Polymer-based Sensor Research Articles

A Label-Free and Antibody-Free Molecularly Imprinted Polymer-Based Impedimetric Sensor for NSCLC-Cells-Derived Exosomes Detection.

In this study, a label-free and antibody-free impedimetric biosensor based on molecularly imprinting technology for exosomes derived from non-small-cell lung cancer (NSCLC) cells was established. Involved preparation parameters were systematically investigated. In this design, with template exosomes anchored on a glassy carbon electrode (GCE) by decorated cholesterol molecules, the subsequent electro-polymerization of APBA and elution procedure afforded a selective adsorption membrane for template A549 exosomes. The adsorption of exosomes caused a rise in the impedance of the sensor, so the concentration of template exosomes can be quantified by monitoring the impedance of GCEs. Each procedure in the establishment of the sensor was monitored with a corresponding method. Methodological verification showed great sensitivity and selectivity of this method with an LOD = 2.03 × 103 and an LOQ = 4.10 × 104 particles/mL. By introducing normal cells and other cancer cells derived exosomes as interference, high selectivity was proved. Accuracy and precision were measured, with an obtained average recovery ratio of 100.76% and a resulting RSD of 1.86%. Additionally, the sensors' performance was retained at 4 °C for a week or after undergoing elution and re-adsorption cycles seven times. In summary, the sensor is competitive for clinical translational application and improving the prognosis and survival for NSCLC patients.

Silver chalcogenide loaded V2CTx MXene-molecularly imprinted polymer-based novel ratiometric sensor for the early predictive cancer marker: L-Fucose

Fucosylated-haptoglobin (Hpt) and urinary free L-fucose (FU) are primary markers in the progression of tumor and metastasis-related to cancer of the liver (Hepatocellular carcinoma), pancreatic, prostate, colon and oral cancer. The p-aminobenzoic acid (PABA)-FU containing molecularly imprinted polymer (MIP) cavities were accessed to detect FU molecules with signal amplifying layer of novel silver selenide (Ag2Se) doped vanadium carbide (V2CTx) MXene. The selection of suitable monomers through theoretical calculations and optimization of factors involved in the fabrication of a MIP-based sensor via Taguchi orthogonal array (5 × 5) was abundant in improvising the sensor performance. Ratiometry of the oxidation response of FU (IFU) and Ag2Se@V2CTx (IM) played a vital role in eliminating the interference of serum proteins which includes Hpt (undigested), thus sample pretreatment is not required. The extraordinary selectivity with remarkable LOD (1.85 μM) was achieved for FU detection in 100 mM PBS (pH = 6.0) and structurally mimicking interferents failed to show an impactful response against the sensor. Urinary-free FU (spiked) and serum FU (unspiked and spiked) were analyzed in which the LOD of urinary-free FU was as low as 2.22 μM. In addition, normal human serum showed 440.2 μM of FU and the %recovery of FU-spiked samples was between 98.0 and 101.5%.

Molecularly Imprinted Polymer-Based Electrochemical Sensors for the Diagnosis of Infectious Diseases.

The appearance of biological molecules, so-called biomarkers in body fluids at abnormal concentrations, is considered a good tool for detecting disease. Biomarkers are usually looked for in the most common body fluids, such as blood, nasopharyngeal fluids, urine, tears, sweat, etc. Even with significant advances in diagnostic technology, many patients with suspected infections receive empiric antimicrobial therapy rather than appropriate treatment, which is driven by rapid identification of the infectious agent, leading to increased antimicrobial resistance. To positively impact healthcare, new tests are needed that are pathogen-specific, easy to use, and produce results quickly. Molecularly imprinted polymer (MIP)-based biosensors can achieve these general goals and have enormous potential for disease detection. This article aimed to overview recent articles dedicated to electrochemical sensors modified with MIP to detect protein-based biomarkers of certain infectious diseases in human beings, particularly the biomarkers of infectious diseases, such as HIV-1, COVID-19, Dengue virus, and others. Some biomarkers, such as C-reactive protein (CRP) found in blood tests, are not specific for a particular disease but are used to identify any inflammation process in the body and are also under consideration in this review. Other biomarkers are specific to a particular disease, e.g., SARS-CoV-2-S spike glycoprotein. This article analyzes the development of electrochemical sensors using molecular imprinting technology and the used materials' influence. The research methods, the application of different electrodes, the influence of the polymers, and the established detection limits are reviewed and compared.

Development of core-shell magnetic molecularly imprinted polymer-based electrochemical sensor for sensitive and selective detection of ezetimibe

A sensitive electrochemical molecularly imprinted polymer (MIP) sensor was fabricated for detection of ezetimibe (Eze) as an effective cholesterol absorption inhibitor on the surface of a screen-printed carbon electrode based on a magnetic nanoparticle decorated with MIP (Fe3O4@MIP). Placing the magnetic nanoparticle inside the MIP increases the biocompatibility, surface-to-volume ratio, and sensitivity of the sensor. Methacrylic acid (MAA) was used as a monomer, ethylene glycol dimethacrylate (EGDMA) as a cross-linker, and Eze as a template. The fabricated Fe3O4@MIP was characterized using Fourier-transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Detection of Eze was achieved by differential pulse voltammetry. Using this sensor, Eze can be sensitively detected in the range of 1.0 nM–10 μM and detection limit of 0.7 nM. In addition, we have shown that the proposed sensor successfully detects different concentrations of Eze in human serum samples and thus proves its practical application.

A Molecularly Imprinted Polymer-Based Electrochemical Sensor for Heart Failure Detection

The number of Heart Failure (HF) patients is increasing every year, which suggests that early BNP detection is necessary. It is highly desired to look for a new sensor because the Brain Natriuretic Peptide (BNP) has the potential to be a cardiac biomarker for the diagnosis of HF. Due to this, the goal of this study was to create and develop a novel electrochemical sensor for BNP detection based on Molecularly Imprinted Polymer (MIP) rather than an antibody. The modification of carbon Screen Printed Electrode (SPCE) using functionalized-multiwall carbon nanotube/tris (bipyridine) ruthenium (II) chloride (f-MWCNTs/Ru) composites has the advantage of improving the electrode's electron transfer process, as effectively shown by the Cyclic Voltammogram (CV). Pyrrole (Py) and pyrrole-3-carboxylic acid (Py3C) were used as a copolymeric matrix to create the BNP recognition sites. BNP and two monomers were electropolymerized together in a single step by CV method. Differential Pulse Voltammetry (DPV) was used to determine the optimum conditions for the MIP-based BNP sensor, including the Py: Py3C ratio, the number of electropolymerizations, the rebinding pH, and the rebinding time. The DPV results of the new MB labeled NPs revealed directly proportional to the concentrations of rebinding BNP from 10 to 500 pg.cm-3 under optimal conditions, making them acceptable for the detection of both chronic and acute HF. This approach provides an improved detection range and may provide a novel and efficient platform for protein biomarkers.

Fabrication of a selective and sensitive electro-synthesized molecularly imprinted polymer-based electrochemical sensor for the determination of xanthine

Fabrication of a selective and sensitive electro-synthesized molecularly imprinted polymer-based electrochemical sensor for the determination of xanthine

A chemosensitive-based ammonia gas sensor with PANI/PEO–ZnO nanofiber composites sensing layer

Purpose This study aims to investigate the ammonia-sensing performance of polyaniline/polyethylene oxide (PANI/PEO) and polyaniline/polyethylene oxide/zinc oxide (PANI/PEO-ZnO) composite nanofibers at room temperature. Design/methodology/approach Gas sensor structures were fabricated using microfabrication techniques. First, onto the SiO2 wafer, gold electrodes were fabricated via thermal evaporation. PANI/PEO nanofibers were produced by the electrospinning method, and the ZnO layer was deposited by using radio frequency (RF) magnetron sputtering on the electrospun nanofibers as a sensing layer. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray diffraction were performed to characterize the analysis of nanofibers. After all, gas sensing analysis of PANI/PEO and PANI/PEO/ZnO nanofibers was conducted using an experimental setup at room temperature conditions. Furthermore, the impact of humidity (17%–90% RH) on the sensor resistance was actively investigated. Findings FTIR analysis confirms the presence of functional groups of PANI, PEO and ZnO in nanofiber structure. SEM micrographs demonstrate beads-free, thinner and smooth nanofibers with ZnO contribution to electrospun PANI/PEO nanofibers. Moreover, according to the gas sensing results, the PANI/PEO nanofibers exhibit 115 s and 457 s response time and recovery time, respectively. However, the PANI/PEO/ZnO nanofibers exhibit 245 s and 153 s response time and recovery time, respectively. PANI/PEO/MOx composite nanofibers ensure stability to the NH3 gas owing to the high surface/volume ratio and decrease in the humidity dependence of gas sensors, making gas sensors more stable to the environment. Originality/value In this study, ZnO was deposited via RF magnetron sputtering techniques on PANI/PEO nanofibers as a different approach instead of in situ polymerization to investigate and enhance the sensor response and recovery time of the PANI/PEO/ZnO and PANI/PEO composite nanofibers to ammonia. These results indicated that ZnO can enhance the sensing properties of conductive polymer-based resistive sensors.

Polymer-based Electrochemical Sensor: Fast, Accurate, and Simple Insulin Diagnostics Tool

Study of the use of polymers with higher conductivity like polypyrrole, and polyaniline in the electrochemical insulin sensors can overcome the drawbacks arising from the ongoing use of non-conductive polymer membrane. Conductive polymer membranes maintain the positive properties of polymers, like improved stability, reproducibility, and even increase the current response of the prepared sensor toward insulin oxidation. Three different screen-printed electrodes modified with polyaniline, polypyrrole, or chitosan with electrochemically deposited nickel nanoparticles ensuring insulin oxidation were prepared. The electrode morphology was examined via SEM with EDX analysis. Also, the electroactive surface area and stability were determined by voltammetric methods. Based on the results, the SPCEs modified by polypyrrole and nickel nanoparticles were determined as the most appropriate for the insulin determination. The NiNPs-PPy-SPCE exhibited a linear range (500 nM–5 µM), a low-down limit of detection (38 nM), high sensitivity (3.98 µA/µM), and excellent result from insulin determination in real samples (human blood serum). The results confirmed the high potential of developed sensor for future research focused on detection of insulin via electrochemistry methods in clinical samples.Graphical

A molecularly imprinted polymer-based electrochemical sensor for the determination of tofacitinib.

Tofacitinib citrate (TOF) is a Janus kinase-3 inhibitor used for rheumatoid arthritis treatment. In this study, a molecularly imprinted polymer (MIP)-based sensor was produced using acrylamide as the functional monomer via photopolymerization technique for the electrochemical determination of TOF. This study is the first one to explain the electrochemical determination of TOF with a highly selective MIP-based sensor. The surface characterization of the MIP-based sensor was performed with scanning electron microscopy and energy-dispersive X-ray spectroscopy methods, and it was expanded with electrochemical characterization by cyclic voltammetry and electrochemical impedance spectroscopy (EIS) methods. TOF determination was performed using differential pulse voltammetry (DPV) and EIS methods in standard solution and spiked serum sample in the linear range between 1×10-11 M and 1×10-10 M. Very low limit of detection and limit of quantification values were found, confirming the sensitivity of the sensor. Recovery analysis with spiked serum and tablet samples verified the sensor's accuracy and applicability using DPV and EIS methods. The selectivity of the sensor was confirmed with imprinting factor and interference studies, and the sensor performance was controlled using non-imprinted polymer for comparisonat every step.

Detection of organic arsenic based on acid-base stable coordination polymer

Organic arsenic, usually found in animal feed and livestock farm wastewater, is a carcinogenic and life-threatening substance. Hence, for the rapid and sensitive detection of organic arsenic, the development of new fluorescent sensors is quite essential. Here, an acid-base stable coordination polymer (HNU-62) was constructed by the introduction of hydrophobic fluorescence ligand, which can be used as a highly selective sensor for the detection of roxarsone (ROX) in water. The limit of detection (LOD) of HNU-62 for ROX was 4.5 × 10-6 M. Furthermore, HNU-62 also exhibits good anti-interference and recyclability, which can be used in detecting ROX in real samples of pig feed. This work provides an alternative approach for the construction of water-stable coordination polymer-based fluorescence sensors.

Mengkaji Kesan Kekonduksian Pengenapan Politiofena / Polipirol /Polianilina (PT /PPY /PANI) di Atas Kaca Indium Timah Oksida (ITO)

The conducting polymer family is widely used in the field of polymer-based sensors. Among the polymers that are often used are polyaniline (PANI), polypyrrole (PPY) and polythiophene (PT). Sensors operate based on the production of signals by analyte molecules which then produce measurements either qualitatively or quantitatively. In addition, the use of conducting polymers in the field of biosensing has highlighted its importance, especially in the fields of biomedicine, environment, food quality control and more. Even so, there are issues that often arise such as controlling and producing signals of the materials used. Appropriate materials and methods also need to be studied. Therefore, this study was conducted to examine the conductivity effect of the deposition of Polythiophene / Polypyrrole / Polyaniline (PPY/ PT/PANI) on Indium Tin Oxide (ITO) Glass. Polyaniline monolayer (PANI) was deposited on the surface of indium tin oxide (ITO) glass using the Langmuir Blodgett (LB) technique. The monolayer surface of PANI particles has been coated with a layer of polypyrrole (PPY) and polythiophene (PT). PPY and PT were dissolved in methanol and then added with p-toluene sulfonic acid (PTSA) to give the same effect as PANI, especially on their back chain structure. The UV-Vis and FTIR spectra prove the existence of peaks resulting from the solubility and doping process against PPY and PT. It was found that the uneven size of the polymer molecules results from the PPY / PANI image because there is a probability that the existing PPY clumps with each other. When PT was applied to the PPY / PANI layer, a combination of the three polymers formed a cavity on the surface of the PT / PPY / PANI layer. It was explained by the analysis of FTIR PT / PPY / PANI which exhibits the existence of bonds between the combined polymers. The material resistance decreases when the three polymers were combined which explains the higher conductivity value obtained.

Evaluation of polymer-based eccentric FBG bending sensor for humidity, strain, temperature and torsion

We analyse and evaluate the sensitivity and robustness of an eccentric fiber Bragg grating sensor micro-structured into a polymer optical fiber under different relative humidity, temperature, strain and torsion conditions. Relative humidity and temperature conditions are established with a climate test chamber and prepared salt solutions. Though made of polymer, the cross-sensitivity of the sensor to relative humidity is low, enabling usage in rapidly changing environment applications, e.g., for movement detecting gloves or in vehicles, but also in high moisture situations. We find a linear dependence on temperature, so that either bending or temperature can be measured separately from each other. After rotation of one end, the sensor measures torsion by observing the light intensity and the change of the full width at half maximum. Strain measurement shows multiple elastic strain regions before final plastic deformations occur. In the next step, the flexible sensor system will be implemented in a sensor glove to monitor finger movement and detect different hand gestures.

Flexible and Wearable Capacitive Pressure Sensor for Monitoring Heart Parameters

The increase in global average life expectancy over the past century has been largely attributed to medical science developments. In this study, we demonstrate a polymer-based capacitive pressure sensor for measuring heart rate and pulse pressure signal. The fabricated sensor has been characterized to evaluate its performance and to verify its repeatability and precision. It is observed that the sensor works in the range of 0 – 8 kPa pressure range and is suitable for measuring the pulse pressure. This sensor has a high sensitivity of 7.11 kPa <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> in the low-pressure range of 0 to 8 kPa. Further, the sensor demonstrated a considerable amount of repeatability with an error less than 6% in consecutive measurements. Moreover, the sensor demonstrated the use of a wearable, flexible piezo-capacitive pressure sensor for pulse pressure monitoring. The wrist pulse was used as the stimulus for the experimental characterization of the sensor, and health markers related to the measured response were also discussed.

Plasma-Polymerized and Iodine-Doped Polyvinyl Acetate for Volatile Organic Compound Gas Sensing Applications

Nowadays, the increased emission of hazardous volatile organic compounds (VOCs) due to rapid growth in the manufacturing industry has enforced demand for highly sensitive, selective, and stable gas sensors. Among the different types of gas sensors, we resolved issues associated with chemoresistive alcohol sensors like low selectivity, temperature instability, and long-term instability using iodine-doped polyvinyl acetate (IPVAc) films. These polymer-based chemoresistive sensors will be beneficial for low power consumption, ease of manufacture, and long-term stability owing to their simple structure and operation. The polymer films were prepared using the inductively coupled tubular plasma polymerization method. These films were doped with iodine at room temperature. The physicochemical characterization of prepared films confirmed the uniform coating of granular type morphology, iodine doping, and cubical crystal structure. The obtained maximum sensitivity was 122 and 7360 a.u. for 1000 ppm of methanol gas for polyvinyl acetate (PVAc) and IPVAc films, respectively. Also, IPVAc films demonstrated sensitivities of 5554 and 1995 a.u. for 1000 ppm of each ethanol and 2-propanol gas, respectively. IPVAc films illustrated the highest selectivity of 600 a.u. for alcohols over other VOCs like acetone, benzene, toluene, and dichloromethane. The high electronegativity of IPVAc films due to iodine doping is the key origin of the highly selective adsorption of VOCs. Additionally, the IPVAc films have stable sensitivity performance over the temperature range of 30–130 °C and repeatability over 60 days. Thus, the plasma-polymerized IPVAc films can be applied for fabricating highly selective, sensitive, and stable VOC sensing applications.

Design and Development of Polymer-Based Optical Fiber Sensor for GAIT Analysis

In the present scenario like COVID-19 pandemic, to maintain physical distance, the gait-based biometric is a must. Human gait identification is a very difficult process, but it is a suitable distance biometric that also gives good results at low resolution conditions even with face features that are not clear. This study describes the construction of a smart carpet that measures ground response force (GRF) and spatio-temporal gait parameters (STGP) using a polymer optical fiber sensor (POFS). The suggested carpet contains two light detection units for acquiring signals. Each unit obtains response from 10 nearby sensors. There are 20 intensity deviation sensors on a fiber. Light-emitting diodes (LED) are triggered successively, using the multiplexing approach that is being employed. Multiplexing is dependent on coupling among the LED and POFS sections. Results of walking experiments performed on the smart carpet suggested that certain parameters, including step length, stride length, cadence, and stance time, might be used to estimate the GRF and STGP. The results enable the detection of gait, including the swing phase, stance, stance length, and double supporting periods. The suggested carpet is dependable, reasonably priced equipment for gait acquisition in a variety of applications. Using the sensor data, gait recognition is performed using genetic algorithm (GA) and particle swarm optimization (PSO) technique. GA- and PSO-based gait template analyses are performed to extract the features with respect to the gait signals obtained from polymer optical gait sensors (POGS). The techniques used for classification of the obtained signals are random forest (RF) and support vector machine (SVM). The accuracy, sensitivity, and specificity results are obtained using SVM classifier and RF classifier. The results obtained using both classifiers are compared.

Inkjet-printed plasma-functionalized polymer-based capacitive sensor for PAHs

The inkjet-printing technology is utilized to foster conducting layers, interconnections, and other features on different substrates of which its success greatly depends on the surface properties of the substrates. In the present work, we reported the use of low-temperature plasma (LTP) to assist in tailoring the surface properties of polyethylene terephthalate (PET). This facilitated the inkjet printing of a capacitive electrode sensor design using silver nano-ink (AgNI) for polycyclic aromatic hydrocarbons (PAHs). PAHs are ubiquitous environmental pollutants that are of great health concern. We have sifted methyl methacrylate (MMA), N-vinylpyrrolidone (VP), and oxygen (O2) as plasma fed-gases for improving the adhesion of printed AgNI on PET. We observed improved surface hydrophilicity of the plasma-treated PET (p-PET). This was evidenced by the decrease in water contact angle (WCA). The change in surface chemistry with plasma treatment was assessed using X-ray Photoelectron spectroscopy (XPS). Atomic Force Microscopy (AFM) was employed in determining the nanoscale surface roughness of PET. We then fabricated the capacitive sensor using AgNI to quantitatively sense the PAH from aqueous media. This sensor was subsequently characterized using Scanning Electron Microscopy (SEM) and Keyence 3D imaging. The capacitance values have shown a linear response with increased PAH concentration. The sensor design exhibits a high sensitivity for PAH concentrations up to 0.05 ng/mL. Ultimately, these results have demonstrated the potential of this polymer device for pollutant sensing applications.

Embedded Six-DoF Force–Torque Sensor for Soft Robots With Learning-Based Calibration

Soft robots typically exhibit large deformation that makes integrating rigid sensors cumbersome. Especially for soft surgical robots, direct sensor-based feedback is required. In this study, we have proposed, modeled, prototyped, and validated a novel smart polymer-based soft sensor for integration with soft robots. Previously, we have shown that the proposed smart polymer exhibits piezoresistivity. Thus, in this study, we integrated the proposed sensor with a flexural soft robot. Afterward, the sensor was calibrated through a series of experimental tests, and a multilayer perceptron (MLP) was trained for the calibration. The calibration showed a maximum root-mean-square error (RMSE) of 10.6 mN and a mean absolute error of 8 ± 10 mN compared with the ground truth. The experimental validation showed that the proposed sensor and calibration method demonstrated a combined mean absolute error of 7.4 ± 6.5 mN. In addition, the minimum detectable force of the sensor was less than 1 mN with a range of up to 284 mN. The system performance was compatible with representative intraluminal applications’ range and accuracy requirements.

Formaldehyde Gas Sensors Fabricated with Polymer-Based Materials: A Review

Formaldehyde has been regarded as a common indoor pollutant and does great harm to human health, which has caused the relevant departments to pay attention to its accurate detection. At present, spectrophotometry, gas chromatography, liquid chromatography, and other methods have been proposed for formaldehyde detection. Among them, the gas sensor is especially suitable for common gaseous formaldehyde detection with the fastest response speed and the highest sensitivity. Compared with the formaldehyde sensors based on small molecules, the polymer-based sensor has higher selectivity but lower sensitivity because the polymer-based sensor can realize the specific detection of formaldehyde through a specific chemical reaction. Polymer-related formaldehyde sensors can be very versatile. They can be fabricated with a single polymer, molecularly imprinted polymers (MIP), polymer/metal-oxide composites, different polymers, polymer/biomass material composites, polymer/carbon material composites, and polymer composites with other materials. Almost all of these sensors can detect formaldehyde at ppb levels under laboratory conditions. Moreover, almost all polymer nanocomposite sensors have better sensitivity than single polymer sensors. However, the sensing performance of the sensor will be greatly reduced in a humid environment due to the sensitive coating on the gaseous formaldehyde sensor, which is mostly a hydrophilic polymer. At present, researchers are trying to improve the sensitive material or use humidity compensation methods to optimize the gaseous formaldehyde sensor. The improvement of the practical performance of formaldehyde sensors has great significance for improving indoor living environments.

Application of a PLA/PBAT/Graphite sensor obtained by electrospinning on determination of 2,4,6-trichlorophenol

ABSTRACT The widespread use of pesticides requires effective detection and quantification tools to improve monitoring of environmental quality. Electrochemical sensors offer a fast and sensitive response, and can also be optimized by combining several constituents and techniques, including biodegradable materials, being useful in the determination of chemical agents from environmental samples. Here, we produced a polymer-based sensor for 2,4,6-trichlorophenol determination, through electrospinning of poly(lactic acid)/poly(butylene adipate-co-terephthalate) (PLA/PBAT) blend with graphite. The graphite-containing fibres were thermally treated and wetted in mineral oil, thus forming a paste, used as an electrode in the electrochemical sensor. The thermal analysis indicated a disorganization of the polymeric chains between the aromatic carbon chain of the PBAT polymer, resulting in a material with low enthalpy, lower crystallinity and greater thermal degradability after insertion of graphite in polymeric fibres. NIR spectra revealed changes related to the carbonyls of the polymeric ester groups. Cyclic voltammetry and square wave voltammetry techniques were applied to study the electrochemical behaviour of developed sensor. The thermal treatment of graphite-containing fibres increased the adhesion surface in which occurs the adsorption of the analyte on the electrode, which improved the peak current in the electrochemical tests. The PLA/PBAT/Graphite sensor applied to determination of 2,4,6-TCP presented the detection and quantification limits of 7.84 × 10−8 mol L−1 (0.0155 mg L−1) and 2.36 × 10−7 mol L−1 (0.0466 mg L−1) with a linearity response of 1.00 × 10−7 mol L−1 and 2.00 × 10−6 mol L−1 with correlation coefficient of 0.993 (r 2).

An Innovative Polymer-Based Electrochemical Sensor Encrusted with Tb Nanoparticles for the Detection of Favipiravir: A Potential Antiviral Drug for the Treatment of COVID-19.

An innovative polymer-based electro-sensor decorated with Tb nanoparticles has been developed for the first time. The fabricated sensor was utilized for trace determination of favipiravir (FAV), a recently US FDA-approved antiviral drug for the treatment of COVID-19. Different techniques, including ultraviolet-visible spectrophotometry (UV-VIS), cyclic voltammetry (CV), scanning electron microscope (SEM), X-ray Diffraction (XRD) and electrochemical impedance spectroscopy (EIS), were applied for the characterization of the developed electrode TbNPs@ poly m-THB/PGE. Various experimental variables, including pH, potential range, polymer concentration, number of cycles, scan rate and deposition time, were optimized. Moreover, different voltammetric parameters were examined and optimized. The presented SWV method showed linearity over the range of 10-150 × 10-9 M with a good correlation coefficient (R = 0.9994), and the detection limit (LOD) reached 3.1 × 10-9 M. The proposed method was applied for the quantification of FAV in tablet dosage forms and in human plasma without any interference from complex matrices, obtaining good % recovery results (98.58-101.93%).