Specific Recognition Sites Research Articles

Simultaneous In Vivo Imaging of Neutrophil Elastase and Oxidative Stress in Atherosclerotic Plaques Using a Unimolecular Photoacoustic Probe.

Atherosclerosis, a major global health concern with high morbidity and mortality rates, involves complex interactions of chronic inflammation, oxidative stress, and proteolytic enzymes. Conventional imaging methods struggle to capture the dynamic biochemical processes in atherosclerotic plaques. Here, we introduce a novel unimolecular photoacoustic probe (UMAPP) designed with specific binding sites for neutrophil elastase (NE) and the redox pair O2⋅-/GSH, enabling real-time monitoring of oxidative stress and activated neutrophils in plaques. UMAPP, comprising a boron-dipyrromethene (BODIPY) core linked to a hydrophilic NE-cleavable tetrapeptide and dual oxidative stress-responsive catechol moieties, facilitates NE-mediated modulation of photoinduced electron transfer impacting photoacoustic intensity at 685 nm (PA685). Furthermore, oxidation and reduction of catechol groups by O2⋅- and GSH induce reversible, ratiometric changes in the photoacoustic spectrum (PA745/PA685 ratio). Initial UMAPP applications successfully distinguished atherosclerotic and healthy mice, evaluated pneumonia's effect on plaque composition and verified the probe's effectiveness in drug-treatment studies by detecting molecular alterations before visible histopathological changes. The integrated molecular imaging capabilities of UMAPP offer promising advancements in atherosclerosis diagnosis and management, enabling early and accurate identification of vulnerable plaques.

A fluorescence-validated MIP-ECL sensor based on UiO66 loaded carbon nitride for detection of trace Patulin in series fruit products

Trace-level mycotoxin patulin (PAT) exposure causes serious harm to human health. Herein, a fluorescence (FL)-validated molecularly imprinted polymer (MIP)-electrochemiluminescence (ECL) sensor based on zirconium metal organic frameworks loaded carbon nitride (UiO66@CN) for detection of trace PAT was proposed. UiO66@CN, with abundant-NH2 groups, excellent thermal and aqueous stability compared to CN, was prepared by a simple one-pot method. And it not only has excellent ECL performance, but also has reliable FL visualization properties. MIPs with 3D cavity containing specific PAT recognition sites were imprinted on UiO66@CN modified indium tin oxide by self-polymerization. The binding process of PAT molecules with MIP acted as a gate to control the FL and ECL signals. Notably, visualized FL and sensitive ECL were innovatively implemented in a sensing system. With the help of FL mode validation, PAT was accurately detected in the ECL mode with a detection limit of 50 fg mL−1. In addition, when proposed method and high-performance liquid chromatography (HPLC) were simultaneously applied to fruit products, the results obtained were in complete agreement. Thus, the assay provided a new approach to achieve low-cost, accurate and practical detection of trace toxins.

A Pillar[5]arene-Containing Metal-Organic Framework for Rapid and Highly Capable Adsorption of a Mustard Gas Simulant.

Mustard gas causes irreversible damage upon inhalation or contact with the human body. Consequently, the development of adsorbents for effective interception of mustard gas at low concentrations and high flow rates is an urgent necessity. Here we report a stable porous pillar[5]arene-containing metal-organic framework (MOF) based on zirconium (EtP5-Zr-scu), demonstrating that embedding pillar[5]arene units in MOFs can provide specific binding sites for efficient adsorption of a mustard gas simulant, 2-chloroethyl ethyl sulfide (CEES). EtP5-Zr-scu achieves a higher capacity and more rapid adsorption compared to its counterpart without embedded pillar[5]arene units (H4tcpt-Zr-scu) and perethylated pillar[5]arene (EtP5) alone. Single crystal X-ray diffraction and solid-state nuclear magnetic resonance reveal that the enhanced performance of EtP5-Zr-scu is derived from the host-guest complexation between CEES and pillar[5]arene moieties. Moreover, breakthrough experiments confirmed that the interception performance of EtP5-Zr-scu against CEES (800 ppm, 120 mL/min) was significantly improved (566 min/g) compared with H4tcpt-Zr-scu (353 min/g) and EtP5 (0.873 min/g), attributed to the integration of open channels with specific recognition sites. This work marks a significant advancement in the development of macrocycle-incorporated crystalline framework materials with recognition sites for the efficient capture of guest molecules.

Abstract Or111: Titin cleavage disrupts sarcomere-adhesion tensional homeostasis triggering cardiomyocyte arrhythmia in vitro

The cardiac tissue experiences several forms of mechanical stress, including contraction of cardiomyocytes and forces derived from the stiffness of extracellular matrix (ECM). Preserving homeostatic mechanical forces is crucial for a healthy heart, yet the mechanisms involved are not well-explored. Our study delves into cardiomyocyte responses following the sudden release of mechanical tension across titin, a giant sarcomere protein crucial for setting cardiomyocyte stiffness. Through the expression of virally transduced TEV protease (TEVp) in neonatal mouse cardiomyocytes (NMCMs), we induced the cleavage of mutant titin including the specific TEV protease recognition site (TEVs) within the mechanically active I-band region of the protein. Titin cleavage was validated by 1.8% polyacrylamide SDS-PAGE electrophoresis, revealing a primary band at ~2.2 MDa in TEV-positive NMCMs, corresponding to digested titin fragment A-M. This cleavage, confirmed at 2 days post-infection (dpi) with ~80% efficiency, reached 100% by 5 dpi. Consequently, the Young’s modulus of affected cardiomyocytes dropped by 50%, as determined by Atomic Force Spectroscopy. Sarcomere disarray increased over time, as evidenced by immunofluorescence, yet this effect did not induce cell death or proliferation. Cell viability was confirmed by the fact that affected cardiomyocytes are able to contract spontaneously, although titin cleavage resulted in reduced beating amplitude and induced arrhythmic behavior. Considering this arrhythmogenic situation, we tested cell-cell adhesion through dissociation assays, which revealed significantly reduced intercellular adhesion in affected cardiomyocytes. RNAseq confirmed involvement of pathways related to heart contraction, anchoring junctions, and cell junctions. Specifically, dysregulated genes associated with gap-junction and costamere complexes were observed at 5 dpi. Alterations of adhesion were further confirmed by reductions in connexin 43 and focal adhesion length in immunofluorescence experiments, which also showed mislocalization of important adhesive proteins. In conclusion, titin cleavage in neonatal cardiomyocytes leads to sarcomere disarray, perturbed cell-cell adhesion and arrhythmia. These findings highlight the importance of full mechanical integrity of the titin filament in living cardiomyocytes.

Recent Advances in Synthesising and Applying Magnetic Ion-Imprinted Polymers to Detect, Pre-Concentrate, and Remove Heavy Metals in Various Matrices

Magnetic ion-imprinted polymers (MIIPs) are an innovative material that combines the selectivity of ion imprinting with the ease of separation provided by magnetic properties. Recent advancements in MIIPs have shown that they have higher selectivity coefficients compared to non-imprinted materials. The synthesis of MIIPs involves creating specific recognition sites for target ions in magnetic nanomaterials. Various nanomaterials, such as graphene oxide, carbon nanotubes, and silica, have been incorporated into the IIPs to improve their analytical performance for different environmental applications, including metal extraction, monitoring, detection, and quantification. This review stresses the need to develop new monomers with a high affinity for the target analyte and to find supporting materials with groups that facilitate the effective removal of the target analyte. It also explores the influence of experimental parameters on metal determination.

Imprinted membrane-covalent organic framework platform for efficient label-free visual detection of Listeria monocytogenes and Salmonella typhimurium in food samples

BackgroundRapid and sensitive detection of foodborne pathogens in food plays a crucial role in controlling outbreaks of foodborne diseases, of which Listeria monocytogenes and Salmonella typhimurium are representative and notable pathogens. Thus, it's of great importance to achieve the effective detection of these pathogens. However, the most common detection methods (culture-based technique, Polymerase Chain Reaction and immunological methods) have disadvantages that cannot be ignored, such as time-consuming, laborious, complex sample preparation process, and the possibility of cross-reaction. Hence, it is essential to develop a facile detection method for the pathogens with high sensitivity and specificity to avoid the above-mentioned disadvantages. ResultsWe report a label-free visual platform for the simultaneous capture and detection of Listeria monocytogenes and Salmonella typhimurium. For the first time, we have prepared polydimethylsiloxane-Chromotrope 2R membrane which serves as the substrate for bacterial capture and enrichment through the formation of specific recognition sites. The positively charged Pt-covalent organic framework combines with the pathogens through surface charge interaction, thereby the label-free sandwich platform is formed. Remarkable peroxidase activity of Pt-covalent organic framework converts the conversion of bacterial quantity into amplified color signal by catalyzing 3,3′,5,5′-Tetramethylbenzidine to oxidized 3,3′,5,5′-Tetramethylbenzidine. The platform demonstrates the capability to identify two representative food-borne pathogens within a time frame of 100 min, exhibiting high sensitivity and excellent specificity without the interference from non-target bacteria. The limit of detection of the visual platform toward Listeria monocytogenes and Salmonella typhimurium was 1.61 CFU mL−1 and 1.31 CFU mL−1, respectively. And the limit of quantification toward Listeria monocytogenes and Salmonella typhimurium was 4.94 CFU mL−1 and 2.47 CFU mL−1, respectively. The relative standard derivations of the visual platform for both bacteria were lower than 4.9 %. Furthermore, our proposed platform has obtained reliable and satisfactory results on analyzing diverse food samples. SignificanceThis research expands the application of a label-free platform combined with unlabeled nanocomponents in the rapid isolation and detection of diverse of food-borne pathogens. The platform possesses the advantages of simple operation and real-time monitoring, without complicated sample pretreatment process. The whole detection process can realize the simultaneous monitoring of Listeria monocytogenes and Salmonella typhimurium within 100 min. Furthermore, it is also of reference significance for the detection of other common pathogens.

Covalent triazine framework nanosheets for photo-enhanced uranium extraction

Uranium extraction is the cornerstone of the sustainable development of the nuclear industry. Although a variety of porous framework materials for uranium extraction have been explored over the past few decades, almost all of them have been limited to bulk powder materials. In particular, due to the strong interlayer π-π interaction, the specific recognition sites and photocatalytic active centers of bulk two-dimensional framework materials are severely buried, resulting in the inability to exploit the optimal performance of the materials. In this study, a novel hydroquinone modified covalent triazine frame nanosheets (H-CTF-NSs) is reported for the first time, which is designed for specific extraction and photocatalytic reduction of uranium. The densely distributed hydroquinone and triazine units in the H-CTF-NSs synergistically form high-affinity binding sites, and the ultrathin nanosheets facilitate the exposure of binding sites and catalytically active centers, and accelerate the diffusion of uranyl ions, it is ideally suited as an advanced platform for the selective extraction and efficient reduction of U(VI). Remarkably, H-CTF-NSs demonstrated an unprecedented uranium extraction capacity of 3230.3 mg/g, which is almost 1.71 times that of its bulk counterpart H-CTF, making it one of the best uranium-trapping photocatalysts known to date.

Molecular Memory Micromotors for Fast Snake Venom Toxin Dynamic Detection.

The analysis and detection of snake venom toxins are a matter of great importance in clinical diagnosis for fast treatment and the discovery of new pharmaceutical products. Current detection methods have high associated costs and require the use of sophisticated bioreceptors, which in some cases are difficult to obtain. Herein, we report the synthesis of template-based molecularly imprinted micromotors for dynamic detection of α-bungarotoxin as a model toxin present in the venom of many-banded krait (Bungarus multicinctus). The specific recognition sites are built-in in the micromotors by incubation of the membrane template with the target toxin, followed by a controlled electrodeposition of a poly(3,4-ethylenedioxythiophene)/poly(sodium 4-styrenesulfonate) polymeric layer, a magnetic Ni layer to promote magnetic guidance and facilitate washing steps, and a Pt layer for autonomous propulsion in the presence of hydrogen peroxide. The enhanced fluid mixing and autonomous propulsion increase the likelihood of interactions with the target analyte as compared with static counterparts, retaining the tetramethylrhodamine-labeled α-bungarotoxin on the micromotor surface with extremely fast dynamic sensor response (after just 20 s navigation) in only 3 μL of water, urine, or serum samples. The sensitivity achieved meets the clinically relevant concentration postsnakebite (from 0.1 to 100 μg/mL), illustrating the feasibility of the approach for practical applications. The selectivity of the protocol is very high, as illustrated by the absence of fluorescence in the micromotor surface in the presence of α-cobratoxin as a representative toxin with a size and structure similar to those of α-bungarotoxin. Recoveries higher than 95% are obtained in the analysis of urine- and serum-fortified samples. The new strategy holds considerable promise for fast, inexpensive, and even onsite detection of several toxins using multiple molecularly imprinted micromotors with tailored recognition abilities.

Direct and specific detection of methyl-paraoxon using a highly sensitive fluorescence strategy combined with phosphatase-like nanozyme and molecularly imprinted polymer

Methyl paraoxon (MP) is a highly toxic, efficient and broad-spectrum organophosphorus pesticide, which poses significant risks to ecological environment and human health. Many detection methods for MP are based on the enzyme catalytic or inhibition effect. But natural biological enzymes are relatively expensive and easy to be inactivated with a short service life. As a unique tool of nanotechnology with enzyme-like characteristics, nanozyme has attracted increasing concern. However, a large proportion of nanozymes lack the intrinsic specificity, becoming a main barrier of constraining their use in biochemical analysis. Here, we use a one-pot reverse microemulsion polymerization combine the gold nanoclusters (AuNCs) with molecularly imprinted polymers (MIPs), polydopamine (PDA) and hollow CeO2 nanospheres to synthesize the bright red-orange fluorescence probe (CeO2@PDA@AuNCs-MIPs) with high phosphatase-like activity for selective detection of MP. The hollow structure possesses a specific surface area and porous matrix, which not only increases the exposure of active sites but also enhances the efficiency of mass and electron transport. Consequently, this structure significantly enhances the catalytic activity by reducing transport distances. The introduced MIPs provide the specific recognition sites for MP. And Ce (III) can excite aggregation induced emission of AuNCs and enhance the fluorescent signal. The absolute fluorescence quantum yield (FLQY) of CeO2@PDA@AuNCs-MIPs (1.41 %) was 12.8-fold higher than that of the GSH-AuNCs (0.11 %). With the presence of MP, Ce (IV)/Ce (III) species serve as the active sites to polarize and hydrolyze phosphate bonds to generate p-nitrophenol (p-NP), which can quench the fluorescent signal through the inner-filter effect. The as-prepared CeO2@PDA@AuNCs-MIPs nanozyme-based fluorescence method for MP detection displayed superior analytical performances with wide linearities range of 0.45–125 nM and the detection limit of 0.15 nM. Furthermore, the designed method offers satisfactory practical application ability. The developed method is simple and effective for the in-field detection.

A novel small RNA PhaS contributes to polymyxin B-heteroresistance in carbapenem-resistant Klebsiella pneumoniae

ABSTRACT In recent years, polymyxin has been used as a last-resort therapy for carbapenem-resistant bacterial infections. The emergence of heteroresistance (HR) to polymyxin hampers the efficacy of polymyxin treatment by amplifying resistant subpopulation. However, the mechanisms behind polymyxin HR remain unclear. Small noncoding RNAs (sRNAs) play an important role in regulating drug resistance. The purpose of this study was to investigate the effects and mechanisms of sRNA on polymyxin B (PB)-HR in carbapenem-resistant Klebsiella pneumoniae. In this study, a novel sRNA PhaS was identified by transcriptome sequencing. PhaS expression was elevated in the PB heteroresistant subpopulation. Overexpression and deletion of PhaS were constructed in three carbapenem-resistant K. pneumoniae strains. Population analysis profiling, growth curve, and time-killing curve analysis showed that PhaS enhanced PB-HR. In addition, we verified that PhaS directly targeted phoP through the green fluorescent protein reporter system. PhaS promoted the expression of phoP, thereby encouraging the expression of downstream genes pmrD and arnT. This upregulation of arnT promoted the 4-amino-4-deoxyL-arabinosaccharide (L-Ara4N) modification of lipid A in PhaS overexpressing strains, thus enhancing PB-HR. Further, within the promoter region of PhaS, specific PhoP recognition sites were identified. ONPG assays and RT-qPCR analysis confirmed that PhaS expression was positively modulated by PhoP and thus up-regulated by PB stimulation. To sum up, a novel sRNA enhancing PB-HR was identified and a positive feedback regulatory pathway of sRNA-PhoP/Q was demonstrated in the study. This helps to provide a more comprehensive and clear understanding of the underlying mechanisms behind polymyxin HR in carbapenem-resistant K. pneumoniae.

A molecularly imprinted electrochemical aptasensor-based dual recognition elements for selective detection of dexamethasone

In this work, a novel molecularly imprinted electrochemical aptasensor (MIEAS) was developed for highly selective detection of dexamethasone (Dex) in natural water environment. Gold nanoparticles (AuNPs) modified by nitrogen doped molybdenum carbide-graphene (N–Mo2C-Gr) were employed as the supports, where N–Mo2C-Gr improved the conductivity of the electrode and provided a larger specific surface area to polymerize more active substances. Using Dex as template molecule, o-phenylenediamine (o-PD) as the chemical functional monomer and aptamer as the biofunctional monomer, a molecularly imprinted polymer (MIP) membrane with Dex specific recognition sites was formed by electropolymerization. Due to the synergistic effect of MIP and aptamers, the as-prepared MIEAS exhibited a decent linear relationship to Dex detection within a relatively wide range of 10−13 – 10−5 M, and the detection limit was 1.79 × 10−14 M. The recovery in actual water and tablet samples is satisfactory, which confirms the potential application prospects of this sensor in the determination of Dex.

A molecularly imprinted electrochemiluminescence sensor based on ZnO@CdTe for the detection of mevastatin

In this paper, CdTe quantum dots with near-infrared fluorescence (NIR) and hexagonal prism-shaped ZnO were synthesized, and the composites were characterized for their performance. A sensitive molecularly imprinted electrochemiluminescence (ECL) sensor for the determination of mevastatin was constructed based on ZnO@CdTe and molecularly imprinted polymer (MIP). The highest ECL intensity of the system was obtained by ZnO@CdTe as the main luminophores reacted with the co-reactant K2S2O8. The ECL response generated by the reaction of ZnO@CdTe and K2S2O8 was used as the basic signal detection platform. The MIP was prepared by the electropolymerization process on the above platform, which laid the foundation for forming the mevastatin cavities with specific recognition sites. In addition, the response mechanism was investigated, and the determination conditions were optimized. The ECL intensity change values (ΔI) of the sensor showed a good linear relationship with the logarithm of mevastatin concentration in the range of 2.0 × 10−11 to 2.0 × 10−6 mol L−1, and the limit of detection was 6.7 × 10−12 mol L−1 (S/N = 3). This method obtained satisfactory results in the detection of mevastatin in tablets.

A magnetic imprinted polymer nano-adsorbent with embedded quantum dots and mesoporous carbon for the microextraction of triazine herbicides

A magnetic molecularly imprinted polymer (MMIP) adsorbent incorporating amino-functionalized magnetite nanoparticles, nitrogen-doped graphene quantum dots and mesoporous carbon (MIP@MPC@N-GQDs@Fe3O4NH2) was fabricated to extract triazine herbicides from fruit juice. The embedded magnetite nanoparticles simplified the isolation of the adsorbent from the sample solution. The N-GQDs and MPC enhanced adsorption by affinity binding with triazines. The MIP layer provided highly specific recognition sites for the selective adsorption of three target triazines. The extracted triazines were determined by high-performance liquid chromatography (HPLC) coupled with diode-array detection (DAD). The developed method exhibited linearity from 1.5 to 100.0 µg L−1 with a detection limit of 0.5 µg L−1. Recoveries from spiked fruit juice samples were in the range of 80.1– 108.4 %, with a relative standard deviation of less than 6.0 %. The developed MMIP adsorbent demonstrated good selectivity, high extraction efficiency, ease of fabrication and use, and good stability.

A molecule-imprinted electrochemiluminescence sensor based on CdS@MWCNTs for ultrasensitive detection of fenpropathrin.

A molecularly-imprinted electrochemiluminescence sensor was constructed for the determination of fenpropathrin (FPT) by molecular imprinting technology. In this sensing platform, the introduction of CdS@MWCNTs significantly enhanced the initial ECL signal of the luminol-O2 system. Specifically, MWCNTs was used as a carrier to adsorb more CdS, in which CdS acted as a co-reaction promoter for luminescence. Molecularly imprinted polymer (MIP) containing specific recognition sites of FPT was used as the material for selective recognition. With increasing amount of FPT the ECL signal decreased. Under the optimum conditions, the ECL response was linearly related to the logarithm of FPT concentration. The developed ECL sensor allowed for sensitive determination of FPT and exhibited a wide linear range from 1.0 × 10- 10 mol L- 1 to 1.0 × 10- 6 mol L- 1. The limit of detection was 3.3 × 10- 11 mol L- 1 (S/N = 3). It can be used for the detection of FPT in vegetable samples.

Synthesis of a Multi-Template Molecular Imprinted Bulk Polymer for the Adsorption of Non-Steroidal Inflammatory and Antiretroviral Drugs

In this paper, we report the synthesis of a multi-template molecularly imprinted polymer (MIP) to target and extract naproxen, ibuprofen, diclofenac, emtricitabine, tenofovir disoproxil, and efavirenz from wastewater bodies. A bulk polymerization procedure was used to synthesize the MIP and non-imprinted polymer (NIP). The specific recognition sites for each target were obtained through the removal of the imprinted targeted compounds. The interaction of antiretroviral drugs (ARVs) and non-steroidal anti-inflammatory drugs (NSAIDs) compounds with the MIP was studied under various conditions such as pH, mass, concentration, and time factors. The results demonstrated the optimum conditions were 55 mg of MIP, pH 7.0, a concentration of 5 mg L−1, and a contact time of 10 min. For every compound studied, the extraction efficiencies for ARVs and NSAIDs in aqueous solutions was >96%. The adsorption capacity for the MIP was >0.91 mg·g−1. Adsorption obeys a second-order rate, and the Freundlich model explains the adsorption isotherm data. This study demonstrated that the synthesized multi-template MIP has huge potential to be employed for the removal of ARVs and NSAIDs from the environment as well as in drug purification or recovery processes.

Highly efficient targeted adsorption and catalytic degradation of ciprofloxacin by a novel molecularly imprinted bimetallic MOFs catalyst for persulfate activation

Given the presence of emerging pollutants at low concentrations in water bodies, which are inevitably affected by background substances during the removal process. In this study, we synthesized molecularly imprinted catalysts (Cu/Ni-MOFs@MIP) based on bimetallic metal-organic frameworks for the targeted degradation of ciprofloxacin (CIP) in advanced oxidation processes (AOPs). The electrostatic interaction and functional group binding of CIP with specific recognition sites on Cu/Ni-MOFs@MIP produced excellent selective recognition (Qmax was 14.82 mg g−1), which enabled the active radicals to approach and remove the contaminants faster. Electron paramagnetic resonance (EPR) analysis and quenching experiments revealed the coexistence of ∙OH, SO42−, and 1O2, with ∙OH dominating the system. Based on experimental and theoretical calculations, the reaction sites of CIP were predicted and the possible degradation pathways and mechanisms of Cu/Ni-MOFs@MIP/PMS systems were proposed. This study opens up a new platform for the targeted removal of target pollutants in AOPs.

Alumina inorganic molecularly imprinted polymer modified multi-walled carbon nanotubes for uric acid detection in sweat.

Alumina inorganic molecularly imprinted polymer (MIP) modified multi-walled carbon nanotubes (MWCNTs) on a glassy carbon electrode (MWCNTs-Al2O3-MIP/GCE) was firstly designed and fabricated by one-step electro deposition technique for the detection of uric acid (UA) in sweat. The UA templates were embedded within the inorganic MIP by co-deposition with Al2O3. Through the evaluation of morphology and structure by Field Emission Scanning Electron Microscope (SEM), Energy Dispersive X-ray Spectroscopy (EDS), X-ray Photoelectron Spectroscopy (XPS) and Transmission Electron Microscopy (TEM), it was verified that the specific recognition sites can be fabricated in the electrodeposited Al2O3 molecular imprinted layer. Due to the high selectivity of molecular imprinting holes, the MWCNTs-Al2O3-MIP/GCE electrode demonstrated an impressive imprinting factor of approximately 2.338 compared to the non-molecularly imprinted glassy carbon electrode (MWCNTs-Al2O3-NIP/GCE) toward uric acid detection. Moreover, it exhibited a remarkable limit of detection (LOD) of 50nM for UA with wide detection range from 50nM to 600μM. The MWCNTs-Al2O3-MIP/GCE electrode also showed strong interference resistance against common substances found in sweat. These results highlight the excellent interference resistance and selectivity of MWCNTs-Al2O3-MIP/GCE sensor, positioning it as a novel sensing platform for non-invasive uric acid detection in human sweat.

A novel molecularly imprinted electrochemical sensor from poly (3, 4-ethylenedioxythiophene)/chitosan for selective and sensitive detection of levofloxacin

The improper usage of levofloxacin (LEV) endangers both environmental safety and human public health. Therefore, trace analysis and detection of LEV have extraordinary significance. In this paper, a novel molecularly imprinted polymer (MIP) electrochemical sensor was developed for the specific determination of LEV by electrochemical polymerization of o-phenylenediamine (o-PD) using poly(3,4-ethylenedioxythiophene)/chitosan (PEDOT/CS) with a porous structure and rich functional groups as a carrier and LEV as a template molecule. The morphology, structure and properties of the modified materials were analyzed and studied. The result showed that the electron transfer rate and the electroactive strength of the electrode surface are greatly improved by the interconnection of PEDOT and CS. Meanwhile, PEDOT/CS was assembled by imprinting with o-PD through non-covalent bonding, which offered more specific recognition sites and a larger surface area for the detection of LEV and effectively attracted LEV through intermolecular association. Under the optimized conditions, MIP/PEDOT/CS/GCE showed good detection performance for LEV in a wide linear range of 0.0019– 1000 μM, with a limit of detection (LOD, S/N = 3) of 0.4 nM. Furthermore, the sensor has good stability and selectivity, and exhibits excellent capabilities in the microanalysis of various real samples.

A metal-organic framework-based sensor for specific detection of tetracycline in milk

Molecularly imprinted fluorescent sensors are of interest to researchers due to their specificity, high sensitivity, and stability. In this study, the fluorescence-imprinted sensor (NH2-MIL-53/MIP) for the detection of tetracycline (TC) in animal-derived foods was developed based on the characteristics of luminescent metal-organic frameworks (MOFs) and molecularly imprinted polymers (MIPs). The MOFs provide fluorescence sensing signals and large specific surface areas, while the MIPs provide the specific recognition sites for TC. As a result, the sensor exhibits a wide detection range (0.05–50 μg/mL), high sensitivity (LOD of 0.006 μg/mL), fast detection speed and good selectivity. The sensing principle can be attributed to photoinduced electron transfer. Furthermore, the sensor can determine TC in milk with good recovery rates (95.05–104.71 %). This work addresses the limitation of current molecularly imprinted sensors such as slow corresponding speed and limited detection capability, providing valuable insights for target determination in complex systems.

Fe3O4/biochar modified with molecularly imprinted polymer as efficient persulfate activator for salicylic acid removal from wastewater: Performance and specific recognition mechanism

In this study, a novel Fe3O4-based biochar coupled surface-imprinted polymer was constructed via simple hydrothermal route for salicylic acid recognition and degradation in advanced oxidation processes. The material exhibited excellent adsorption capability, up to 118.23 mg g−1, and efficient degradation performance, 87.44% removal rate within 240 min, based on integrating the advantages of both huge specific surface area as well as abundant functional groups from biochars and specific recognition sites from imprinted cavities. Moreover, high selectivity coefficient (11.67) showed stable recognition in single and binary systems. SO4•− and •OH were confirmed as reactive oxygen species in catalytic reaction according to quenching experiments and EPR analysis. The degradation mechanism and pathway were unraveled by DFT calculations and LC-MS. Furthermore, the results of toxicity evaluation, stability and reusability demonstrated application potential in the field of water environment restoration. This study confirmed that molecular imprinting provided a promising solution to targeted removal of emerging environmental pollutants by degrading after the enrichment of pollutants to the composites surface.