Enhanced electrocatalytic oxidation of isoniazid at electrochemically modified rhodium electrode for biological and pharmaceutical analysis

Facile synthesis of copper carbonate analog with peroxidase-like activity for colorimetric detection of isoniazid

In this article, copper carbonate analog with good peroxidase-like activity was successfully synthesized for the first time via a simple co-precipitation of CuSO4▪5H2O and Na2CO3. The obtained copper carbonate analog exhibited excellent intrinsic peroxidase-like activity towards a classical peroxidase substrate of 3, 3', 5, 5' -tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H2O2) under an acidic environment. The study of the catalytic mechanism confirmed that the hydroxyl radical produced from the decomposition of H2O2 is the main reactive oxygen species responsible for the catalytic oxidation of TMB to oxTMB. Moreover, results from kinetic parameter analysis indicated that H2O2 was more easily and/or likely to attach to the copper carbonate analog than TMB. Subsequently, the effects of experimental conditions (buffer pH, temperature, and incubation time) on the catalytic activity of the copper carbonate analog were also optimized. Finally, a copper carbonate analog-based colorimetric sensor was developed to determine isoniazid. Under the optimal conditions, the linear range for isoniazid was as broad as 0-178.6 μM, and the detection limit was as low as 8.47 μM. The spiked recoveries of isoniazid in normal human serum has been observed in the range of 94.8%-105.5 %. This strategy focuses on the development of a green, cost-efficient peroxidase mimic with high activity, good biocompatibility, and a simple synthesis process.

Multifunctional Fe/Cu Dual-Single Atom Nanozymes with Enhanced Peroxidase Activity for Isoniazid Detection and Levofloxacin Degradation

The design of single-atom nanozymes with dual active sites to increase their activity and for the detection and degradation of contaminants is rare and challenging. In this work, a single-atom nanozyme (FeCu-NC) based on a three-dimensional porous Fe/Cu dual active site was developed as a colorimetric sensor for both the quantitative analysis of isoniazid (INH) and the efficient degradation of levofloxacin (LEV). FeCu-NC was synthesized using a salt template and freeze-drying method with a three-dimensional hollow porous structure and dual active sites (Fe-Nx and Cu-Nx). In terms of morphology and structure, FeCu-NC exhibits excellent peroxidase-like activity and catalytic properties. Therefore, a colorimetric sensor was constructed around FeCu-NC for sensitive and rapid quantitative analysis of INH with a linear range of 0.9-10 μM and a detection limit as low as 0.3 μM, and the sensor was successfully applied to the analysis of INH in human urine. In addition, FeCu-NC promoted the efficient degradation of LEV by peroxymonosulfate activation, with a degradation rate of 90.4% for LEV at 30 min. This work sheds new light on the application of single-atom nanozymes to antibiotics for colorimetric sensing and degradation.

Development of recycled and miniaturized electroanalytical sensor: Probing isoniazid determination in environmental water matrices

Surface water pollution has become relevant because growing population and intense industrial activities. Thus, to protect the environment from contamination, recently the electroanalytical sensors that require small sample volume and easy preparation have shown a prominent performance for pharmaceuticals monitoring. For this purpose, a miniaturized electrochemical platform was developed based on recycling obsolete computer integrated circuits (microchips), fitting with the ideals of green chemistry and circular economy. The gold microelectrodes array (Au-μEA) was easily exposed by polishing the device surface and then characterized by optical microscopy, scanning electron microscopy and cyclic voltammetry. To enhance the analytical performance for isoniazid detection, the Au-μEA was modified with electrochemically reduced graphene oxide (ERGO). The developed sensor presented a linear range between 5 and 100 μmol L-1 and a limit of detection of 1.38 μmol L-1 demonstrating a reliable performance. Looking to its environmental application, the ERGO/Au-μEA sensor was used for isoniazid quantification in lagoon, river, tap water and synthetic effluent spiked samples with recovery values between 92.5 and 108.4%. Thus, this research field opens up new possibilities in global water-related issues contributing with innovative sustainable solutions.

One-step preparation of N-doped grapheme quantum dots with high quantum yield for bioimaging and highly sensitive electrochemical detection of isoniazid

Conventional techniques for synthesizing GQDs have a poor quantum yield (QY) that restricts their biological applications. Herein, we present a rapid, cost-effective and high quantum yield synthesis of nitrogen-doped graphene quantum dots (N-GQDs) through a scientific microwave reactor. The reaction parameters like microwave irradiation time, temperature, precursor concentration and pressure were optimized for achieving high quantum yield. The prepared N-GQDs exhibit bright blue fluorescence and excitation independent emission property with a quantum yield of 42.81%. In-vivo investigations on C. elegans revealed that the as-prepared N-GQDs are exceptionally biocompatible and maintain the normal physiological functioning of the primary and secondary targeted organs in nematodes. The synergetic effect of intestinal barrier and defecation behavior mitigates N-GQDs translocation into reproductive organs of nematode. In addition, the N-GQDs modified GCE was tested for electrochemical sensing characteristics towards the anti-tuberculosis drug isoniazid (INZ). The N-GQDs showed appreciable electrocatalytic performance towards INZ with high sensitivity (3.76 μA μM^-1 cm^-1). The differential pulse voltammetry (DPV) analysis of N-GQDs exhibit a lower detection limit of 10.91 nM for INZ. The N-GQDs modified sensor exhibits good reproducibility, excellent anti-interference ability and excellent analytical performance for INZ in real samples like human blood serum and urine samples.

A simple signal-on strategy for fluorescent detection of tuberculostatic drug isoniazid based on Ag clusters-MnO2 sheets nanoplatform

As a first-line tuberculostatic drug, isoniazid (INH) plays effective and irreplaceable role in prevention and treatment of tuberculosis. In this work, a rapid and simple signal-on fluorescence approach is established for INH assay by employing a platform composed of silver nanoclusters (AgNCs) and MnO₂ nanosheets. In the proposed sensing system, strong red fluorescence of poly (methacrylic acid)-stabilized AgNCs can be greatly quenched after they attach to the surfaces of MnO₂ nanosheets. With the addition of INH, MnO₂ nanosheets are reduced to Mn²⁺ and subsequently release the AgNCs, which leads to obvious fluorescence recovery again. Based on this mechanism, highly sensitive detection of INH in the range of 0.8-200 μM is realized (detection limit: 476 nM). The present strategy shows remarkable advantages including simplicity, rapidness, high sensitivity and wide detectable range. This method is also practical and comparable to high-performance liquid chromatography, which can be applied to detect INH in human urine and serum samples as well as pharmaceutical products.

Synthesis and characterization of maltol capped silver nanoparticles and their potential application as an antimicrobial agent and colorimetric sensor for cysteine

Maltol capped silver nanoparticles (McAgNPs) were synthesized using maltol (3-hydroxy-2-methyl-4-pyrone) as reducing and capping agent. McAgNPs were characterized by Visible and FTIR (Fourier transform infrared) spectroscopy, dynamic light scattering (DLS), and atomic force microscopy (AFM). Bright yellow color McAgNPs showed surface plasmon resonance (SPR) band at 436 nm, spherical shape and the average size between 35 to 50 nm. McAgNPs revealed higher stability against varying storage time, temperature, pH and salt concentrations. McAgNPs were successfully utilized for the selective and highly sensitive colorimetric detection of cysteine (Cys). Addition of Cys in a solution of McAgNPs, resulted a rapid change in color from yellow to orange because of the formation of nanoaggregates as confirmed by Visible/FTIR spectroscopy, DLS, and AFM studies. The estimated limit of detection (0.043 μM) was found to be more sensitive than previously reported other optical methods. The practical applicability of probe was also established by spiking the known concentrations of Cys in biological (blood plasma and urine) and environmental (tap and lake water) samples with significant recovery rates (92-104.6%). Despite being nontoxic to various tested cell lines, McAgNPs demonstrated potent antimicrobial, antibiofilm, and biofilm eradicating activities, thus potentially valuable in diagnostics and/or the synthesis of other nanocomposite material for broader applications.

Electroanalysis of isoniazid and rifampicin: Role of nanomaterial electrode modifiers

Thanks to operational simplicity, speediness, possibility of miniaturization and real-time nature, electrochemical sensing is a supreme alternative for non-electrochemical methodologies in drug quantification. This review, highlights different nanotech-based sensory designs for electroanalysis of isoniazid and rifampicin, the most important medicines for patients with tuberculosis. We first, concisely mention analyses with bare electrodes, associated impediments and inspected possible strategies and then critically review the last two decades works with focus on different nano-scaled electrode modifiers. We organized and described the materials engaged in several categories: Surfactants modifiers, polymeric modifiers, metallic nanomaterials, carbon based nano-modifiers (reduced graphene oxide, multi-walled carbon nanotubes, ordered mesoporous carbon) and a large class of multifarious nano composites-based sensors and biosensors. The main drawbacks and superiorities associated with each array as well as the current trend in the areas is attempted to discuss. Summary of 79 employed electrochemical approaches for analysis of isoniazid and rifampicin has also been presented.

A chitosan grafted mesoporous carbon aerogel for ultra-sensitive voltammetric determination of isoniazid

A screen-printed carbon electrode (SPCE) was modified with chitosan (Chit) supported on carbon aerogel (CA) to obtain an electrochemical sensor for the tuberculosis drug isoniazid (INZ). The interconnected mesoporous structure of Chit/CA provides a large surface area (S_BET = 461 m² g^-1) and good porosity (V_Tot = 0.69 cm³ g^-1). Besides, the modified SPCE displayed enhanced electrocatalytic activity due to the presence of numerous active sites (such as >C=O, -NH-, -NH₂, -OH). Figures of merit include (a) a typical working voltage of 0.28 V (vs. Ag/AgCl), (b) high sensitivity (8.09 μA μM^-1 cm^-2), (c) a wide linear response to INZ (0.01-115 μM) and (d) a low detection limit (8 nM). The modified electrode has successfully been applied to the determination of INZ in spiked serum and urine, and recoveries ranged from 97.8 to 99.8%. Graphical abstract Schematic illustration of preparation and applications of a nanocomposite consisting of chitosan (Chit; CS) supported on carbon aerogel (CA) for electrochemical detection of isoniazid.

Fabrication of a SnO2–graphene nanocomposite based electrode for sensitive monitoring of an anti-tuberculosis agent in human fluids

For electrochemical oxidation of INH on a SnO₂–Gr/GC electrode the voltammetric signal was observed at various electrolyte pH values.

An Enzyme-Induced Novel Biosensor for the Sensitive Electrochemical Determination of Isoniazid

In this present work, a glassy carbon electrode (GCE) was modified primarily with multiwalled carbon nanotubes (MWCNTs) and a composite of MWCNTs and titanium oxide nanoparticles (TiO₂NPs). The enzyme horseradish peroxidase (HRP) was immobilized to enhance the sensing ability of GCE. The proposed biosensor was used for the sensitive determination of isoniazid (INZ) in various pharmaceutical samples. The electrochemical behaviour of the developed MWCNT-TiO₂NPs-HRP-GCE biosensor was studied by using cyclic voltammetry (CV) and differential pulse voltammetric (DPV) techniques. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetry (TGA) and transmission electron microscopy (TEM) techniques were used to characterize the developed sensor. Phosphate buffer solution (PBS) with pH 7 was used as supporting electrolyte in the present investigation. The cyclic voltammetric results revealed that the increment of anodic peak currents for the enzyme-induced sensor was almost 8-fold greater than that of a bare GCE. The DPV technique exhibited good limit of detection and limit of quantification values, viz., 0.0335 μM and 0.1118 μM, respectively. Moreover, the developed sensor showed long-lasting stability and repeatability without any interferents. This strongly indicates that the fabricated sensor shows outstanding electrochemical performance towards INZ, with excellent selectivity and sensitivity. The developed sensor was successfully applied to pharmaceutical samples and gave good percentages of recoveries.

Development of a Nafion/MWCNT-SPCE-Based Portable Sensor for the Voltammetric Analysis of the Anti-Tuberculosis Drug Ethambutol

Herein we describe the development, characterization and application of an electrochemical sensor based on the use of Nafion/MWCNT-modified screen-printed carbon electrodes (SPCEs) for the voltammetric detection of the anti-tuberculosis (anti-TB) drug ethambutol (ETB). The electrochemical behaviour of the drug at the surface of the developed Nafion/MWCNT-SPCEs was studied through cyclic voltammetry (CV) and square wave voltammetry (SWV) techniques. Electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) were employed to characterize the modified surface of the electrodes. Results showed that, compared to both unmodified and MWCNTs-modified SPCEs, negatively charged Nafion/MWCNT-SPCEs remarkably enhanced the electrochemical sensitivity and selectivity for ETB due to the synergistic effect of the electrostatic interaction between cationic ETB molecules and negatively charged Nafion polymer and the inherent electrocatalytic properties of both MWCNTs and Nafion. Nafion/MWCNT-SPCEs provided excellent biocompatibility, good electrical conductivity, low electrochemical interferences and a high signal-to-noise ratio, providing excellent performance towards ETB quantification in microvolumes of human urine and human blood serum samples. The outcomes of this paper confirm that the Nafion/MWCNT-SPCE-based device could be a potential candidate for the development of a low-cost, yet reliable and efficient electrochemical portable sensor for the low-level detection of this antimycobacterial drug in biological samples.

From mercury to nanosensors: Past, present and the future perspective of electrochemistry in pharmaceutical and biomedical analysis

Polarography was the first developed automated method of voltage-controlled electrolysis with dropping mercury electrode (DME). Then, hanging mercury drop and static mercury drop electrodes were added as an alternative indicator electrode. In this way, polarography turned formally into voltammetry with mercury electrodes in the electroreduction way. Solid electrodes such as noble metal and carbon based electrodes can be used for the investigation of the compounds for both oxidation and reduction directions, which is called voltammetry. The voltammetric and polarographic techniques are more sensitive, reproducible, and easily used electroanalytical methods that can be alternative to more frequently used separation and spectrometric methods. Furthermore, in some cases there is a relationship between voltammetry and pharmaceutical samples, and the knowledge of the mechanism of their electrode reactions can give a useful clue in elucidation of the mechanism of their interaction with living cells. The voltammetric and polarographic analysis of drugs in pharmaceutical preparations are by far the most common use of electrochemistry for analytical pharmaceutical problems. Recent trends and challenges in the electrochemical methods for the detection of DNA hybridization and pathogens are available. Low cost, small sample requirement and possibility of miniaturization justifies their increasing development.