Rapid determination of uracil in biological fluids at mercury thin film electrode for early detection of potential 5-fluorouracil toxicity due to dihydropyrimidine dehydrogenase deficiency.

Determination of plasma uracil was reported as a method for evaluation of Dihydropyrimidine dehydrogenase (DPD) activity that is highly demanded to ensure the safe administration of 5-fluorouracil (5-FU)-based therapies to cancer patients. This work reports the development of a simple electroanalytical method based on adsorptive stripping square wave voltammetry (AdSWV) at mercury film-coated glassy carbon electrode (MF/GCE) for the highly sensitive determination of uracil in biological fluids that can be used for diagnosis of decreased DPD activity. Due to the formation of the HgII-Uracil complex at the electrode surface, the accuracy of the measurement was not affected by the complicated matrices in biological fluids including human serum, plasma, and urine. The high sensitivity of the developed method results in a low limit of detection (≈1.3 nM) in human plasma samples, falling below the practical cut-off level of 15 ng mL-1 (≈0.14 µM). This threshold concentration is crucial for predicting 5-FU toxicity, as reported in buffer, and ≤1.15% in biological samples), and accuracy (recovery percentage close to 100%).

A Strep-tag Imprinted Polymer Platform for Heterogenous Bio(electro)catalysis.

Molecularly imprinted polymers (MIPs) are artificial receptors equipped with selective recognition sites for target molecules. One of the most promising-strategies for protein MIPs relies on the exploitation of short surface-exposed protein fragments, termed epitopes, as templates to imprint binding sites in a polymer scaffold for a desired protein. However, the lack of high-resolution structural data of flexible surface-exposed regions challenges the selection of suitable epitopes. Here, we addressed this drawback by developing a polyscopoletin-based MIP that recognizes recombinant proteins via the widely used Strep-tag II affinity peptide. Electrochemistry, surface-sensitive spectroscopy, and molecular dynamics simulations were employed to ensure an utmost control of the Strep-MIP electrosynthesis. The functionality of this novel platform was verified with two Strep-tag labeled enzymes: an O2-tolerant [NiFe]-hydrogenase, and an alkaline phosphatase. The enzymes preserved their biocatalytic activities after multiple utilization confirming the efficiency of Strep-MIP as a general biocompatible platform to confine recombinant proteins for exploitation in biotechnology.

Recent Advancements in the Analyses of Natural Products.

Since ancient times, medicinal plants and their active ingredients have played a key role in treating a wide array of ailments. Notably, in recent years, there has been a burgeoning interest in treatments using products derived from natural sources, and some have been studied as clinical treatments for a variety of disorders. The use of natural products to treat illness has gained increasing scientific and public interest. Not only to ensure quality control but also to verify their efficacy as active ingredients in various pharmaceutical formulations, the evaluation of natural products is of paramount importance. In this field, analytical methods like spectroscopy, electrophoresis, and chromatography are essential and are constantly being improved upon. Chromatographic techniques are essential for determining the quality and authenticity of natural products. Moreover, strict adherence to internationally recognized norms in validating analytical procedures guarantees the accuracy and dependability of results. Continual research initiatives are essential for tackling issues like adulteration and enhancing customer trust in natural products. This review navigates through the complex field of quality control methodologies and analytical techniques applied in evaluating plant-derived sources, which are generally used as natural products, and focuses on the analysis of Hypericum, Curcuma, and Cannabis species.

Nanostructured Metal Oxide-Based Electrochemical Biosensors in Medical Diagnosis.

Nanostructured metal oxides (NMOs) provide electrical properties such as high surface-to-volume ratio, reaction activity, and good adsorption strength. Furthermore, they serve as a conductive substrate for the immobilization of biomolecules, exhibiting notable biological activity. Capitalizing on these characteristics, they find utility in the development of various electrochemical biosensing devices, elevating the sensitivity and selectivity of such diagnostic platforms. In this review, different types of NMOs, including zinc oxide (ZnO), titanium dioxide (TiO2), iron (II, III) oxide (Fe3O4), nickel oxide (NiO), and copper oxide (CuO); their synthesis methods; and how they can be integrated into biosensors used for medical diagnosis are examined. It also includes a detailed table for the last 10 years covering the morphologies, analysis techniques, analytes, and analytical performances of electrochemical biosensors developed for medical diagnosis.

Application of Carbon-based Nano Adsorbents in the Extraction of Amphetamines from Urine Samples.

Amphetamines, as psychoactive drugs, are extensively abused in society and cause serious mental and physical disorders among young people. Furthermore, the extremely euphoric and excited sense of stimulant consumption leads to dramatic social problems. Determination of various analytes and related metabolites in the complex biological matrices at trace levels has made sample preparation an indispensable part of forensic sciences. According to the problems above, providing high sensitivity, solving some analytical problems like matrix effects in LCMS-MS, and needing a cleaner extract are remarkable aspects of novel sample preparation methods in drug analysis. Application of nanotechnology and carbon-based nanocomposites seems to bring the above properties in developed and novel sample preparation methods. This review will try to provide an overview of different carbonic nano adsorbents used in sample preparation methods of amphetamines and discuss their superiority over the other nanomaterials.

Magnetic Nanomaterials for Sample Preparation of Disease-related Biomarkers.

Measuring clinically relevant biomarkers is critical for disease screening, diagnosis, and therapeutic monitoring. However, analyzing trace biomarkers in complex biological fluids remains challenging. Magnetic solid phase extraction (MSPE) has recently emerged as a promising sample preparation approach due to its simplicity, efficiency, and ability to selectively isolate biomarkers. Databases, including PubMed, Web of Science, and Scopus, were systematically searched for studies on MSPE for clinical biomarkers. Key findings on nanomaterial synthesis strategies, surface modifications, and applications in biomarker isolation were synthesized. Recent research demonstrates magnetic nanoparticles with tailored surface chemistry can selectively extract biomarkers like cancer antigens, neurotransmitters, and pharmaceuticals from matrices such as plasma, urine, and serum. MSPE enables clinically relevant limits of detection, high recovery, and purification in a rapid and simple workflow. This technique shows significant potential to improve clinical diagnostics. Further research on novel magnetic materials and surface functionalization is warranted. This review provides insights for researchers aiming to develop MSPE methods for sensitive and selective analysis of clinical biomarkers.

Imprinted Polymers on the Route to Plastibodies for Biomacromolecules (MIPs), Viruses (VIPs), and Cells (CIPs).

Around 30% of the scientific papers published on imprinted polymers describe the recognition of proteins, nucleic acids, viruses, and cells. The straightforward synthesis from only one up to six functional monomers and the simple integration into a sensor are significant advantages as compared with enzymes or antibodies. Furthermore, they can be synthesized against toxic substances and structures of low immunogenicity and allow multi-analyte measurements via multi-template synthesis. The affinity is sufficiently high for protein biomarkers, DNA, viruses, and cells. However, the cross-reactivity of highly abundant proteins is still a challenge.

Enhancing electrochemical sensing through the use of functionalized graphene composites as nanozymes.

Graphene-based nanozymes possess inherent nanomaterial properties that offer not only a simple substitute for enzymes but also a versatile platform capable of bonding with complex biochemical environments. The current review discusses the replacement of enzymes in developing biosensors with nanozymes. Functionalization of graphene-based materials with various nanoparticles can enhance their nanozymatic properties. Graphene oxide functionalization has been shown to yield graphene-based nanozymes that closely mimic several natural enzymes. This review provides an overview of the classification, current state-of-the-art development, synthesis routes, and types of functionalized graphene-based nanozymes for the design of electrochemical sensors. Furthermore, it includes a summary of the application of functionalized graphene-based nanozymes for constructing electrochemical sensors for pollutants, drugs, and various water and food samples. Challenges related to nanozymes as electrocatalytic materials are discussed, along with potential solutions and approaches for addressing these shortcomings.

Novel Approaches to Enzyme-Based Electrochemical Nanobiosensors.

Electrochemistry is a genuinely interdisciplinary science that may be used in various physical, chemical, and biological domains. Moreover, using biosensors to quantify biological or biochemical processes is critical in medical, biological, and biotechnological applications. Nowadays, there are several electrochemical biosensors for various healthcare applications, such as for the determination of glucose, lactate, catecholamines, nucleic acid, uric acid, and so on. Enzyme-based analytical techniques rely on detecting the co-substrate or, more precisely, the products of a catalyzed reaction. The glucose oxidase enzyme is generally used in enzyme-based biosensors to measure glucose in tears, blood, etc. Moreover, among all nanomaterials, carbon-based nanomaterials have generally been utilized thanks to the unique properties of carbon. The sensitivity can be up to pM levels using enzyme-based nanobiosensor, and these sensors are very selective, as all enzymes are specific for their substrates. Furthermore, enzyme-based biosensors frequently have fast reaction times, allowing for real-time monitoring and analyses. These biosensors, however, have several drawbacks. Changes in temperature, pH, and other environmental factors can influence the stability and activity of the enzymes, affecting the reliability and repeatability of the readings. Additionally, the cost of the enzymes and their immobilization onto appropriate transducer surfaces might be prohibitively expensive, impeding the large-scale commercialization and widespread use of biosensors. This review discusses the design, detection, and immobilization techniques for enzyme-based electrochemical nanobiosensors, and recent applications in enzyme-based electrochemical studies are evaluated and tabulated.

Characterization of Climbazole-Bovine serum albumin interaction by experimental and in silico approaches.

Interactive association of an antifungal drug, climbazole (CBZ) with the carrier protein in bovine circulation, bovine serum albumin (BSA) was explored by fluorescence and absorption spectroscopy along with in silico techniques. The fluorescence and absorption spectral alterations of the protein upon addition of CBZ affirmed the complex foration between CBZ and BSA. The inverse temperature dependence behaviour of the KSV values as well as the hyperchromic result of the protein's absorption signals characterized CBZ-triggered quenching of BSA fluorescence as the static quenching. A weak binding affinity (Ka = 3.12-1.90-× 103 M-1) was reported towards the CBZ-BSA association process. Interpretation of thermodynamic data (entropy change = +14.68 J mol-1 K-1 and enthalpy change = -15.07 kJ mol-1) and in silico analyses anticipated that hydrophobic forces, van der Waals forces and hydrogen bonds were the key intermolecular forces in the complex stabilization. Inclusion of CBZ to BSA produced microenvironmental perturbations around Tyr and Trp residues, and also significantly defended temperature-induced destabilization of BSA. The binding locus of CBZ was detected in the proximity of Sudlow's sites I (subdomain IIA) and II (subdomain IIIA) of BSA, exhibiting greater preference towards site II, as revealed by competitive site-marker displacement investigations and in silico analysis. The stability of the CBZ-BSA complex was further validated by the molecular dynamics simulation assessments.

Elucidating the interaction of antidepressant drug paroxetine with ct-dsDNA: A comparative study by electrochemical, spectroscopic, and molecular docking approaches.

This study is designed to investigate the interaction of phenylpiperidine derivative drug paroxetine, which is an effective serotonin reuptake inhibitor and biomolecules through electrochemical, fluorescence spectroscopy, and molecular docking methods. The interaction between paroxetine and biomolecules was investigated by differential pulse voltammetry according to the decrease in deoxyguanosine anodic oxidation signal of double-stranded calf thymus DNA. Fluorescence spectroscopy studies were performed by titrating paroxetine against double-stranded calf thymus DNA solution at four different temperatures. The fluorescent results showed that paroxetine had a great affinity to bind with double-stranded calf thymus DNA. Interaction studies demonstrate that paroxetine binds to double-stranded calf thymus DNA via intercalation binding mode, and the binding constant values ​​were calculated as 7.24 × 104 M-1 and 1.52 × 104 M-1 at 25 °C, based on voltammetric and spectroscopic results, respectively. Moreover, with the aim of elucidating the interaction mechanism between paroxetine and double-stranded calf thymus DNA, electrochemical and fluorescence spectroscopy studies along with molecular docking analysis were made.

An Efficient, Simultaneous Electrochemical Assay of Rosuvastatin and Ezetimibe from Human Urine and Serum Samples.

The drug combination of rosuvastatin (ROS) and ezetimibe (EZE) is used to treat hypercholesterolemia. In this work, a simultaneous electrochemical examination of ROS and EZE was conducted for the first time. The electrochemical determination of ROS and EZE was carried out using adsorptive stripping differential pulse voltammetry (AdSDPV) on a glassy carbon electrode (GCE) in 0.1 M H2SO4. The effects of the pH, scan rate, deposition potential, and time on the detection of ROS and EZE were analyzed. Under optimum conditions, the developed sensor exhibited a linear response between 1.0 × 10-6 M and 2.5 × 10-5 M for EZE and 5.0 × 10-6 M, and 1.25 × 10-5 M for ROS. The detection limits for ROS and EZE were 3.0 × 10-7 M and 2.0 × 10-6 M, respectively. The developed sensor was validated in terms of linear range, accuracy, precision, the limit of determination (LOD), and the limit of quantification (LOQ), and it was evaluated according to ICH Guidelines and USP criteria. The proposed method was also used to determine ROS and EZE in human urine and serum samples, which are reported in terms of recovery studies.

Electrochemical biosensor based on three components random conjugated polymer with fullerene (C60).

Herein, a conjugated polymer and fullerene bearing architecture-based electrochemical Tyrosinase (Tyr) enzyme inhibition biosensor for indomethacin (INDO) drug active compound has been developed. For this purpose, three moieties of benzoxadiazole, thienopyrroledione, and benzodithiophene containing conjugated polymer; poly[BDT-alt-(TP;BO)] was used as a transducer modifier together with fullerene for catechol detection. The specific combination of these materials is considered an effective way to fabricate highly sensitive and fast response catechol biosensors for the first time. Electrochemical and surface characteristics of the modified electrodes were obtained by cyclic voltammetry, electrochemical impedance spectroscopy, scanning electron microscopy, and atomic force microscopy. The effect of the parameters during chronoamperometric measurements on the biosensor response was also studied. Using optimized conditions, biosensing of catechol was achieved between 0.5 and 62.5 µM with a limit of the detection 0.11 µM. Tyr inhibition was followed with INDO drug active compound and it was found that INDO has a mixed type characteristic of enzyme kinetics with an I50 value of 15.11 µM.

Molecularly Imprinted Polymer-Based Sensors for SARS-CoV-2: Where Are We Now?

Since the first reported case of COVID-19 in 2019 in China and the official declaration from the World Health Organization in March 2021 as a pandemic, fast and accurate diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has played a major role worldwide. For this reason, various methods have been developed, comprising reverse transcriptase-polymerase chain reaction (RT-PCR), immunoassays, clustered regularly interspaced short palindromic repeats (CRISPR), reverse transcription loop-mediated isothermal amplification (RT-LAMP), and bio(mimetic)sensors. Among the developed methods, RT-PCR is so far the gold standard. Herein, we give an overview of the MIP-based sensors utilized since the beginning of the pandemic.

Evaluation of the Interaction of Cinacalcet with Calf Thymus dsDNA: Use of Electrochemical, Spectrofluorimetric, and Molecular Docking Methods.

The binding of drugs to DNA plays a critical role in new drug discovery and is important for designing better drugs. In this study, the interaction and binding mode of calf-thymus double-stranded deoxyribonucleic acid (ct-dsDNA) with cinacalcet (CIN) from the calcimimetic drug that mimics the action of calcium on tissues group were investigated. The interaction of CIN with ct-dsDNA was observed by the differential pulse voltammetry (DPV) technique by following the decrease in electrochemical oxidation signals to deoxyguanosine and adenosine. A competitive study was performed on an indicator, methylene blue, to investigate the interaction of the drug with ct-dsDNA by fluorescence spectroscopy. Interaction studies have shown that the binding mode for the interaction of CIN with ct-dsDNA could be groove-binding. According to the results obtained, the binding constant values were found to be 6.30 × 104 M-1 and 3.16 × 105 M-1, respectively, at 25 °C as obtained from the cyclic voltammetry (CV) and spectroscopic techniques. Possible molecular interactions of CIN with dsDNA were explored via molecular docking experiments. The docked structure indicated that CIN could fit well into the minor groove of the DNA through H-bonding and π-π stacking contact with CIN.

The Interaction between DNA and Three Intercalating Anthracyclines Using Electrochemical DNA Nanobiosensor Based on Metal Nanoparticles Modified Screen-Printed Electrode.

The screen-printed electrodes have gained increasing importance due to their advantages, such as robustness, portability, and easy handling. The manuscript presents the investigation of the interaction between double-strand deoxyribonucleic acid (dsDNA) and three anthracyclines: epirubicin (EPI), idarubicin (IDA), and doxorubicin (DOX) by differential pulse voltammetry on metal nanoparticles modified by screen-printed electrodes. In order to investigate the interaction, the voltammetric signals of dsDNA electroactive bases were used as an indicator. The effect of various metal nanomaterials on the signals of guanine and adenine was evaluated. Moreover, dsDNA/PtNPs/AgNPs/SPE (platinum nanoparticles/silver nanoparticles/screen-printed electrodes) was designed for anthracyclines-dsDNA interaction studies since the layer-by-layer modification strategy of metal nanoparticles increases the surface area. Using the signal of multi-layer calf thymus (ct)-dsDNA, the within-day reproducibility results (RSD%) for guanine and adenine peak currents were found as 0.58% and 0.73%, respectively, and the between-day reproducibility results (RSD%) for guanine and adenine peak currents were found as 1.04% and 1.26%, respectively. The effect of binding time and concentration of three anthracyclines on voltammetric signals of dsDNA bases were also evaluated. The response was examined in the range of 0.3-1.3 ppm EPI, 0.1-1.0 ppm IDA and DOX concentration on dsDNA/PtNPs/AgNPs/SPE. Electrochemical studies proposed that the interaction mechanism between three anthracyclines and dsDNA was an intercalation mode.

Simultaneous Determination of Hydrochlorothiazide and Irbesartan from Pharmaceutical Dosage Forms with RP-HPLC.

OBJECTIVES: In this work, a simple and rapid liquid chromatographic method for the simultaneous determination of irbesartan (IRBE) and hydrochlorothiazide (HCT) was developed and validated by reverse phase high performance liquid chromatography (RP-HPLC). MATERIALS AND METHODS: Experimental conditions such as different buffer solutions, various pH values, temperature, composition of the mobile phase, and the effect of flow rate were optimized. RESULTS: The developed RP-HPLC method for these antihypertensive agents was wholly validated and IRBE was detected in the linear range of 0.1-25 µg mL-1 and HCT was detected in the linear range of 0.25-25 µg mL-1. Moreover, the suggested chromatographic technique was successfully applied for the determination of the drugs in human serum and pharmaceutical dosage forms with limit of detection values of 0.008 µg mL-1 for IRBE and 0.012 µg mL-1 for HCT. CONCLUSION: The proposed rapid analysis method of these antihypertensive drugs can be easily used and applied by pharmaceutical companies for which the analysis time is important.

Carbon-based ruthenium nanomaterial-based electroanalytical sensors for the detection of anticancer drug Idarubicin.

In this work, a novel nanosensing platform was suggested based on ruthenium for the sensitive determination of Idarubicin anticancer drugs. Ruthenium/Vulcan carbon-based nanoparticles were synthesized ultrasonication method and then characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The mean particle size of the nanoparticles calculated by the TEM analysis was found to be 1.98 nm ± 0.29 nm, and the Ru nanoparticles were mostly dispersed on the support material. Glassy carbon electrode (GCE) surface was modified with Ruthenium/Vulcan carbon-based nanomaterials (Ru@VC), and characterization of the nanosensor was performed using electrochemical impedance spectroscopy and cyclic voltammetry. The limit of detection (LOD) and limit of quantification (LOQ) values were found as 9.25 × 10-9 M and 2.8 × 10-8 M in buffer samples. To demonstrate the applicability and validity of developed nanosensor, it was used for the determination of Idarubicin in Idamen® IV (10 mg/10 mL vial) and human serum sample. The results of recovery studies showed that the Ru@VC/GCE nanosensor was free from excipient interferences in the dosage forms of injection, and it can be successfully applied to biological samples.