MIP-based electrochemical sensor for direct detection of hepatitis C virus via E2 envelope protein

Electrochemical Sensors and Biosensors for Identification of Viruses: A Critical Review

Due to their life cycle, viruses can disrupt the metabolism of their hosts, causing diseases. If we want to disrupt their life cycle, it is necessary to identify their presence. For this purpose, it is possible to use several molecular-biological and bioanalytical methods. The reference selection was performed based on electronic databases (2020-2023). This review focused on electrochemical methods with high sensitivity and selectivity (53% voltammetry/amperometry, 33% impedance, and 12% other methods) which showed their great potential for detecting various viruses. Moreover, the aforementioned electrochemical methods have considerable potential to be applicable for care-point use as they are portable due to their miniaturizability and fast speed analysis (minutes to hours), and are relatively easy to interpret. A total of 2011 articles were found, of which 86 original papers were subsequently evaluated (the majority of which are focused on human pathogens, whereas articles dealing with plant pathogens are in the minority). Thirty-two species of viruses were included in the evaluation. It was found that most of the examined research studies (77%) used nanotechnological modifications. Other ones performed immunological (52%) or genetic analyses (43%) for virus detection. 5% of the reports used peptides to increase the method's sensitivity. When evaluable, 65% of the research studies had LOD values in the order of ng or nM. The vast majority (79%) of the studies represent proof of concept and possibilities with low application potential and a high need of further research experimental work.

Molecularly imprinted composite-based biosensor for the determination of SARS-CoV-2 nucleocapsid protein

This article aims to present a comparative study of three polypyrrole-based molecularly imprinted polymer (MIP) systems for the detection of the recombinant severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid protein (rN). The rN is known for its relatively low propensity to mutate compared to other SARS-CoV-2 antigens. The aforementioned systems include screen-printed carbon electrodes (SPCE) modified with gold nanostructures (MIP1), platinum nanostructures (MIP2), and the unmodified SPCE (MIP3), which was used for control. Pulsed amperometric detection (PAD) was employed as the detection technique, offering the advantage of label-free detection without the need for an additional redox probe. Calibration curves were constructed using the obtained data to evaluate the response of each system. Non-imprinted systems were also tested in parallel to evaluate the contribution of non-specific binding and assess the affinity sensor's efficiency. The analysis of calibration curves revealed that the AuNS-based MIP1 system exhibited the lowest contribution of non-specific binding and displayed a better fit with the chosen fitting model compared to the other systems. Further analysis of this system included determining the limit of detection (LOD) (51.2 ± 2.8 pg/mL), the limit of quantification (LOQ) (153.9 ± 8.3 pg/mL), and a specificity test using a recombinant receptor-binding domain of SARS-CoV-2 spike protein as a control. Based on the results, the AuNS-based MIP1 system demonstrated high specificity and sensitivity for the label-free detection of SARS-CoV-2 nucleocapsid protein. The utilization of PAD without the need for additional redox probes makes this sensing system convenient and valuable for rapid and accurate virus detection.

Clinical diagnosis of viral hepatitis: Current status and future strategies

Viral hepatitis (VH) is a significant public health issue with tremendous potential to aggravate into chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. Recent decade has witnessed remarkable uprising in the drug development and effective treatment of VH. An upsurge is seen in identification of antiviral therapies with low rates of viral resistance, the improvement of Hepatitis B Virus (HBV) vaccination and the development of direct-acting antivirals for Hepatitis C Virus (HCV). But unfortunately, the "2030 worldwide eradication" objective of World Health Organization (WHO) is still unmet. It can be largely attributed to the deficit faced by the healthcare system concerning screening and diagnosis. A timely, accurate and comprehensive screening; encompassing maximum population coverage is essential to combat this disease. However, advancements in VH diagnostics remain inadequate and with a marginal use in routine practice. This paper deliberates upon the lacunae in traditional and prevailing diagnostic methodology of viral hepatitis, especially their inadequacy in meeting the unique situations prevailing low- and middle-income countries (LMIC).

COVID-19 Virus Structural Details: Optical and Electrochemical Detection

The increasing viral species have ruined people's health and the world's economy. Therefore, it is urgent to design bio-responsive materials to provide a vast platform for detecting a different family's passive or active virus. One can design a reactive functional unit for that moiety based on the particular bio-active moieties in viruses. Nanomaterials as optical and electrochemical biosensors have enabled better tools and devices to develop rapid virus detection. Various material science platforms are available for real-time monitoring and detecting COVID-19 and other viral loads. In this review, we discuss the recent advances of nanomaterials in developing the tools for optical and electrochemical sensing COVID-19. In addition, nanomaterials used to detect other human viruses have been studied, providing insights for developing COVID-19 sensing materials. The basic strategies for nanomaterials develop as virus sensors, fabrications, and detection performances are studied. Moreover, the new methods to enhance the virus sensing properties are discussed to provide a gateway for virus detection in variant forms. The study will provide systematic information and working of virus sensors. In addition, the deep discussion of structural properties and signal changes will offer a new gate for researchers to develop new virus sensors for clinical applications.

Electrochemically Synthesized MIP Sensors: Applications in Healthcare Diagnostics

Early-stage detection and diagnosis of diseases is essential to the prompt commencement of treatment regimens, curbing the spread of the disease, and improving human health. Thus, the accurate detection of disease biomarkers through the development of robust, sensitive, and selective diagnostic tools has remained cutting-edge scientific research for decades. Due to their merits of being selective, stable, simple, and having a low preparation cost, molecularly imprinted polymers (MIPs) are increasingly becoming artificial substitutes for natural receptors in the design of state-of-the-art sensing devices. While there are different MIP preparation approaches, electrochemical synthesis presents a unique and outstanding method for chemical sensing applications, allowing the direct formation of the polymer on the transducer as well as simplicity in tuning the film properties, thus accelerating the trend in the design of commercial MIP-based sensors. This review evaluates recent achievements in the applications of electrosynthesized MIP sensors for clinical analysis of disease biomarkers, identifying major trends and highlighting interesting perspectives on the realization of commercial MIP-endowed testing devices for rapid determination of prevailing diseases.

Molecularly Imprinted Heterostructure-Based Electrochemosensor for Ultratrace and Precise Detection of 2-Methylisoborneol in Water

Ultratrace 2-methylisoborneol (2-MIB, ∼ng/L) in source water is the main odorant in the algae-derived odor episodes, whose accurate on-site detection will have a promising application potential. Due to the chemical inertness of 2-MIB, sensitive and selective detection of 2-MIB remains much challenging. Herein, molecularly imprinted polymer cavities were polymerized on the heterostructure Ti3C2Tx@CuFc-metal-organic framework to selectively capture 2-MIB, where the heterostructure could catalyze the probe redox reaction of [Fe(CN)63-/4-] and amplify the corresponding current signals. The prepared electrochemical sensor showed higher sensitivity on 2-MIB detection than the reported ones. Excellent stability, reusability, and selectivity for 2-MIB detection were also verified. The linear range and limit of detection of our sensor for 2-MIB were optimized to 0.0001-100 μg/L and 30 pg/L, respectively, performing much better than the reported sensors. Comparable performance to gas chromatography-mass spectrometry was achieved when the sensor was applied to real water samples with or without 2-MIB standards. Overall, our research has made great progress in the application of an on-site sensor in 2-MIB detection and well advances the development of molecularly imprinted polymer-based electrochemical sensors.

In situ synthesis and dynamic simulation of molecularly imprinted polymeric nanoparticles on a micro-reactor system

Current practices in synthesizing molecularly imprinted polymers face challenges-lengthy process, low-productivity, the need for expensive and sophisticated equipment, and they cannot be controlled in situ synthesis. Herein, we present a micro-reactor for in situ and continuously synthesizing trillions of molecularly imprinted polymeric nanoparticles that contain molecular fingerprints of bovine serum albumin in a short period of time (5-30 min). Initially, we performed COMSOL simulation to analyze mixing efficiency with altering flow rates, and experimentally validated the platform for synthesizing nanoparticles with sizes ranging from 52-106 nm. Molecular interactions between monomers and protein were also examined by molecular docking and dynamics simulations. Afterwards, we benchmarked the micro-reactor parameters through dispersity and concentration of molecularly imprinted polymers using principal component analysis. Sensing assets of molecularly imprinted polymers were examined on a metamaterial sensor, resulting in 81% of precision with high selectivity (4.5 times), and three cycles of consecutive use. Overall, our micro-reactor stood out for its high productivity (48-288 times improvement in assay-time and 2 times improvement in reagent volume), enabling to produce 1.4-1.5 times more MIPs at one-single step, and continuous production compared to conventional strategy.

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.

Molecular imprinting-based sensors: Lab-on-chip integration and biomedical applications

The innovative technology of a marketable lab-on-a-chip platform for point-of-care (POC) in vitro detection has recently attracted remarkable attention. The POC tests can significantly enhance the high standard of medicinal care. In the last decade, clinical diagnostic technology has been broadly advanced and successfully performed in several areas. It seems that lab-on-a-chip approaches play a significant role in these technologies. However, high-cost and time-consuming methods are increasing the challenge and the development of a cost-effective, rapid and efficient method for the detection of biomolecules is urgently needed. Recently, polymer-coated sensing platforms have been a promising area that can be employed in medical diagnosis, pharmaceutical bioassays, and environmental monitoring. The designed on-chip sensors are based on molecular imprinting polymers (MIPs) that use label-free detection technology. Molecular imprinting shines out as a potentially promising technique for creating artificial recognition material with molecular recognition sites. MIPs provide unique advantages such as excellent recognition specificity, high selectivity, and good reusability. This review article aims to define several methods using molecular imprinting for biomolecules and their incorporation with several lab-on-chip technologies to describe the most promising methods for the development of sensing systems based on molecularly imprinted polymers. The higher selectivity, more user-friendly operation is believed to provide MIP-based lab-on-a-chip devices with great potential academic and commercial value in on-site clinical diagnostics and other point-of-care assays.

Biomimetic Material for Quantification of Methotrexate Using Sensor Based on Molecularly Imprinted Polypyrrole Film and MWCNT/GCE

This study investigates biomimetic sensors for the detection of methotrexate contaminants in environmental samples. Sensors inspired by biological systems are the focus of this biomimetic strategy. Methotrexate is an antimetabolite that is widely used for the treatment of cancer and autoimmune diseases. Due to the widespread use of methotrexate and its rampant disposal into the environment, the residues of this drug are regarded as an emerging contaminant of huge concern, considering that exposure to the contaminant has been found to lead to the inhibition of some essential metabolic processes, posing serious risks to humans and other living beings. In this context, this work aims to quantify methotrexate through the application of a highly efficient biomimetic electrochemical sensor constructed using polypyrrole-based molecularly imprinted polymer (MIP) electrodeposited by cyclic voltammetry on a glassy carbon electrode (GCE) modified with multi-walled carbon nanotubes (MWCNT). The electrodeposited polymeric films were characterized by infrared spectrometry (FTIR), scanning electron microscopy (SEM), and cyclic voltammetry (CV). The analyses conducted using differential pulse voltammetry (DPV) yielded a detection limit of 2.7 × 10^-9 mol L^-1 for methotrexate, a linear range of 0.01-125 μmol L^-1, and a sensitivity of 0.152 μA L mol^-1. The results obtained from the analysis of the selectivity of the proposed sensor through the incorporation of interferents in the standard solution pointed to an electrochemical signal decay of only 15.4%. The findings of this study show that the proposed sensor is highly promising and suitable for use in the quantification of methotrexate in environmental samples.

Molecularly Imprinted Solid Phase Extraction Strategy for Quinic Acid

Quinic acid (QA) and its ester conjugates have been subjected to in-depth scientific investigations for their antioxidant properties. In this study, molecularly imprinted polymers (MIPs) were used for selective extraction of quinic acid (QA) from coffee bean extract. Computational modelling was performed to optimize the process of MIP preparation. Three different functional monomers (allylamine, methacrylic acid (MAA) and 4-vinylpyridine (4-VP)) were tested for imprinting. The ratio of each monomer to template chosen was based on the optimum ratio obtained from computational studies. Equilibrium rebinding studies were conducted and MIP C, which was prepared using 4-VP as functional monomer with template to monomer ratio of 1:5, showed better binding performance than the other prepared MIPs. Accordingly, MIP C was chosen to be applied for selective separation of QA using solid-phase extraction. The selectivity of MIP C towards QA was tested versus its analogues found in coffee (caffeic acid and chlorogenic acid). Molecularly imprinted solid-phase extraction (MISPE) using MIP C as sorbent was then applied for selective extraction of QA from aqueous coffee extract. The applied MISPE was able to retrieve 81.918 ± 3.027% of QA with a significant reduction in the amount of other components in the extract.