Core-shell nanocomposite of flower-like molybdenum disulfide nanospheres and molecularly imprinted polymers for electrochemical detection of anti COVID-19 drug favipiravir in biological samples

Needle-in-needle electrochemical sensor for in-vivo monitoring of anticancer drug etoposide

Therapeutic drug monitoring (TDM) serves as a potent tool for adjusting drug concentration within a reasonable range. However, continuous monitoring of anticancer drugs in-vivo presents a significant challenge. Herein, we propose a needle-in-needle electrochemical sensor based on an acupuncture needle electrode, capable of monitoring the anticancer drug etoposide in the peritoneal cavity of living rats. The acupuncture needle was modified with Au nanoparticles and etoposide-templated molecularly imprinted polymer (MIP), resulting in high sensitivity and selectivity in the electrochemical detection of etoposide. The modified acupuncture needle (0.16 mm diameter) was anchored inside a syringe needle (1.40 mm diameter), allowing the outer syringe needle to protect the modified materials of the inner acupuncture needle during skin piercing. Due to the unique needle-in-needle design, high stability was obtained during in-vivo etoposide monitoring. Connecting to a smartphone-controlled portable electrochemical workstation, the needle-in-needle sensor offers great convenience in point-of-care TDM. Moreover, the electrode materials on the acupuncture needle were carefully characterized and optimized. Under the optimized conditions, low detection limits and wide linear range were achieved. This work provides new insights into acupuncture needle electrochemical sensors and further expands the feasibility for real-time and in-vivo detection.

Recent Trends in Nanomaterial Based Electrochemical Sensors for Drug Detection: Considering Green Assessment

An individual's therapeutic drug exposure level is directly linked to corresponding clinical effects. Rapid, sensitive, inexpensive, portable and reliable devices are needed for diagnosis related to drug exposure, treatment, and prognosis of diseases. Electrochemical sensors are useful for drug monitoring due to their high sensitivity and fast response time. Also, they can be combined with portable signal read-out devices for point-of-care applications. In recent years, nanomaterials such as carbon-based, carbon-metal nanocomposites, noble nanomaterials have been widely used to modify electrode surfaces due to their outstanding features including catalytic abilities, conductivity, chemical stability, biocompatibility for development of electrochemical sensors. This review paper presents the most recent advances about nanomaterials-based electrochemical sensors including the use of green assessment approach for detection of drugs including anticancer, antiviral, anti-inflammatory, and antibiotics covering the period from 2019 to 2023. The sensor characteristics such as analyte interactions, fabrication, sensitivity, and selectivity are also discussed. In addition, the current challenges and potential future directions of the field are highlighted.

Molecularly Imprinted Polymer-Based Sensors Integrated with Transition Metal Dichalcogenides (TMDs) and MXenes: A Review

Molecularly imprinted polymer (MIP)-based electrochemical sensors have been extensively researched due to their higher sensitivity, quick response, and operational ease. To develop more advanced sensing devices with enhanced properties, MIPs have been integrated with two-dimensional (2D) layered materials such as transition metal dichalcogenides (TMDs) and MXenes. These 2D materials have unique electronic properties and an extended surface area, making them promising sensing materials that can improve the performance of MIPs. In this review article, we describe the methods used for the synthesis of TMDs and MXenes integrated MIP-based electrochemical sensors. Furthermore, we have provided a critical review of a wide range of analytes determined through the application of these electrochemical sensors. We also go over the influence of TMDs and MXenes on the binding kinetics and adsorption capacity which has enhanced binding recognition and sensing abilities. The combination of TMDs and MXenes with MIPs shows promising synergy in the development of highly efficient recognition materials. In the future, these sensors could be explored for a wider range of applications in environmental remediation, drug delivery, energy storage, and more. Finally, we address the challenges and future perspectives of using TMDs and MXenes integrated MIPs. We conclude with a focus on future development and the scope of integrating these materials in sensing technology.

A highly sensitive and green electroanalytical method for the determination of favipiravir in pharmaceutical and biological fluids

BACKGROUND

Favipiravir is currently used for the treatment of coronavirus disease-2019 (COVID-19).

OBJECTIVE

A highly sensitive and eco-friendly electroanalytical method was developed to quantify favipiravir.

METHOD

The voltammetric method optimized a sensor composed of reduced graphene oxide / modified carbon paste electrode in the presence of an anionic surfactant, improving the favipiravir detection limit. The investigation reveals that favipiravir-oxidation is a diffusion-controlled irreversible process. The effects of various pH and scan rates on oxidation anodic peak current were investigated.

RESULTS

The developed method offers a wide linear dynamic range of 1.5-420 ng/mL alongside a higher sensitivity with a limit of detection in the nanogram range (0.44 ng/mL) and a limit of quantification in the low nanogram range (1.34 ng/mL).

CONCLUSION

The proposed method was applied for the determination of favipiravir in the dosage form, human plasma and urine samples. The developed method exhibited good selectivity in the presence of two potential electroactive biological interferants, uric acid which increases during favipiravir therapy and the recommended co-administered vitamin C. The organic solvent-free method greenness was evaluated via the Green Analytical Procedure Index, The present work offers a simple, sensitive and environment-friendly method fulfilling green chemistry concepts.

The application of multi-walled carbon nanotubes modified pencil graphite electrode for voltammetric determination of favipiravir used in COVID-19 treatment

This study describes the first application of an improved procedure on a pencil graphite electrode decorated with functionalized multi-walled carbon nanotubes (f-MWCNTs/PGE) for the determination of the COVID-19 antiviral drug, favipiravir (FVP). The electrochemical behavior of FVP at f-MWCNTs/PGE was examined by cyclic voltammetry and differential pulse voltammetry (DPV) methods, and it was noted that the voltammetric response significantly increased with the modification of f -MWCNTs to the surface. The linear range and limit of detection from DPV studies were determined as 1-1500 µM and 0.27 µM, respectively. In addition, the selectivity of the method was tested toward potential interferences, which can be present in pharmaceutical and biological samples, and it was found that f-MWCNTs/PGE showed high selectivity for the determination of FVP in the presence of probable interferences. The results with high accuracies and precisions from the obtained feasibility studies also revealed that the designed procedure can be used for accurate and selective voltammetric determination of FVP in real samples.

Graphical abstract

Synchronous spectrofluorimetric determination of favipiravir and aspirin at the nano-gram scale in spiked human plasma; greenness evaluation

Favipiravir and aspirin are co-administered during COVID-19 treatment to prevent venous thromboembolism. For the first time, a spectrofluorometric method has been developed for the simultaneous analysis of favipiravir and aspirin in plasma matrix at nano-gram detection limits. The native fluorescence spectra of favipiravir and aspirin in ethanol showed overlapping emission spectra at 423 nm and 403 nm, respectively, after excitation at 368 nm and 298 nm, respectively. Direct simultaneous determination with normal fluorescence spectroscopy was difficult. The use of synchronous fluorescence spectroscopy for analyzing the studied drugs in ethanol at Δλ = 80 nm improved spectral resolution and enabled the determination of favipiravir and aspirin in the plasma matrix at 437 nm and 384 nm, respectively. The method described allowed sensitive determination of favipiravir and aspirin over a concentration range of 10-500 ng/mL and 35-1600 ng/mL, respectively. The described method was validated with respect to the ICH M10 guidelines and successfully applied for the simultaneous determination of the mentioned drugs in pure form and in the spiked plasma matrix. Moreover, the compliance of the method with the concepts of environmentally friendly analytical chemistry was evaluated using two metrics, the Green Analytical Procedure Index and the AGREE tool. The results showed that the described method was consistent with the accepted metrics for green analytical chemistry.

Universal Hydrogen-Treated TiO2 Nanorod Array/Ti2COX MXene PEC Aptamer Sensor Modulated by the Transport Characteristic of Photogenerated Holes

A semiconductor photoelectrochemical (PEC) aptamer sensor has been widely researched in recent years because of its broad application prospects. However, a universal PEC sensor has not been achieved, and its sensing mechanism based on a photogenerated carrier transfer process has yet to be elucidated. Herein, a novel hydrogen-treated TiO₂ nanorod array one-dimensional (1D)/Ti₂CO_X MXene two-dimensional (2D) (H-TiO₂/Ti₂CO_X) PEC aptamer sensor is presented, which achieved a record detection range of 10^-9-10³ μg/L and a limit of detection (LOD) of 1 fg/L for microcystic toxins-LR detection. Besides, the PEC sensor can also test serotonin (5-HT), aflatoxin-B1, and prostate-specific antigen (PSA) with high performance by changing the aptamers, exhibiting favorable application universality. Furthermore, a new phenomenon of a switchable enhanced/suppressed photocurrent detection signal was discovered from H-TiO₂/Ti₂CO_X PEC aptamer sensors through the variation of the length of the TiO₂ nanorod. Meanwhile, it reveals that the steric hindrance effect determines the photogenerated hole transfer and depolarization processes, which is proposed for the first time as the predominant mechanism of the switchable enhanced/suppressed photocurrent signal for PEC sensors, giving possibilities to develop PEC sensors with higher efficiency.

A Comprehensive Overview of Sensors Applications for the Diagnosis of SARS-CoV-2 and of Drugs Used in its Treatment

During the COVID-19 process, determination-based analytical chemistry studies have had a major place at every stage. Many analytical techniques have been used in both diagnostic studies and drug analysis. Among these, electrochemical sensors are frequently preferred due to their high sensitivity, selectivity, short analysis time, reliability, ease of sample preparation, and low use of organic solvents. For the determination of drugs used in the SARS-CoV-2, such as favipiravir, molnupiravir, ribavirin, etc., electrochemical (nano)sensors are widely used in both pharmaceutical and biological samples. Diagnosis is the most critical step in the management of the disease, and electrochemical sensor tools are widely preferred for this purpose. Diagnostic electrochemical sensor tools can be biosensor-, nano biosensor-, or MIP-based sensors and utilize a wide variety of analytes such as viral proteins, viral RNA, antibodies, etc. This review overviews the sensor applications in SARS-CoV-2 in terms of diagnosis and determination of drugs by evaluating the most recent studies in the literature. In this way, it is aimed to compile the developments so far by shedding light on the most recent studies and giving ideas to researchers for future studies.

Highly dispersed Cu and Ni nano cluster sensor for ultrasensitive electrochemical detection of antiviral drug lamivudine

The accurate and rapid detection for the nucleoside reverse transcriptase inhibitor lamivudine (LAM, 3TC) in cellular systems is always a challenge in the clinic application. Here, a sensitive Cu and Ni nano cluster sensor for LAM is generated under hydrothermal conditions.The Cu and Ni atoms are highly dispersed and aggregated in the nanosized opening pore windows of the synthesized LTA zeolite, through the diatomic synergistic contribution of Cu and Ni and the enrichment of zeolitic channel pores. Using differential pulse voltammetry (DPV), the detection limit (LOD) of LAM at the potential (- 0.15 V) can reach 0.001 pM and the linear range is 0.002 pM-0.002 μM. Since the nano cluster is separated and restricted by the nanosized windows of the zeolite framework, the sensor provides high stability, good recovery (92.5-109%) and RSD (0.8-3.2%) in the analysis of tap water, RPMI 1640 medium, and rabbit serum. The Cu/Ni/LTA zeolite-modified glassy carbon electrode (Cu/Ni/LTA/GCE) exhibits excellent catalytic performance for LAM with high selectivity over potentially interfering agents. A sensitive Cu and Ni nano cluster sensor for LAM is generated in the hydrothermal condition that the Cu and Ni atoms are highly dispersed and aggregated in the nanosized opening pore windows of the as-synthesized LTA zeolite. Through the diatomic synergistic contribution of Cu and Ni and the enrichment of zeolitic channel pores, the observed limit of detection (LOD) can reach 0.001 pM under differential pulse voltammetry (DPV) method with a wide linear relationship to 0.002 μM.

Voltammetric Determination of Favipiravir Used as an Antiviral Drug for the Treatment of Covid-19 at Pencil Graphite Electrode

This work describes the sensitive voltammetric determination of favipiravir (FAV) based on its reduction for the first time with a low-cost and disposable pencil graphite electrode (PGE). In addition, the determination of FAV was also performed based on its oxidation. Differential pulse (DP) voltammograms recorded in 0.5 M H2SO4 for the reduction of FAV show that peak currents increase linearly in the range of 1.0 to 600.0 μM with a limit of detection of 0.35 μM. The acceptable recovery values (98.9-106.0 %) obtained from a pharmaceutical tablet, real human urine, and artificial blood serum samples spiked with FAV confirm the high accuracy of the proposed method.

Electrochemical Sensing of Favipiravir with an Innovative Water-Dispersible Molecularly Imprinted Polymer Based on the Bimetallic Metal-Organic Framework: Comparison of Morphological Effects

Molecularly imprinted polymers (MIPs) are widely used as modifiers in electrochemical sensors due to their high sensitivity and promise of inexpensive mass manufacturing. Here, we propose and demonstrate a novel MIP-sensor that can measure the electrochemical activity of favipiravir (FAV) as an antiviral drug, thereby enabling quantification of the concentration of FAV in biological and river water samples and in real-time. MOF nanoparticles’ application with various shapes to determine FAV at nanomolar concentrations was described. Two different MOF nanoparticle shapes (dodecahedron and sheets) were systematically compared to evaluate the electrochemical performance of FAV. After carefully examining two different morphologies of MIP-Co-Ni@MOF, the nanosheet form showed a higher performance and efficiency than the nanododecahedron. When MIP-Co/Ni@MOF-based and NIP-Co/Ni@MOF electrodes (nanosheets) were used instead, the minimum target concentrations detected were 7.5 × 10−11 (MIP-Co-Ni@MOF) and 8.17 × 10−9 M (NIP-Co-Ni@MOF), respectively. This is a significant improvement (>102), which is assigned to the large active surface area and high fraction of surface atoms, increasing the amount of greater analyte adsorption during binding. Therefore, water-dispersible MIP-Co-Ni@MOF nanosheets were successfully applied for trace-level determination of FAV in biological and water samples. Our findings seem to provide useful guidance in the molecularly imprinted polymer design of MOF-based materials to help establish quantitative rules in designing MOF-based sensors for point of care (POC) systems.