Applications of electrochemical techniques for determination of anticoagulant drug (Rivaroxaban) in real samples

A disposable homemade screen printed electrode for famotidine analysis using a computer-designed molecularly imprinted polymer based on the MWCNT-Fe3O4 nanocomposite in simulated real samples

A home-made screen printed electrode (SPE) was designed with a magnetic multi-walled carbon nanotube composite (MWCNT-Fe3O4) and a molecularly imprinted polymer (MIP) for sensitive and selective electrochemical analysis of famotidine (FAM). The SPE was fabricated using non-commercial conductive inks such as carbon and silver inks. The electrodes were printed by a painting technique on polyvinyl chloride (PVC) sheets as a substrate. To optimize the composition of the carbon ink, a mixture design methodology was employed. A computational approach was used to select the functional monomer. The imprinted layer was synthesized by electropolymerization of FAM (template) and pyrrole (PY) (monomer) using cyclic voltammetry (CV) on the working electrode surface modified with the MWCNT-Fe3O4 nanocomposite. Differential pulse voltammetry (DPV) was applied to characterize the template removal and rebinding processes. The Plackett-Burman design (PBD) and central composite design (CCD) investigated the effect of parameters on the MIP/MWCNT-Fe3O4/SPE performance. The sensor exhibited a linear dynamic range of 1-1000 μM (R2 = 0.9919) with a limit of detection (LOD) of 0.027 μM (3sb, n = 3). It demonstrated good repeatability and reproducibility, with relative standard deviations (RSD) of 3.6 and 4.2, respectively. This disposable and cost-effective sensor successfully detected FAM in simulated real samples and correlated well with high-performance liquid chromatography (HPLC) results.

Integration of 3D printed Mg2+ potentiometric sensors into microfluidic devices for bioanalysis

Electrochemical sensors provide an affordable and reliable approach towards the detection and monitoring of important biological species ranging from simple ions to complex biomolecules. The ability to miniaturize electrochemical sensors, coupled with their affordability and simple equipment requirements for signal readout, permits the use of these sensors at the point-of-care where analysis using non-invasively obtainable biofluids is receiving growing interest by the research community. This paper describes the design, fabrication, and integration of a 3D printed Mg2+ potentiometric sensor into a 3D printed microfluidic device for the quantification of Mg2+ in low-sample volume biological fluids. The sensor employs a functionalized 3D printable photocurable methacrylate-based ion-selective membrane affixed to a carbon-mesh/epoxy solid-contact transducer for the selective determination of Mg2+ in sweat, saliva and urine. The 3D printed Mg2+ ion-selective electrode (3Dp-Mg2+-ISE) provided a Nernstian response of 27.5 mV per decade with a linear range of 10 mM to 39 μM, covering the normal physiological and clinically relevant levels of Mg2+ in biofluids. 3Dp-Mg2+-ISEs selectively measure Mg2+ over other biologically present cations - sodium, potassium, calcium, ammonium - as well as provide high stability in the analytical signal with a drift of just 13 μV h-1 over 10 hours. Comparison with poly(vinylchloride)-based Mg2+-ISEs showed distinct advantages to the use of 3Dp-Mg2+-ISEs, with respect to stability, resilience towards biofouling and importantly providing a streamlined and rapid approach towards mass production of selective and reliable sensors. The miniaturization capabilities of 3D printing coupled with the benefits of microfluidic analysis (i.e., low sample volumes, minimal reagent consumption, automation of multiple assays, etc.), provides exciting opportunities for the realization of the next-generation of point-of-care diagnostic devices.

A novel fluorescent probe based imprinted polymer-coated magnetite for the detection of imatinib leukemia anti-cancer drug traces in human plasma samples

Myeloid leukemia is a chronic cancer, which associated with abnormal BCR-ABL tyrosine kinase activity. Imatinib (IMB) acts as a tyrosine kinase inhibitor and averts tumor growth in cancer cells by controlling cell division, so it is urgent to develop an effective assay to detect and monitor its IMB concentration. Therefore, an innovative fluorescent biomimetic sensor is a promising sensing material that constructed for the efficient recognition of IMB and displays excellent selectivity and sensitivity stemming from molecularly imprinted polymer@Fe3O4 (MIP@Fe3O4). The detection strategy depends on the recognition of IMB molecules at the imprinted sites in the presence of coexisting molecules, which are then transferred to the fluorescence signal. The synthesized MIP@Fe3O4 was characterized using Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Furthermore, computational studies of the band gap (EHOMO-ELUMO) of the monomers, IMB, and their complexes were performed. These results confirmed that the copolymer is the most appropriate and has high stability (Binding energy; 0.004 x 10-19 KJ) and low reactivity. A comprehensive linear response over IMB concentrations from 5 × 10-6 mol/L to 8 × 10-4 mol/L with a low detection limit of 9.3 × 10-7 mol/L was achieved. Furthermore, the proposed technique displayed long-term stability (over 2 months), high intermediate precision (RSD<2.1 %), good reproducibility (RSD <1.9 %), and outstanding selectivity toward IMB over analogous molecules with similar chemical and spatial structure (no interference by 100 to 150-fold of the competitors). Owing to these merits, the proposed fluorescence sensor was utilized to detect IMB in drug tablets and human plasma, and satisfactory results (99.3-100.4 %) were obtained. Thus, the synthesized fluorescence sensor is a promising platform for IMB sensing in various applications.

Dual benefits of NBD-Cl fluorogenic action and sample pretreatment (SALLE) technology in the assessment of anticoagulant medication: Dabigatran in pharmaceutical capsules and plasma samples

Dabigatran (DBG), marketed as Pradaxa, is an anticoagulant medication prescribed for the treatment and mitigation of blood clots and to lower the risk of stroke in individuals with the heart condition known as atrial fibrillation. This medication is specifically indicated for preventing blood clots post hip or knee replacement surgeries and in patients with a prior history of clots. Compared to warfarin, dabigatran serves as a viable alternative that does not necessitate routine blood monitoring tests. The complimentary benefits associated with SALL (salting-out assisted liquid-liquid extraction) and the fluorogenic capabilities of benzofurazan. These methods were combined to provide an affordable and sensitive DBG assaying method. The spectral strength of the yellow luminous product was examined at 533.8 nm and by adjustment of a wavelength of 474.7 nm for excitation. To assess its linearity, the calibration chart was tested across a DBG concentration range of 30-500 ng/ml. Via accurate computation based on ICH, the detection limit (LD) was determined to be 9.5 ng/ml, and the strategy can quantify the DBG to a limit of 28 ng/ml. To ensure success, various crucial parameters for method implementation have been extensively studied and adapted. The validation of the strategy adhered to the policies outlined by ICH, affirming its precision in quantifying DBG in capsules. Furthermore, the inclusion of SALLE steps facilitated accurate monitoring of DBG in plasma samples, introducing a unique and advanced methodology for analyzing this compound in biological samples.

Highly sensitive electrochemical sensing of norfloxacin by molecularly imprinted composite hollow spheres

Poly (3,4-ethylenedioxythiophene) (PEDOT)-based molecularly imprinted electrochemical sensors have attracted widespread attention for monitoring contaminants in food and the environment. However, there are still problems such as poor hydrophilicity, easy agglomeration, and low selectivity in its preparation. In this work, a novel molecularly imprinted composite hollow sphere was prepared by a molecular imprinting technique using nitrogen-doped hollow carbon spheres as matrix material, and PEDOT and poly(methacrylic acid) as monomers. The selective binding capabilities and mechanism of the material to norfloxacin (NOR) were systematically investigated. Then the material-based sensor was constructed, and its electrochemical detection performance toward NOR was thoroughly studied. The sensor exhibited a wide linear range (0.0005-31 μM), a low detection limit (0.061 nM), satisfactory immunity to interference and stability. Besides, the sensor displayed better sensitivity and reliability (spiked recoveries of 98.0-105.2%, relative standard deviation of 3.45-5.69%) for detecting NOR in lake water, honey, and milk than high-performance liquid chromatography. This work provides a new strategy for developing poly(3,4-ethylenedioxythiophene)-based molecularly imprinted electrochemical sensors.

Electrochemical Monitoring in Anticoagulation Therapy

The process of blood coagulation, wherein circulating blood transforms into a clot in response to an internal or external injury, is a critical physiological mechanism. Monitoring this coagulation process is vital to ensure that blood clotting neither occurs too rapidly nor too slowly. Anticoagulants, a category of medications designed to prevent and treat blood clots, require meticulous monitoring to optimise dosage, enhance clinical outcomes, and minimise adverse effects. This review article delves into the various stages of blood coagulation, explores commonly used anticoagulants and their targets within the coagulation enzyme system, and emphasises the electrochemical methods employed in anticoagulant testing. Electrochemical sensors for anticoagulant monitoring are categorised into two types. The first type focuses on assays measuring thrombin activity via electrochemical techniques. The second type involves modified electrode surfaces that either directly measure the redox behaviours of anticoagulants or monitor the responses of standard redox probes in the presence of these drugs. This review comprehensively lists different electrode compositions and their detection and quantification limits. Additionally, it discusses the potential of employing a universal calibration plot to replace individual drug-specific calibrations. The presented insights are anticipated to significantly contribute to the sensor community's efforts in this field.

The Effect of Polymerization Techniques on the Creation of Molecularly Imprinted Polymer Sensors and Their Application on Pharmaceutical Compounds

Molecularly imprinted polymers (MIPs) have become more prevalent in fabricating sensor applications, particularly in medicine, pharmaceuticals, food quality monitoring, and the environment. The ease of their preparation, adaptability of templates, superior affinity and specificity, improved stability, and the possibility for downsizing are only a few benefits of these sensors. Moreover, from a medical perspective, monitoring therapeutic medications and determining pharmaceutical compounds in their pharmaceutical forms and biological systems is very important. Additionally, because medications are hazardous to the environment, effective, quick, and affordable determination in the surrounding environment is of major importance. Concerning a variety of performance criteria, including sensitivity, specificity, low detection limits, and affordability, MIP sensors outperform other published technologies for analyzing pharmaceutical drugs. MIP sensors have, therefore, been widely used as one of the most crucial techniques for analyzing pharmaceuticals. The first part of this review provides a detailed explanation of the many polymerization techniques that were employed to create high-performing MIP sensors. In the subsequent section of the review, the utilization of MIP-based sensors for quantifying the drugs in their pharmaceutical preparation, biological specimens, and environmental samples are covered in depth. Finally, a critical evaluation of the potential future research paths for MIP-based sensors clarifies the use of MIP in pharmaceutical fields.

Investigation of the electrochemical properties of edoxaban using glassy carbon and boron-doped diamond electrodes and development of an eco-friendly and cost effective voltammetric method for its determination

In this study, the highly risky drug Edoxaban (EDX), which can threaten life and cause bleeding, was electro analytically evaluated. The electrochemical behavior of EDX was investigated using glassy carbon electrode (GCE) and boron-doped diamond electrode (BDDE). In this study, for the first time, a simple, rapid, sensitive, and selective voltammetric technique was developed by using different electrodes for the electrochemical characterization and detection of EDX. The optimized voltammetric technique showed anodic signals of EDX at +1.09 V and +1.08 V on GCE and BDDE, respectively, in BR (pH 5.0) solution. The developed voltammetric method provided a very good analytical working range for EDX in BR (pH 5.0) solution on GCE and BDDE, covering concentration ranges from 1.84 μM to 12.88 μM and from 3.68 μM to 14.72 μM, respectively. The limits of detection for EDX on GCE and BDDE under these experimental conditions were calculated as 0.24 μM and 0.57 μM, respectively. The developed voltammetric methods on both electrodes were successfully applied to urine and tablet samples. Additionally, the obtained voltammetric results were compared with UV-Vis spectroscopy results.

Disposable solar microcell array-based addressable photoelectrochemical sensor for high-throughput and multiplexed analysis of salivary metabolites

The high-throughput detection of multiple metabolites in saliva by electrochemical sensors is usually a challenge, which however is essential to the comprehensive evaluation of health status or screening of diseases. Here, a light-addressable and paper-based hydrogen peroxide (H₂O₂) photoelectrochemical (PEC) sensor for the high-throughput detection of multiple salivary metabolites is reported. This sensor has a unique solar microcell array structure with a silver nanowires/fullerene-Congo red (AgNWs/C₆₀-CR) disc working electrode (WE) and a single-walled carbon nanotubes/platinum nanowires (SWCNTs/PtNWs) ring reference/counter electrode (RE/CE) in each microcell. Enzymes of different metabolites are immobilized on different separated microcells of a cover slide over the sensor, from which enzymatically produced H₂O₂ can react with p-hydroxyphenyl boric acid (4-HPBA) on the WE of the sensor to generate hydroquinone (HQ) for photocurrent responses. Based on this strategy, a disposable PEC sensor of saliva was developed, which allows the multiplexed detection of uric acid (UA), glucose (GLU) and lactate (LA) in diluted human saliva with high sensitivity and selectivity. Moreover, the detection throughput and application field of the sensor can be easily extended by connecting a series of sensors in parallel or varying the enzymes. The present work thus establishes a cost-effective approach to the scalable construction of versatile biosensing platforms with tunable throughput and varied analytes.