DNA Langmuir–Blodgett modified glassy carbon electrode as voltammetric sensor for determinate of methotrexate

Electrochemistry as a Powerful Tool for Investigations of Antineoplastic Agents: A Comprehensive Review

Cancer is most frequently treated with antineoplastic agents (ANAs) that are hazardous to patients undergoing chemotherapy and the healthcare workers who handle ANAs in the course of their duties. All aspects related to hazardous oncological drugs illustrate that the monitoring of ANAs is essential to minimize the risks associated with these drugs. Among all analytical techniques used to test ANAs, electrochemistry holds an important position. This review, for the first time, comprehensively describes the progress done in electrochemistry of ANAs by means of a variety of bare or modified (bio)sensors over the last four decades (in the period of 1982-2021). Attention is paid not only to the development of electrochemical sensing protocols of ANAs in various biological, environmental, and pharmaceutical matrices but also to achievements of electrochemical techniques in the examination of the interactions of ANAs with deoxyribonucleic acid (DNA), carcinogenic cells, biomimetic membranes, peptides, and enzymes. Other aspects, including the enantiopurity studies, differentiation between single-stranded and double-stranded DNA without using any label or tag, studies on ANAs degradation, and their pharmacokinetics, by means of electrochemical techniques are also commented. Finally, concluding remarks that underline the existence of a significant niche for the basic electrochemical research that should be filled in the future are presented.

Electrochemical DNA biosensors developed for the monitoring of biointeractions with drugs: a review

The interaction of drugs with DNA is important for the discovery of novel drug molecules and for understanding the therapeutic effects of drugs as well as the monitoring of side effects. For this reason, many studies have been carried out to investigate the interactions of drugs with nucleic acids. In recent years, a large number of studies have been performed to electrochemically detect drug-DNA interactions. The fast, sensitive, and accurate results of electrochemical techniques have resulted in a leading role for their implementation in this field. By means of electrochemical techniques, it is possible not only to demonstrate drug-DNA interactions but also to quantitatively analyze drugs. In this context, electrochemical biosensors for drug-DNA interactions have been examined under different headings including anticancer, antiviral, antibiotic, and central nervous system drugs as well as DNA-targeted drugs. An overview of the studies related to electrochemical DNA biosensors developed for the detection of drug-DNA interactions that were reported in the last two decades in the literature is presented herein along with their applications and they are discussed together with their future perspectives.

Sensitive and Selective Electrochemical Detection of Epirubicin as Anticancer Drug Based on Nickel Ferrite Decorated with Gold Nanoparticles

The accurate and precise monitoring of epirubicin (EPR), one of the most widely used anticancer drugs, is significant for human and environmental health. In this context, we developed a highly sensitive electrochemical electrode for EPR detection based on nickel ferrite decorated with gold nanoparticles (Au@NiFe₂O₄) on the screen-printed electrode (SPE). Various spectral characteristic methods such as Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV-Vis), energy-dispersive X-ray spectroscopy (EDX) and electrochemical impedance spectroscopy (EIS) were used to investigate the surface morphology and structure of the synthesized Au@NiFe₂O₄ nanocomposite. The novel decorated electrode exhibited a high electrocatalytic activity toward the electrooxidation of EPR, and a nanomolar limit of detection (5.3 nM) was estimated using differential pulse voltammetry (DPV) with linear concentration ranges from 0.01 to 0.7 and 0.7 to 3.6 µM. The stability, selectivity, repeatability reproducibility and reusability, with a very low electrode response detection limit, make it very appropriate for determining trace amounts of EPR in pharmaceutical and clinical preparations.

Ultrasensitive fluorescence detection of antitumor drug methotrexate based on a terbium-doped silica dendritic probe

A novel strategy was developed for the detection of methotrexate (MTX) via the quenching effect of MTX on the fluorescence intensity of terbium-doped dendritic silica particles (Tb@KCC-1). The fluorescence intensity of Tb@KCC-1 can be effectively quenched by MTX at 546 nm under an excitation wavelength of 233 nm. The quenched fluorescence is proportional to the amount of MTX in both plasma and exhaled breath condensate (EBC) samples. Under the optimal conditions, the linear dynamic ranges of the developed method were 44 nM to 2.2 μM for EBC, 44 nM to 0.22 μM and 0.22-2.2 μM for plasma samples. The limit of detection (LOD) and limit of quantification (LOQ) in both plasma and EBC media are 35 and 116 nM, respectively. The developed method has the benefits of fast analysis time, simple approach, high specificity, and sensitivity for the detection of MTX in both media. This nanoprobe has been successfully utilized for the quantification of MTX in patients' plasma and spiked EBC samples, proving the applicability of the nanoprobe for MTX detection in real samples.

Lipid-matrix effects on tyrosinase immobilization in Langmuir and Langmuir-Blodgett films

The immobilization of the enzyme tyrosinase (Tyr) in lipid matrices can be explored to produce biosensors for detecting polyphenols, which is relevant for the food industry. Herein, we shall demonstrate the importance of the lipid composition to immobilize the enzyme tyrosinase in Langmuir-Blodgett (LB) films. Tyr could be incorporated into Langmuir monolayers of arachidic acid (AA), 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1,2-dipalmitoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (sodium salt) (DPPG), having as the main effect an expansion in the monolayers. Results from polarization-modulated infrared reflection-absorption spectroscopy (PM-IRRAS) pointed to electrostatic interactions between the charged residues of Try and the lipid headgroups, in addition to changes in the order of lipid chains. The interaction between Tyr and DPPC in Langmuir monolayers can be correlated with the superior performance of DPPC/Tyr LB films used as biosensors to detect catechol by cyclic voltammetry. The molecular-level interactions assessed via PM-IRRAS are therefore believed to drive an immobilization process for Tyr in the lipid LB matrix and may serve as a general criterion to identify matrices that preserve enzyme activity.

Analytical methodologies for determination of methotrexate and its metabolites in pharmaceutical, biological and environmental samples

Methotrexate (MTX) is a folate antagonist drug used for several diseases, such as cancers, various malignancies, rheumatoid arthritis (RA) and inflammatory bowel disease. Due to its structural features, including the presence of two carboxylic acid groups and its low native fluorescence, there are some challenges to develop analytical methods for its determination. MTX is metabolized to 7-hydroxymethotrexate (7-OH-MTX), 2,4-diamino-N10-methylpteroic acid (DAMPA), and the active MTX polyglutamates (MTXPGs) in the liver, intestine, and red blood cells (RBCs), respectively. Additionally, the drug has a narrow therapeutic range; hence, its therapeutic drug monitoring (TDM) is necessary to regulate the pharmacokinetics of the drug and to decrease the risk of toxicity. Due to environmental toxicity of MTX; its sensitive, fast and low cost determination in workplace environments is of great interest. A large number of methodologies including high performance liquid chromatography equipped with UV-visible, fluorescence, or electrochemical detection, liquid chromatography-mass spectroscopy, capillary electrophoresis, UV-visible spectrophotometry, and electrochemical methods have been developed for the quantitation of MTX and its metabolites in pharmaceutical, biological, and environmental samples. This paper will attempt to review several published methodologies and the instrumental conditions, which have been applied to measure MTX and its metabolites within the last decade.

Ultrasound-induced radicals initiated the formation of inorganic-organic Pr2O3/polystyrene hybrid composite for electro-oxidative determination of chemotherapeutic drug methotrexate

To dates, the facile synthesis of inorganic-coated organic polymer composite has received greater attention in the order of research fields including advanced materials and electrochemical analysis owing to the complementary or synergistic effects. In this context, Pr₂O₃ and Pr₂O₃ coated polystyrene (Pr₂O₃/PS) inorganic-organic colloidal composite were prepared via ultrasound-induced radicals initiated precipitation and dispersion polymerization methods. The synthesized Pr₂O₃/PS composite was systematically studied by FE-SEM, TEM, EDX, FT-IR, XRD, and XPS analysis. This composite modified glassy carbon electrode (Pr₂O₃/PS GCE) was utilized to construct a novel electrochemical sensor for the detection assay of chemotherapy agent methotrexate (MTA). Under optimal condition, the designed sensor showed outstanding performance for MTA trace level detection over the linear concentration range of 0.01-236 µM with a detection limit of 0.8 nM for MTA. Furthermore, the prepared sensor accomplished excellent stability and relevant reproducibility, in addition to reliable practical assay in real human blood serum and urine samples. Besides, the possible MTA sensing mechanism of Pr₂O₃/PS GCE has been deliberated in detail. Our finding suggested that the developed Pr₂O₃/PS composite might be a favorable material for the fabrication of the high-performance electrochemical sensor.

Determination of methotrexate in spiked human blood serum using multi-frequency electrochemical immittance spectroscopy and multivariate data analysis

This article describes an attempt to develop a sensor based on multi-frequency immittance spectroscopy for the determination of methotrexate (MTX) in blood serum using gold electrodes modified with antibodies. The attachment of antibodies was monitored with electrochemical immittance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS). The EIS measurements of MTX resulted in a data matrix of size 39 × 55. The data were analysed using multivariate data analysis and showed a concentration dependence and time dependence that could be separated. This allowed the calculation of a multivariate calibration model. The model showed good linear behavior on a logarithmic scale offering a detection limit of 5 × 10^-12 mol L^-1.

Detection of methotrexate in a flow system using electrochemical impedance spectroscopy and multivariate data analysis

Methotrexate (MTX), a common pharmaceutical drug in cancer therapy and treatment of rheumatic diseases, is known to cause severe adverse side effects at high dose. As the side effect may be life threatening, there is an urgent need for a continuous, bed-side monitoring of the nominal MTX serum level in a patient while the chemical is being administered. This article describes a detection of MTX using a flow system that consists two modified gold electrodes. Interaction of MTX with the antibodies fixed on the electrode surface is detected by electrochemical impedance spectroscopy and evaluated using singular value decomposition (SVD). The key finding of this work is that the change in the electrode capacitance is found to be quantitative with respect to the concentration of MTX. Moreover a calibration curve constructed using the principal component regression method has a linear range of six orders of magnitude and a detection limit of 1.65 × 10(-10) M.

Flower-like ZnO nanostructure based electrochemical DNA biosensor for bacterial meningitis detection

Zinc oxide (ZnO) nanostructures possessing flower-like morphology have been synthesised onto platinized silicon substrate by simple and economical hydrothermal method. The interaction of physically immobilized single stranded thiolated DNA (ss th-DNA) probe of N. meningitides onto the nanostructured ZnO (ZNF) matrix surface have been investigated using cyclic voltammetry (CV) and electrochemical impeadance spectroscopy (EIS). The electrochemical sensing response behaviour of the DNA bioelectrode (ss th-DNA/ZNF/Pt/Si) has been studied by both differential pulse voltammetric (DPV) as well as impedimetric techniques. The fabricated DNA biosensor can quantify wide range of the complementary target ss th-DNA in the range 5-240 ng μl(-1) with good linearity (R=0.98), high sensitivity (168.64 μA ng(-1) μl cm(-2)) and low detection limit of about 5 ng μl(-1). Results emphasise that the fabricated flower-like ZnO nanostructures offer a useful platform for the immobilization of DNA molecules and could be exploited for efficient detection of complementary target single stranded DNA corresponding to N. meningitides.

Electrochemical detection of dihydromyricetin using a DNA immobilized ethylenediamine/polyglutamic modified electrode

A novel voltammetric sensor, based on DNA immobilized on the surface of an ethylenediamine/polyglutamic (En/PGA) modified glassy carbon electrode (GCE), was constructed and used for determination of dihydromyricetin (DMY). The electrochemical behaviour of DMY at this sensor was investigated in pH 3.6 NaAc-HAc buffer solutions by cyclic voltammetry (CV) and differential pulse anodic voltammetry (DPV). The oxidation of DMY is an adsorption-controlled irreversible process. The oxidation mechanism was proposed and discussed. It was found that the modified electrode exhibited a linear voltammetric response for DMY in the range of 4.0 × 10(-8) mol L(-1) to 2 × 10(-6) mol L(-1), with a detection limit of 2 × 10(-8) mol L(-1). The method was also applied successfully to detect DMY in an ampelopsis sample with satisfactory results.