quick, facile, and acute way for isoniazid analysis. In this work, we have demonstrated an efficient electrospinning-carbonation-wet chemistry reaction-calcination process to fabricate CuO/NiO nanotubes (NTs) as a promising nanozyme for peroxidase (POD) mimicking. In virtue of the distinct tubular structure and synergy between CuO and NiO from the mechanisms of both electron transfer and hydroxyl radical generation, a remarkably improved catalytic activity is realized for the CuO/NiO NTs compared with bare CuO and NiO samples. According to the admirable POD-like property, a rapid colorimetric detection for isoniazid is accomplished with a detection limit of 0.4 μM (S/N = 3) and favorable selectivity. In addition, the sensing capability of isoniazid in a real sample is also investigated with satisfactory results. This work offers a novel tactic to fabricate high-performance nanozymes with efficient isoniazid sensing capabilities to address challenges in disease treatment efficacy and public safety monitoring.