Molecularly Imprinted Polymer Research Articles

A disposable electrochemical sensor for amyloid-β42 protein based on molecular imprinted polymers with nitrogen doped carbon dots-graphene nanohybrid

This work presented a molecularly imprinted polymer (MIP) electrochemical sensor for determination of amyloid-β42 (Aβ42) as an Alzheimer’s disease (AD) biomarker. A nitrogen-doped carbon-dot-graphene (NCD-G) nanohybrid was synthesized through a simple ultrasonic method. Polypyrrole (PPY) was used as an imprinted polymer with an Aβ42 template for the electropolymerization process. The NCD-G and MIP were modified on a screen-printed carbon electrode (SPCE) without binding agent. The morphology and electrochemical properties of MIP/NCD-G modified SPCE were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–Vis spectroscopy, X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV) and square wave voltammetry (SWV). The developed sensor exhibited good linear response in a range from 5 to 70 pg/mL with a limit of detection (LOD) of 1 pg/mL under optimal conditions. This sensor shows excellent performance due to the enhancement of effective surface area, electrical conductivity, and electrocatalytic activity. This MIP sensor takes advantage of molecularly imprinted technique combined with nanohybrid to achieve high selectivity and sensitivity. Moreover, it possessed good reproducibility and miniaturization that could be applied as a platform for portable devices in healthcare in the future. Novelty statementThis work provides the combination of a zero-dimensional and two-dimensional materials, nitrogen doped carbon dots-graphene nanohybrid (NCD-G) by self-assembly through a simple ultrasonication method and applied as a molecularly imprinted polymer (MIP) sensor for determination of amyloid-β42 protein. We propose a minimum number of preparation steps which NCD-G could enhance the MIP sensor performance, owing to the synergistic effects with high selectivity and sensitivity. The hybrid formation of the carbon dots with graphene using their π-π interactions in carbon nanostructures. NCD-G nanohybrid and MIP modified on screen printed carbon electrode (SPCE) for the determination of amyloid-β42 have not been previously investigated. Moreover, this disposable strip is a single-use tool that might be essential for on-site devices.

Comparative study of two MIP-based electrochemical sensors for selective detection and quantification of the antiretroviral drug lopinavir in human serum

Thermal polymerization (TP) and electropolymerization (EP) are the two methods used in this study to explore the molecular imprinting process. To detect the antiviral medication lopinavir (LPV), an inhibitor of enzyme HIV-1 protease that is co-formulated with ritonavir (RTV) to extend its half-life in the body, with greater precision, these methods were merged with an electrochemical sensor. The sensors were created on glassy carbon electrodes (GCE) based on molecularly imprinted polymers (MIP) using TP with methacrylic acid (MAA) functional monomer and EP with p-aminobenzoic acid (PABA) functional monomer. Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and electrochemical methods were utilized to examine the technical features of the suggested sensors. For both approaches, the necessary optimization investigations were carried out. Different LPV concentrations, ranging from 1.0 pM to 17.5 pM in drug solution and commercial human serum samples, were used to validate the analytical efficiency of the two sensors and compare their electroanalytical behaviour. For TP-LPV@MIP/GCE and EP-LPV@MIP/GCE, the corresponding limit of detection (LOD) was 2.68 × 10−13 M (0.169 pg mL−1) and 1.79 × 10−13 M (0.113 pg mL−1) in standard solutions, and 2.87 × 10−13 M (0.180 pg mL−1) and 2.91 × 10−13 M (0.183 pg mL−1) in serum samples. For the measurement of LPV in tablet form and serum samples, the proposed TP-LPV@MIP/GCE and EP-LPV@MIP/GCE sensors provide good recovery, demonstrating 99.85–101.16 % and 100.36–100.97 % recovery, respectively. The imprinting factor was utilized to demonstrate the selectivity of the suggested sensors by utilizing several anti-viral drugs that are structurally comparable to LPV. Additionally, the constructed sensors were examined for the potential impacts of interferences and the stability during the storage.

Ingestible Sensor Based on Fluorescent Gold Nanoparticles and Molecularly Imprinted Polymers on Thread for Localized Quantification of Escherichia Coli in the Gastrointestinal Tract

AbstractThe small intestinal (SI) microbiota plays an important role in human health and disease. Current methods based on fecal analysis do not provide an accurate representation of the SI microbiome. This article introduces an ingestible sensor for the quantification of Escherichia coli (E. coli) in the SI by developing the fluorescent thread‐based ingestible pill analytical device (TPAD) using fluorescent gold nanoclusters (AuNCs) coupled with molecularly imprinted polymers (MIPs). Quantitative detection lies in the change in fluorescence signal on thread as proportional to target bacteria concentrations using a smartphone. Utilizing a pH‐sensitive enteric coating, this device facilitates localized sampling of the SI microbiome. Hydrophilic beads are employed to autonomously seal the device after sampling, offering a self‐locking mechanism. The sensor demonstrates a linear range for E. coli detection between 2.0 × 103 and 14.0 × 103 CFU mL−1 with an R2 of 0.9975 and a detection limit (LOD) of 400.0 × 102 CFU mL−1. The sensor also shows remarkable precision and acceptable accuracy for monitoring E. coli levels in in vivo animal studies compared to commercially available test kits. The developed TPAD, therefore, offers a novel, low‐cost, and non‐invasive method for rapidly diagnosing gastrointestinal (GI)‐related medical conditions and studying host–microbiome interactions.

Selective and sensitive molecularly imprinted polymer-based electrochemical sensor for detection of deltamethrin

Electrochemical sensors have a broad range of industrial applications due to their sensitivity, speed, and cost-effectiveness. These sensors enable the continuous monitoring and control of critical parameters in various industrial processes. For instance, they are essential in food safety, environmental monitoring, biomedical applications, and pharmaceutical production. In the food industry, electrochemical sensors facilitate the rapid and reliable detection of contaminants and pathogens in food products, thus enhancing product quality and consumer safety. An electrochemical sensor was developed with the molecularly imprinted polymer (MIP) technique to detect deltamethrin with high sensitivity and selectivity. The sensor was fabricated by electrodeposition of Co3O4 on indium tin oxide (ITO), followed by electropolymerization of o-phenylenediamine with deltamethrin as a template molecule. The template molecules were then removed from the modified electrode by a methanol. The MIP-based electrochemical sensor exhibited high sensitivity and selectivity towards deltamethrin. Under the optimized conditions, the LOD values for the MIP/Co3O4/ITO electrode in the first and second linear regressions were 1.53 nM for linear range of 2.82 nM to 56.5 nM and 0.34 μM for linear range of 0.25 μM to 3.98 μM. Moreover, the LOD values for the NIP/Co3O4/ITO electrode in the first and second regressions were 2.43 nM for the linear range of 3.91 nM to 65.0 nM and 726.0 nM for the linear range of 0.023 μM to 4.5 μM. The developed electrochromic pesticide sensor, being an electrochemical-based molecularly imprinted polymer (MIP) sensor incorporating electrochromic materials, enables both target-specific pesticide detection and visual pesticide identification based on color changes dependent on pesticide concentration. Consequently, this system is more advantageous compared to electrochemical-based MIP sensors, as it provides both qualitative and quantitative determinations. The qualitative assessment aims to enhance the ease of use of the sensor, thereby increasing the potential for it to become a commercially viable product by reducing the need for instrumental devices.

Selective solid phase extraction of folic acid from tomato as a biological source with a magnetic molecularly imprinted polymer measured by fluorescence spectroscopy

AbstractA novel magnetic molecular-imprinted polymer (MMIP) was used to selectively extract folic acid directly from real samples. Folic acid was used as template molecule, Fe3O4/SiO2-3-triethoxysilyl-propyl-acrylamide as functional monomer, azobisisobutyronitrile as initiation, ethylene glycol dimethacrylate as crosslinker agent, and acrylamide as the secondary monomer in a mixed ethanol-water solvent. The effect of different parameters on the extraction efficiency was studied, and the optimum conditions were established as follows: the concentrations of crosslinking and template were fixed at 0.05 and 0.06 g, absorption percentage was 96.5, pH was adjusted to 8, and extraction time was 8 h with a temperature of 25 °C. By examining the effect of pH, we tried to investigate the effect of the amide groups that present in MMIP and its intermolecular hydrogen interaction with folic acid. After optimising the effective parameters in polymer synthesis and adsorption rate, a magnetic imprinting dispersive solid-phase extraction method combined with fluorescence spectrophotometry at λem = 367 nm (MMIP-DSPE-FL) was constructed for sensitive determination of folic acid in tomato samples. The limit of quantification (LOQ) and limit of detection (LOD) values were 30.00 ± 0.01 μg L−1 and 10.00 ± 0.03 μg L−1, respectively, after the MMIP-DSPE preconcentration. Three tomato samples were analysed to give recoveries in the range of 80.2–81.6%, with relative standard deviation values below 0.6% (n = 3). The prepared MMIP-DSPE showed high selectivity toward folic acid, which could be used six times without changing adsorption capacity. The adsorption isotherm of the folic acid-imprinted polymer pursued the Langmuir model (RL = 0.029), and the kinetics model followed pseudo-first-order (R2 = 0.9974).

Versatile and reliable extraction of phytosterols employing sonochemical synthesized molecularly imprinted polymer

Phytosterols (PSs) are bioactive compounds in the sterol family, present in numerous complex food and plant matrices in free and conjugated forms. The interest in these compounds arises for phytotherapeutic purposes, particularly for their action on cholesterol metabolism and impact on cardiovascular diseases. There is a need to develop approaches that can selectively extract target analytes and accurately identify and quantify them with high precision. This work proposed the synthesis of molecularly imprinted polymers (MIPs) for PSs with a sonochemical approach, enabling a rapid polymerization step (5 min). This proposed MIP was able to extract 8 PSs (brassicasterol, stigmastanol, campesterol, campestanol, stigmasterol, β-sitosterol, Δ5-avenasterol, α-spinasterol) from a wide range of plant and food matrices belonging to different classes (Brassicaceae, dried fruits and Leguminosae) and was coupled to ultra-high liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS). MIP based on dispersed solid phase extraction (dSPE-MIP) and targeted analysis has proven to be particularly effective in addressing the challenges associated with the complexity of plant-derived matrices, minimising interferences. This was demonstrated by the excellent control of the matrix effect, which was within ±15 %, ensuring the robustness and reliability of the method. The identification and quantification of 8 different PSs was successfully achieved with satisfactory recovery values ranging from 65 % to 100 %. The proposed strategy offers an affordable alternative to classical methods, providing enhanced sensitivity, selectivity and overall performance.

Molecular docking and molecular dynamics study of 3-hydroxybutyrate with polymers for diabetic ketoacidosis-targeted molecularly imprinted polymers

Context: Molecularly imprinted polymers (MIPs) are promising materials with tailored binding sites that can selectively recognize and bind target molecules. The combined approach of molecular docking and molecular dynamics (MD) simulation provides valuable insights into the interactions between 3-hydroxybutyrate (3HB) and the designed MIPs, shedding light on the intricate details of their binding mechanisms. This information is crucial for designing MIPs with high selectivity and affinity for 3HB, which is a key biomarker of diabetic ketoacidosis (DKA). Aims: To examine the interactions and dynamic behavior of 3HB in a complex with ten polymers by employing molecular docking and MD simulations. Methods: Initially, molecular docking was employed to predict the binding orientations and affinities of the 3HB molecule within the active sites of the polymers. Subsequently, molecular dynamics simulation was utilized to explore the dynamic behavior, stability, and interactions within these complexes for 100 ns. Metabolic and toxicological properties of 3HB using SwissADME were also predicted. Results: N-(hydroxymethyl)acrylamide (NHMAm), hydroxyethyl methacrylate (HEMA), itaconic acid (ITA), and N-[tris(hydroxymethyl)methyl]acrylamide (TrisNHMAm) displayed the strongest interactions with 3HB, with binding affinities of -2.64, 2.523, 2.469, and 2.305 kcal/mol, respectively. Various kinds of molecular interactions influence ligand-polymer binding in a variety of ways, as illustrated by the four polymers with the lowest binding affinities. In molecular dynamics, 4-vinylpyridine (4VP), N,N-dimethylacylamide (DMAm), N-(hydroxyethyl)acrylamide (NHEAm), and hydroxyethyl methacrylate (HEMA) suggest a strong stable complex with 3HB with an overall ΔTOTAL of -0.56, -0.35, -0.32, and -0.27 kcal/mol, respectively. The ADME prediction indicated that 3HB has favorable pharmacokinetic properties. Conclusions: HEMA shows the ability to interact well with 3HB both by molecular docking and molecular dynamics.

Efficient synthesis of the undiluted vegetable juice-compatible hydrophilic quantum dot-labeled fluorescent molecularly imprinted polymer microspheres via facile one-pot surface-initiated ARGET ATRP

The development of fluorescent molecularly imprinted polymers (MIPs) applicable for herbicide optosensing in the undiluted vegetable juices is highly important for food safety control, but still remains a challenging task. Herein, we report on a facile and efficient new strategy for the synthesis of hydrophilic quantum dot (QD)-labeled fluorescent MIP microspheres capable of directly and selectively optosensing a widely used herbicide (i.e., 2,4-dichlorophenoxyacetic acid, 2,4-D) in the undiluted vegetable juices. Such fluorescent MIP particles were readily prepared through one-step grafting of a red CdTe QD-labeled 2,4-D-MIP layer with hydrophilic polyethylene glycol brushes onto the preformed uniform “living” polymer microspheres (with surface-bound alkyl halide groups) via one-pot surface-initiated activator regenerated by electron transfer (ARGET) atom transfer radical polymerization (ATRP) (SI-ARGET ATRP). They proved to be a highly useful optosensor with high 2,4-D selectivity and sensitivity (the limit of detection ≤ 0.14 μM) in the undiluted Chinese cabbage and cucumber juices. They also showed excellent photostability and reusability and could be directly utilized for 2,4-D detection with high recoveries (98.2 %-102.4 %) and accuracy (RSD≤3.8 %) in the undiluted Chinese cabbage and cucumber juices at three spiking levels of both 2,4-D and its mixtures with several analogues. The use of SI-ARGET ATRP significantly reduced the applied copper catalyst concentration (about 5 μM), which greatly alleviated the quenching effect of the copper catalyst on the fluorescence of the QD-labeled MIP (usually observed for those prepared via normal ATRPs that typically use several hundreds of μM of copper catalysts), thus making this facile new strategy highly efficient for developing advanced fluorescent MIPs that hold much promise in various bioanalytical and diagnostic applications.

Preparation of a surface molecularly imprinted thermo-sensitive polymer for selective trypsin capture

Molecularly imprinted polymers (MIPs) are innovative porous materials created through polymerization templating methods for highly selective, sensitive detection and separation of the desired chemical species, known as template molecules. Surface imprinting over nano-sized substrates with special functional groups is an effective approach for improving the mass transfer and rebinding capacity. In this study, we successfully performed surface imprinting using methacrylic acid (MAA) and thermoresponsive N-isopropyl acrylamide (NIPAm) as functional monomers on acrylic-functionalized silica nanoparticles and served as a Trypsin artificial receptor. The resulting Trypsin imprinted polymer exhibited a binding capacity of 1022.44 mg/g, surpassing the non-imprinted polymer’s capacity of 292.41 mg/g within 45 min. Moreover, the imprinting factor, the main influence factor in MIP performance, was 3.5, demonstrating the significant selectivity of the polymeric products. In addition, due to the temperature sensitivity of NIPAm the template removing process was simply done by changing pore size. The silica nanoparticles and the synthesized MIP particles had diameters of approximately 95 nm and 105 nm, respectively, with the polymer layer thickness being around 5 nm. The MIP adsorption model followed the Freundlich isotherm and pseudo-second-order kinetics resulting in efficiencies of 93.0 % and 95.4 %, respectively. The developed Trypsin imprinted polymer was reusable for four consecutive uses,demonstrating both resilience and selectivity towards Trypsin.

Endosulfan as Potentiometric Sensor in a Kinetic Model of Molecularly Imprinted Polymer (MIP)

Indonesia is an agrarian country with abundant agricultural and plantation land, where farmers often face severe challenge of pests damaging crop yields. To address this challenge, chemical agents such as pesticides and herbicides are used for plant management and care. However, the inappropriate use of these chemical agents poses significant risks to the environment when the prevalence surpasses environmental and human tolerance limits. Pesticides and herbicides containing endosulfan components require proper management to prevent adverse effects on humans and the environment. Therefore, this research aimed to develop Molecularly Imprinted Polymer (MIP) endosulfan pollutant sensors to assess the kinetics of MIP adsorption to endosulfan analyte. Among the various models used for assessment, the Freundlich Isotherm showed optimal results, with an AT value of 1.79 × 107 L/mg, B (Constant related to heat of sorption) of 6 x 10-8 J/mol, and b (Freundlich Isotherm constant) of 4.13×1010. Furthermore, the obtained distribution coefficient (R2) at 0.9768 was more effective compared to other models.

Bioinspired synergy strategy based on the integration of nanozyme into a molecularly imprinted polymer for improved enzyme catalytic mimicry and selective biosensing

Nanozymes offer many advantages such as good stability and high catalytic activity, but their selectivity is lower than that of enzymes. This is because most of enzymes have a protein component (apoenzyme) for substrate affinity to enhance selectivity and a non-protein element (coenzyme) for catalytic activity to improve sensitivity. The synergy between molecularly imprinted polymers (MIPs) and nanozymes can mimic natural enzymes, with MIP acting as the apoenzyme and nanozyme as the coenzyme. Despite researchers' attempts to associate MIPs with nanozymes, the full potential of this combination remains not well explored. This study addresses this gap by integrating Fe3O4-Lys-Cu nanozymes with peroxidase-like catalytic activities within appropriate MIPs for L-DOPA and dopamine. The catalytic performance of the nanozyme was improved by the presence of Cu in Fe3O4-Lys-Cu and further enhanced by MIP. Indeed, the exploration of the pre-concentration property of MIP has increased twenty-fold the catalytic activity of the nanozyme. Moreover, this synergistic combination facilitated the template removal process during MIP production by reducing the extraction time from several hours to just 1 min thanks to the addition of co-substrates which trigger the reaction with nanozyme and release the template. Overall, the synergistic combination of MIPs and nanozymes offers a promising avenue for the design of artificial enzymes.

Selective and sensitive detection of dimethyl phthalate in water using ferromagnetic nanomaterial-based molecularly imprinted polymers and SERS

To overcome the complicated pretreatment, low selectivity and low sensitivity detection associated with the detection of dimethyl phthalate (DMP), this study synthesized ferromagnetic nanomaterials that coupled with surface enhanced Raman scattering (SERS) and molecular imprinting polymers (MIPs). The pretreatment process can be simplified by ferromagnetic nanomaterials, then Fe3O4@SiO2@Ag@MIPs selectively adsorbing DMP can be achieved, and SERS can be applied for DMP detection with high sensitivity. As a control, the non-imprinted polymers (NIPs) Fe3O4@SiO2@Ag@NIPs were synthesized. Adsorption experiments results showed that the saturation adsorption amounts of Fe3O4@SiO2@Ag@MIPs is 36.74 mg/g with 40 mg/L DMP and Fe3O4@SiO2@Ag@NIPs is 17.45 mg/g. For DMP, Fe3O4@SiO2@Ag@MIPs have a greater affinity. In addition, after seven adsorption-desorption cycles the Fe3O4@SiO2@Ag@MIPs are reusable with approximately a 9.8 % loss in adsorption capacity. With an 8.7 × 10−9 M detection limit, DMP detection was performed by SERS, which revealed that the Raman intensities of the associated characteristic peak were linearly proportional to the DMP concentrations. As a result, the recovery rate of the testing artificial water varied from 87.9 % to 117 %. These outcomes show that the suggested technique for finding DMP in actual water samples is practical.

Molecularly Imprinted Microspheres in Active Compound Separation from Natural Product.

Molecularly Imprinted Microspheres (MIMs) or Microsphere Molecularly Imprinted Polymers represent an innovative design for the selective extraction of active compounds from natural products, showcasing effectiveness and cost-efficiency. MIMs, crosslinked polymers with specific binding sites for template molecules, overcome irregularities observed in traditional Molecularly Imprinted Polymers (MIPs). Their adaptability to the shape and size of target molecules allows for the capture of compounds from complex mixtures. This review article delves into exploring the potential practical applications of MIMs, particularly in the extraction of active compounds from natural products. Additionally, it provides insights into the broader development of MIM technology for the purification of active compounds. The synthesis of MIMs encompasses various methods, including precipitation polymerization, suspension polymerization, Pickering emulsion polymerization, and Controlled/Living Radical Precipitation Polymerization. These methods enable the formation of MIPs with controlled particle sizes suitable for diverse analytical applications. Control over the template-to-monomer ratio, solvent type, reaction temperature, and polymerization time is crucial to ensure the successful synthesis of MIPs effective in isolating active compounds from natural products. MIMs have been utilized to isolate various active compounds from natural products, such as aristolochic acids from Aristolochia manshuriensis and flavonoids from Rhododendron species, among others. Based on the review, suspension polymerization deposition, which is one of the techniques used in creating MIPs, can be classified under the MIM method. This is due to its ability to produce polymers that are more homogeneous and exhibit better selectivity compared to traditional MIP techniques. Additionally, this method can achieve recovery rates ranging from 94.91% to 113.53% and purities between 86.3% and 122%. The suspension polymerization process is relatively straightforward, allowing for the effective control of viscosity and temperature. Moreover, it is cost-effective as it utilizes water as the solvent.

Cupric ion coordination-mediated molecularly imprinted electrochemical sensor for the recognition and ratiometric detection of lidocaine

Molecularly imprinted polymers (MIPs) have been widely used as artificial recognition elements in sensing applications. However, their electrochemical sensing performance is generally hampered by limited affinity and uncontrolled condition change. In this work, a novel MIP electrochemical sensor based on metal coordination interaction was prepared and used for the recognition and ratiometric detection of lidocaine (LC). The sensor was constructed by electrodepositing Cu-coordinated MIP on biomass carbon modified glassy carbon electrode. Herein, Cu2+ ions acted as anchor for the immobilization of LC during the synthesis process, enabling the orderly formation of molecular recognition sites. Reversely, the metal coordination between Cu2+ ions and LC molecules facilitated the recognition of LC. Moreover, the doped cupric ions in the polymer film could provide a reference signal for subsequent ratiometric strategy. Thus the resulting sensor exhibited high selectivity, sensitivity, satisfactory reproducibility, and anti-interference ability. Under the selected conditions, the peak current ratio of LC and cupric ion was linear to LC concentration in the range of 0.008–2.5 μmol L−1 (R2 = 0.9951), and the limit of detection was 1.9 nmol L−1 (S/N = 3). The practical feasibility of the sensor was evaluated by detecting human serum and pharmaceutical samples, and satisfactory outcomes were obtained.

Simultaneous detection of enrofloxacin and florfenicol in animal-derived foods based on fluorescence quenching BELISA and a nanozyme catalytic strategy

Enrofloxacin (ENRO) and florfenicol (FF) are animal-specific drugs, but they present great harm to human health. Therefore, it is essential to rapidly and accurately detect ENRO and FF in animal-derived foods simultaneously. Herein, dual-template molecular imprinted polymers (MIPs) with specific recognition of ENRO and FF were prepared, meanwhile, the molar ratios of templates to monomer and cross-linker were optimized and then applied as a bionic antibody to experiment. Based on the principle that the fluorescence of QDs could be efficiently quenched by the enzymatic fabrication of Prussian blue nanoparticles (PBNPs), a novel and sensitive fluorescence quenching biomimetic enzyme-linked immunosorbent assay (BELISA) was established for simultaneous detection of ENRO and FF by the conversion of the absorption signal into fluorescent signals. Under optimal conditions, the detection limit (IC15) was 4.64 ng L−1 for ENRO and 1.33 ng L−1 for FF. Besides, matrix interference of chicken, eggs, milk and shrimp samples, was investigated in our study, and the result indicates that all of the sample matrices had a profound impact on the fluorescence of QDs, especially for milk samples (with Im of 94.10 %). After performing the matrix-elimination experiments, chicken, eggs, milk and shrimp samples spiked with ENRO and FF were extracted and detected by this proposed method, with recoveries ranging from 82.70 to 113.48 %. The results correlated well with those obtained using HPLC. In conclusion, the developed method could be an alternative and sensitive method for the simultaneous detection of ENRO and FF in animal-derived foods.

Enhancing Selectivity with Molecularly Imprinted Polymers via Non-Thermal Dielectric Barrier Discharge Plasma.

Molecularly imprinted polymers (MIPs) are synthetic polymers that mimic the functions of antibodies. Though MIPs are promising tools in various areas, achieving high selectivity in MIPs can be difficult. To improve selectivity, various approaches have been implemented; however, the role of polymerization methods or synthetic techniques in enhancing the selectivity of MIPs has not been studied and remains a crucial area for further research. MIPs are typically prepared from free radical reactions. Recently, we found that Dielectric Barrier Discharge (DBD) plasma can be used to initiate the polymerization of vinyl monomers. The DBD plasma method allows the monomers to associate with the template molecules and initiate polymerization with minimal disruption to the positioning of the monomers. We hypothesize that this could be a preferred method to prepare MIPs over the traditional radical reaction that may cause a disturbance of the pre-associated monomers on the templates for the polymerization. Chicken egg white serum albumin (CESA) was used as the template protein for the MIPs. Our results show that in all test conditions, approximately twofold improvement in selectivity was achieved, which is the primary performance metric for MIPs. This enhancement was evident across all categories, including MIPs prepared from various monomer combinations.

Molecular imprinting electrochemical sensor based on hollow spherical PProDOT-2CH2OH and chitosan-derived carbon materials for highly sensitive detection of chloramphenicol

The misuse of chloramphenicol (CAP) has jeopardized environmental safety. It is critical to create an effective and sensitive CAP detection technique. In this paper, a composite of chitosan (CS)-derived carbon material modified hollow spherical hydroxylated poly(3,4-propylenedioxythiophene) (PProDOT-2CH2OH) was designed, which innovatively used o-phenylenediamine and p-aminobenzoic acid as bi-functional monomers to prepare molecular imprinting polymer (MIP) sensors for highly sensitive analysis and determination of CAP. It was found that the hollow spherical structure of PProDOT-2CH2OH significantly enhanced the rapid electron migration. When combined with the CS-derived carbon material, which has multi-functional sites, it improved the electrical activity and stability of the sensor. It also provided more active centers for the MIP layer to specifically recognize CAP. Therefore, this MIP sensor had a wide linear response (0.0001 ∼ 125 μM), a low limit of detection (LOD, 6.6 pM), excellent selectivity and stability. In addition, studies showed that the sensor has potential practical value. Environmental implicationChloramphenicol (CAP) is one of the most widely used antibiotics with the highest dosage due to its low price and broad-spectrum antimicrobial properties. Due to its incomplete metabolism in living organisms and its difficulty in degrading in the environment, contamination caused by it can pose a threat to public health. In this study, a novel molecularly imprinted sensor (MIP/PC2C1/GCE) was designed to provide a new idea for rapid and precise removal of CAP by adsorption. The detection of CAP in pharmaceutical, water quality, and food fields was realized.

Label-Free Mode Based on Ferrocene/PEDOT:PSS-PPy for Molecularly Imprinted Electrochemically Ultrasensitive Detection of Amino Acids.

Generally, molecularly imprinted (MIP) electrochemical sensors for amino acids operate in a "label-like" mode. That is, after an amino acid is specifically recognized by an imprinted cavity at the sensing interface, the amino acid itself provides the sensing signal for quantitative detection. However, poorly electroactive amino acids impede electron transfer at the sensing interface and require high potentials to drive the reaction; thus, more interfering reactions tend to be triggered in practical applications, causing enhanced background noise in the detection. To address these issues, a "label-free" mode of the MIP sensor based on the ferrocene (Fc)/PEDOT:PSS-polypyrrole (PPy) composite was designed for the first time. The Fc/PEDOT:PSS-PPy is drop coated on the electrode surface as a substrate, and MIP polymers with specific recognition ability are immobilized on the substrate via electrostatic adsorption. As a proof of concept, l-tyrosine (l-Tyr) was selected as a model analyte and the "label-free" mode MIP/Fc/PEDOT:PSS-PPy sensor was constructed. The limit of detection (LOD) and linearity range of the MIP/Fc/PEDOT:PSS-PPy sensor were 2.31 × 10-11 M and from 100 pM to 5 mM, respectively. Compared with the label-like mode, the LOD was three orders of magnitude lower, the linear range was increased by three orders of magnitude, and the sensitivity was improved by more than four times. This work provides a universal and effective concept for MIP electrochemical sensing of amino acids.

Development of a paper-based fluorescent carbon quantum dots MIPs sensor for selective detection of lumpy skin disease virus.

Lumpy skin disease (LSD) is a contagious viral disease caused by the Lumpy Skin Disease virus (LSDV), a member of the Capripoxviridae family. Traditional LSDV diagnostic procedures proved to have challenges in terms of cross reactivity as well as limited sensitivity and specificity. Herein, we combined molecularly imprinted polymers (MIPs) and quantum dots (QDs) technology to develop a paper-based turn on fluorescence sensor for rapid, sensitive and selective detection of LSDV. Under optimal conditions, the sensor showed linear enhancement in fluorescence intensity with the increase of LSDV concentration and exhibited a detection limit of 101 log10 TCID50 per ml. It also presented high specificity towards LSDV compared to other viruses viz sheep pox virus (SPV). Furthermore, the proposed sensor was successfully tested with spiked and real LSDV samples, proving its potential to serve as a sensitive selective sensor for LSDV diagnosis. Based on our knowledge, this is the first record of a paper-based diagnostic sensor for LSDV utilizing a CQDs-MIPs turn-on mechanism.

Targeted microorganism detection with molecularly imprinted polymer biosensors

In this article, a molecularly imprinted polymer (MIP)-based electrochemical biosensor was developed for the detection of Enterococcus faecium, demonstrating exceptional selectivity and sensitivity in real urine samples. Our approach involved fabricating electrodes coated with bacteria-imprinted polypyrrole through electropolymerization. The surface characteristics of the molecularly imprinted polymer (MIP) and non-imprinted polymer (NIP) coated electrodes were thoroughly characterized using cyclic voltammetry and electrochemical impedance spectroscopy. Remarkably, the MIP-coated electrodes exhibited superior conductivity, highlighting their efficacy in capturing Enterococcus faecium. By subjecting the MIP-based biosensor to Enterococcus faecium incubation, we successfully monitored impedance changes, enabling the detection of minute quantities of the bacteria with a limit of detection of 9 CFU/mL. The technology could successfully distinguish Enterococcus faecium from Enterococcus faecalis, a related bacteria species within the same genus, marking a significant advancement in clinical differentiation. Additionally, the biosensor selectively captured Enterococcus faecium and discriminated it from other common bacteria, including Proteus mirabilis, Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. This research underscores the utility of MIP-based electrochemical biosensors for the rapid and selective detection of Enterococcus faecium in clinical settings, with implications for targeted antibiotic therapy and infection control.