Molecularly imprinted polymer based electrochemical sensor for quantitative detection of SARS-CoV-2 spike protein.

The continued spread of the coronavirus disease and prevalence of the global pandemic is exacerbated by the increase in the number of asymptomatic individuals who unknowingly spread the SARS-CoV-2 virus. Although remarkable progress is being achieved at curtailing further rampage of the disease, there is still the demand for simple and rapid diagnostic tools for early detection of the COVID-19 infection and the following isolation. We report the fabrication of an electrochemical sensor based on a molecularly imprinted polymer synthetic receptor for the quantitative detection of SARS-CoV-2 spike protein subunit S1 (ncovS1), by harnessing the covalent interaction between 1,2-diols of the highly glycosylated protein and the boronic acid group of 3-aminophenylboronic acid (APBA). The sensor displays a satisfactory performance with a reaction time of 15 min and is capable of detecting ncovS1 both in phosphate buffered saline and patient's nasopharyngeal samples with LOD values of 15 fM and 64 fM, respectively. Moreover, the sensor is compatible with portable potentiostats thus allowing on-site measurements thereby holding a great potential as a point-of-care testing platform for rapid and early diagnosis of COVID-19 patients.

Molecular mechanism of mitoquinol mesylate in mitigating the progression of hepatocellular carcinoma-in silico and in vivo studies.

The safety and efficacy of mitoquinol mesylate (MitoQ) in attenuating the progression of hepatocellular carcinoma (HCC) in Wistar rats has been reported. However, the binding modes for MitoQ as well as its molecular mechanisms in cirrhosis and liver cancer have not been fully investigated. This study sought to understand the structural and molecular mechanisms of MitoQ in modulating the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and mitochondrial succinate dehydrogenase (SDH) in cirrhotic-HCC rats. The research indicates that the upregulated Nrf2 expression in cirrhotic-HCC rats was significantly (p < 0.05) reduced by MitoQ while the activity of SDH was significantly (p < 0.05) increased. Analysis of binding modes revealed MitoQ interacts with amino acid residues in the active pocket of tramtrack and bric-a-brac (BTB) and KELCH domains of KEAP1 with average binding affinities of -66.46 and -74.74 kcal/mol, respectively. Also, MitoQ interacted with the key amino acid residues at the active site of mitochondrial complex II with a higher average binding affinity of -75.76 kcal/mol compared to co-crystallized ligand of complex II (-62.31 kcal/mol). Molecular dynamics simulations data showed the binding of MitoQ to be stable with low eigenvalues while the quantum mechanics calculations suggest MitoQ to be very reactive with its mechanism of chemical reactivity to be via electrophilic reactions. Thus, MitoQ modulates expression of Nrf2 and enhances activity of mitochondrial SDH in cirrhotic-HCC rats via its interaction with key amino acid residues in the active pocket of BTB and KELCH domains of KEAP1 as well as amino residues at the active site of SDH. These findings are significant in demonstrating the potential of Nrf2 and SDH as possible biomarkers for the diagnosis and/or prognosis of hepatocellular carcinoma in patients. This study also supports repurposing of mitoQ for the treatment/management of liver cirrhosis and HCC.

Molecularly Imprinted Polymer Integrated with a Surface Acoustic Wave Technique for Detection of Sulfamethizole.

The synergistic effect of combining molecular imprinting and surface acoustic wave (SAW) technologies for the selective and label-free detection of sulfamethizole as a model antibiotic in aqueous environment was demonstrated. A molecularly imprinted polymer (MIP) for sulfamethizole (SMZ) selective recognition was prepared in the form of a homogeneous thin film on the sensing surfaces of SAW chip by oxidative electropolymerization of m-phenylenediamine (mPD) in the presence of SMZ, acting as a template. Special attention was paid to the rational selection of the functional monomer using computational and spectroscopic approaches. SMZ template incorporation and its subsequent release from the polymer was supported by IR microscopic measurements. Precise control of the thicknesses of the SMZ-MIP and respective nonimprinted reference films (NIP) was achieved by correlating the electrical charge dosage during electrodeposition with spectroscopic ellipsometry measurements in order to ensure accurate interpretation of label-free responses originating from the MIP modified sensor. The fabricated SMZ-MIP films were characterized in terms of their binding affinity and selectivity toward the target by analyzing the binding kinetics recorded using the SAW system. The SMZ-MIPs had SMZ binding capacity approximately more than eight times higher than the respective NIP and were able to discriminate among structurally similar molecules, i.e., sulfanilamide and sulfadimethoxine. The presented approach for the facile integration of a sulfonamide antibiotic-sensing layer with SAW technology allowed observing the real-time binding events of the target molecule at nanomolar concentration levels and could be potentially suitable for cost-effective fabrication of a multianalyte chemosensor for analysis of hazardous pollutants in an aqueous environment.

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.

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

Hepatitis C is the most common liver disease caused by Hepatitis C virus (HCV), and can evolve into serious health problems e.g. cirrhosis and hepatocellular carcinoma. Nowadays, the initial stage of the disease cannot be practically diagnosed, representing thus an extremely important problem of modern public health care. This study is aimed at the development of a sensor for direct detection of HCV. The sensor utilizes a synthetic recognition element prepared by the technology of molecular imprinting and representing a molecularly imprinted polymer (MIP) having molecular recognition sites of HCV envelope protein E2 (E2-MIP). E2-MIP integrated into an electrochemical sensor platform allows quantitative evaluation of binding of free E2 protein as well as HCV-mimetic particles (HCV-MPs) in human plasma with LOD value of 4.6 × 10-4 ng/mL (for HCV-MPs). The developed electrochemical HCV sensor represents a simple, fast and inexpensive alternative for the existing methods of HCV detection and paves the way for the point-of care diagnostics of Hepatitis C.

Advances in Detection of Antibiotic Pollutants in Aqueous Media Using Molecular Imprinting Technique-A Review.

Antibiotics constitute one of the emerging categories of persistent organic pollutants, characterised by their expansion of resistant pathogens. Antibiotic pollutants create a major public health challenge, with already identifiable detrimental effects on human and animal health. A fundamental aspect of controlling and preventing the spread of pollutants is the continuous screening and monitoring of environmental samples. Molecular imprinting is a state-of-the-art technique for designing robust biomimetic receptors called molecularly imprinted polymers (MIPs), which mimic natural biomolecules in target-selective recognition. When integrated with an appropriate sensor transducer, MIP demonstrates a potential for the needed environmental monitoring, thus justifying the observed rise in interest in this field of research. This review examines scientific interventions within the last decade on the determination of antibiotic water pollutants using MIP receptors interfaced with label-free sensing platforms, with an expanded focus on optical, piezoelectric, and electrochemical systems. Following these, the review evaluates the analytical performance of outstanding MIP-based sensors for environmentally significant antibiotics, while highlighting the importance of computational chemistry in functional monomer selection and the strategies for signal amplification and performance improvement. Lastly, the review points out the future trends in antibiotic MIP research, as it transits from a proof of concept to the much demanded commercially available entity.

Molecularly imprinted polymer-based sensor for electrochemical detection of erythromycin.

The increasing global reports on the occurrence of macrolide antibiotics resistance, especially erythromycin (Ery) resistant strains, suggests the possible presence of these antibiotics in the environment hence, their inclusion in the EU watchlist of water pollutants. Consequently, there is an urgent need for the development of portable and cost effective analytical sensing devices for their monitoring in water. The combination of molecularly imprinted polymer (MIP) as a sensing element with a portable electrochemical transducer such as screen printed electrode (SPE) may offer a valuable approach for the desired routine environmental monitoring. This work demonstrates the preparation of an electrochemical MIP-based sensor for Ery detection in aqueous media. Ery-selective MIP, Ery-MIP was generated directly on SPE, Ery-MIP/SPE via electrochemical polymerization of m-phenylenediamine (mPD). The optimization of sensor performance was achieved with special attention given to the selection of functional monomer, template removal, polymer thickness and incubation time. Ery-MIP/SPE sensor demonstrated the ability to discriminate target analyte against very close analogues i.e clarithromycin and azithromycin in both PBS and tap water. In addition, Ery-MIP/SPE could detect Ery down to low limits (LOD = 0.1 nM and LOQ = 0.4 nM) and exhibited good recovery in tap water. The presented analytical approach could be potentially suited and/or further developed for adequate monitoring of Ery as well as other macrolides in environmental water.

Hybrid molecularly imprinted polymer for amoxicillin detection.

The potential adverse effects of the environmental presence of antibiotics on the ecosystem demands the development of new methods suitable for accurate detection of these micropollutants in various aquatic media. An analytical method exploiting the synergistic effect of a label-free sensing platform combined with a molecularly imprinted polymer (MIP) as robust recognition element could represent an efficient tool for the real-time monitoring of antibiotics. In this work, a hybrid organic-inorganic MIP film (AMO-MIP) selective towards amoxicillin (AMO) was synthesized and integrated with a surface plasmon resonance (SPR) sensor. The film was prepared by sol-gel using methacrylamide (MAAM) as organic functional monomer, tetraethoxysilane (TEOS) as inorganic precursor, and vinyltrimethoxysilane (VTMOS) as coupling agent. The AMO-MIP film characterized with the SPR system demonstrated about 16 times higher binding capacity to AMO than corresponding reference non-imprinted polymer (NIP). AMO-MIP-modified SPR sensors could detect AMO with LoD down to 73 pM and discriminate AMO among structurally similar molecules both in buffer and in tap water. Good reproducibility was achieved for several rebinding-regeneration cycles. The sensor could be stored at room temperature for up to 6 months without losing stability.