Greenificated Molecularly Imprinted Materials for Advanced Applications

Novel hydrogel pillar array based ratiometric multicolor fluorescence biosensor for visual detection of alkaline phosphatase activity

Enzyme-induced in-situ fluorescence is crucial for the development of biosensing mechanisms and correlative spectroscopic analysis. Inspired by simple p-aminophenol (AP)-controlled synthesis and the specific catalytic reaction of 4-aminophenyl phosphate (APP) triggered by alkaline phosphatase (ALP), our research proposed a strategy to prepare carbon dots (CDs) as fluorescent signals for ALP detection using AP and 3-aminopropyltrimethoxysilane (APTMS) as the precursors. The further constructed ratiometric fluorescence sensor reduced the detection limit of ALP to 0.075 μU/mL by a significant margin. Considering the need for point-of-care testing (POCT), we chose agarose for the preparation of portable hydrogel sensors so that even untrained personnel can quickly achieve semi-quantitative visual detection of ALP using colorimetric cards. These results demonstrate the practical applicability of ratiometric fluorescence sensing hydrogel pillar arrays, which are important for high-sensitivity, visualization, and portable rapid enzyme activity assays.

A smartphone-combined ratiometric fluorescence molecularly imprinted probe based on biomass-derived carbon dots for determination of tyramine in fermented meat products

A ratiometric fluorescence molecularly imprinted probe employing two distinct emission wavelengths of biomass carbon dots was developed for highly selective and visual quantitative detection of tyramine in fermented meat products. The red emission biomass carbon dots were employed as responsive elements, and the blue ones were utilized as the reference elements. The molecularly imprinted polymers were incorporated in the ratiometric sensing to distinguish and adsorb tyramine. With the linear range of 1-60 μg/L, the ratiometric fluorescence molecularly imprinted probe was successfully applied to detect tyramine in real samples with the satisfactory recoveries of 79.74-112.12% and the detect limitation of 1.3 μg/kg, indicating that this probe has great potential applications for the detection of tyramine in real samples. Moreover, smartphone-based fluorescence signal recognition analysis on hand has been developed for the quantitative analysis of tyramine, providing a portable visual optical analysis terminal for rapid on-site determination of tyramine.

Construction of a monoclonal molecular imprinted sensor with high affinity for specific recognition of influenza a virus subtype

Although molecular imprinting technology has been widely used in the construction of virus sensors, it is still a great challenge to identify subtypes viruses specifically because of their high similarity in morphology, size and structure. Here, a monoclonal molecular imprinted polymers (MIPs) sensor for recognition of H5N1 is constructed to permit the accurate distinguishing of H5N1 from other influenza A virus (IAV) subtypes. Firstly, H5N1 are immobilized on magnetic microspheres to produce H5N1-MagNPs, then the high affinity nanogel H5N1-MIPs is prepared by solid phase imprinting technique. When H5N1-MIPs is combined with MagNP-H5N1, different concentrations of H5N1 are added for competitive substitution. The quantitative detection of H5N1 is realized by the change of fluorescence intensity of supernatant. As expected, the constructed sensor shows satisfactory selectivity, and can identify the target virus from highly similar IAV subtypes, such as H1N1, H7N9 and H9N2. The sensor was highly sensitive, with a detection limit of 0.58 fM, and a selectivity factor that is comparable to that of other small MIPs sensors is achieved. In addition, the proposed sensor is cheap, with a cost of only RMB 0.08 yuan. The proposed monoclonal sensor provides a new method for the specific recognition of designated virus subtype, which is expected to be used for large-scale screening and accurate treatment of infected people.

Molecularly imprinted electrochemical sensor for ethyl carbamate detection in Baijiu based on "on-off" nanozyme-catalyzing process

Ethyl carbamate (EC) is a carcinogen widely found in the fermentation process of Baijiu. Herein, we construct a molecularly imprinted polymers/MXene/cobalt (II) based zeolitic imidazolate frameworks (MIP/MXene/ZIF-67) nano-enzyme sensor for the detection of EC during Baijiu production. The ZIF-67 is synthesized in situ on the MXene nanosheets to provide a superior catalytic activity to H2O2 and amplify the electrochemical signal. The MIP is prepared by the polymerization reaction to recognize EC. Owing to the interaction between EC and EC-MIP, the interferences are effectively eliminated, greatly improving the accuracy of the expected outcome. This approach attains an ultrasensitive assay of EC ranging from 8.9 μg/L to 44.5 mg/L with detection limit of 0.405 μg/L. The accuracy of this method is confirmed by the recovery experiment with good recoveries from 95.07% to 107.41%. This method is applied in natural EC analyses, and the results are consistent with certified gas chromatograph- mass spectrometer.

Bio(sensors) based on molecularly imprinted polymers and silica materials used for food safety and biomedical analysis: Recent trends and future prospects

In recent decades, analytical techniques have increasingly focused on the precise quantification. Achieving this goal has been accomplished with conventional analytical approaches that typically require extensive pretreatment methods, significant reagent usage, and expensive instruments. The need for rapid, simple, and highly selective identification platforms has become increasingly pronounced. Molecularly imprinted polymer (MIP) has emerged as a promising avenue for developing advanced sensors that can potentially surpass the limitations of conventional detection methods. In recent years, the application of MIP-silica materials-based sensors has garnered significant attention owing to their distinctive characteristics. These types of probes hold a distinct advantage in their remarkable stability and durability, all of which provide a suitable sensing platform in severe environments. Moreover, the substrate composed of silica materials offers a vast surface area for binding, thereby facilitating the efficient detection of even minuscule concentrations of targets. As a result, sensors based on MIP-silica materials have the potential to be widely applied in various industries, including medical diagnosis, and food safety. In the present review, we have conducted an in-depth analysis of the latest research developments in the field of MIPs-silica materials based sensors, with a focus on succinctly summarizing and elucidating the most crucial findings. This is the first comprehensive review of integration MIPs with silica materials in electrochemical (EC) and optical probes for biomedical analysis and food safety.

Constructing molecularly imprinted membranes with instant noodles-like structure for selectively separating acteoside

Acteoside (ACT) was the main bioactive components in phenylethanoid glycosides of Cistanche tubulosa. Currently, the development of an efficient method for selectively separating ACT was crucial. Consequently, yolk-shell magnetic mesoporous carbon (YSMMC) was synthesized as a nanofiller to prepare molecularly imprinted membranes (ACT-MIMs) with instant noodles-like structure for selectively separating ACT. The numerous YSMMC were moved to the upper surface of ACT-MIMs by magnetic guidance and constructed the instant noodles-like structure in ACT-MIMs. The instant noodle-like structure increased the surface roughness of ACT-MIMs, which was conducive to improving the effective imprinted interface, increasing the selectivity of ACT-MIMs. In addition, the instant noodle-like structure had dendritic interleaved pathways in ACT-MIMs. The dendritic interleaved pathways can intercept ACT through ACT-MIMs, enhancing the permselectivity of ACT-MIMs. The prepared YSMMC possessed the dendritic shell and interlayer cavity structure can provide a great accommodation space, improving the rebinding capacities of ACT-MIMs. The high permselectivity (14.49), remarkable selectivity (7.52), and excellent rebinding capacity (120.48 mg/g) were achieved for the prepared ACT-MIMs. Thus, the design of ACT-MIMs with the instant noodles-like structure were valuable for selectively separating of bioactive components.

Nitrogen-doped magnetic porous carbon nanospheres derived from dual templates-induced mesoporous polydopamine coated Fe3O4 for efficient extraction and sensitive determination of volatile nitrosamines by gas chromatography-mass spectroscopy

N-nitrosamines (NAs) are highly carcinogenic compounds commonly found in food, beverages, and consumer products. Due to their wide polarity range, it is challenging to find a suitable carbon adsorbent that can simultaneously adsorb and enrich both polar and nonpolar NAs with good recovery. In this study, nitrogen-doped magnetic mesoporous carbon nanospheres (M-MCN) were prepared and employed as an adsorbent for magnetic solid-phase extraction (MSPE) to extract and concentrate four NAs. The introduction of nitrogen functional groups enhanced the hydrophilicity of the carbon material, allowing M-MCN to achieve a balance between hydrophilicity and hydrophobicity, resulting in good recovery for both polar and nonpolar NAs. A method combining MSPE with gas chromatography-mass spectrometry (GC-MS) was developed for the determination of NAs in processed meat and alcoholic beverages. The method exhibited a good linear range (1-100 ng g-1, r2 > 0.9967) and trace-level detection (0.53-6.6 ng g-1). The recovery rates for the four NAs ranged between 85.7 and 110.7 %, with intra-day precision expressed as relative standard deviation (RSD) between 4.1 and 10.7 %, and inter-day precision between 4.8 and 12.9 %. The results demonstrated not only good accuracy and precision but also provided a new adsorbent for the enrichment of trace-level NAs in processed meat and alcoholic beverage samples.

Surface molecularly imprinted polymer/covalent organic framework/silica composite material with specific recognition ability and excellent chromatographic performance

Facing with the difficulty of specific chromatographic separation of nucleoside drugs, this study prepared a surface molecularly imprinted polymer (SMIP) modified covalent organic framework (COF) coated silica stationary phase based on the specificity of molecular imprinting technology and the powerful chromatographic separation performance of COF. This novel SMIP-COF@SiO2 stationary phase can not only specifically identify template molecule and structural analogs, but can also be used to separate multiple types of analytes, such as B vitamins, sulfonamides, alkylbenzenes, phenyl ketones, polycyclic aromatic hydrocarbons and environmental endocrine disruptors, which satisfies the need for complex sample separation. Various retention mechanisms have been investigated and multiple interactions between the SMIP-COF@SiO2 stationary phase and the analytes are discovered. The chromatographic performance of SMIP-COF@SiO2 is far superior to that of the SMIP@SiO2 and COF@SiO2. Furthermore, the SMIP-COF@SiO2 stationary phase can be successfully used to analyze polycyclic aromatic hydrocarbons in the environmental water sample and detect whitening ingredient in skincare product, indicating its great potential for application in various fields.

Solvent and monomer regulation synthesis of core-shelled magnetic β-cyclodextrin microporous organic network for efficient extraction of estrogens in biological samples prior to HPLC analysis

The abnormal estrogens levels in human body can cause many side effects and diseases, but the quantitative detection of the trace estrogens in complex biological samples still remains great challenge. Here we reported the fabrication of a novel core-shell structured magnetic cyclodextrin microporous organic network (Fe3O4@CD-MON) for rapid magnetic solid phase extraction (MSPE) of four estrogens in human serum and urine samples prior to HPLC-UV determination. The uniform spherical core-shell Fe3O4@CD-MONs was successfully regulated by altering the reactive monomers and solvents. The Fe3O4@CD-MONs owned high specific surface area, good hydrophobicity, large superparamagnetism, and abundant extraction sites for estrogens. Under optimal conditions, the proposed MSPE-HPLC-UV method provided wide linearity range (2.0-400 μg L-1), low limits of detection (0.5-1.0 μg L-1), large enrichment factors (183-198), less adsorbent consumption (3 mg), short extraction time (3 min), and good stability and reusability (at least 8 cycles). The established method had also been successfully applied to the enrichment and detection of four estrogens in serum and urine samples with a recovery of 88.4-105.1 % and a relative standard deviation of 1.0-5.9 %. This work confirmed the feasibility of solvent and monomer regulation synthesis of Fe3O4@CD-MON composites, and revealed the great prospects of magnetic CD-MONs for efficient enrichment of trace estrogens in complex biological samples.

Molecularly imprinted Ag2S quantum dots with high photocatalytic activity for dye removal: Experimental and DFT insights

Molecular imprinted polymers (MIPs) were developed by carrying out the cocktail solution of Template ((Salata, 2004)-Gingerol), monomer, crosslinker, and Ag2S Quantum Dots (QDs) by ex-situ dissolved in an appropriate solvent, resulting in an efficient crosslinked polymer composite. Degradation of Alizarin red S (ARS) dye and yellowish sunset (SY) azo dye under visible light irradiation was reported first time by the introduction of prepared MIPs composite. In this research, the result shows efficient photocatalyt activity of Ag2S-MIPs composite for the degradation of AR and SY dye with degradation% (80%) and (84%) in the aqueous wastewater. The degradation efficiency of the Ag2S-MIPs composite and the Ag2S QD associated with non-imprinted polymers (NIPs) (i.e.Ag2S-NIPs composite) were calculated by using different parameters such as catalyst dose, pH value, optimum time and concentration variation and the observations are evocative. Moreover, the density functional theory (DFT) approach was also used to analyze the structural, stability/energetics, and electronic features of the organic-inorganic hybrid composites of the Ag2S QD with the MIPs based on (Salata, 2004)-gingerol extract. The proposed QD and MIPs (EGDMA and (Salata, 2004)-Gingerol) composite model has been detected to be the most stable because it shows the largest binding energy (BE) among the three chosen composite models. It was found out that imprinted polymers were superior in enhancing the degradation of dyes when compared to non imprinted polymers. Introducing MIPs into the valence band accelerates the catalysis properties to stabilize newly fashioned excitons that are basically generated as a result of light excitation in presence of Ag2S Quantum Dots (QDs) and molecular imprinted polymer (MIPs). Motivation behind this work is to address the challenges related to environmental pollution causing by organic dyes. These toxins are known to cause diverse symptoms (e.g., skin irritation, eye infection, respiratory disorders, and even cancer) once exposed through ingestion and inhalation. Through incorporation of Ag2S QD into MIP,the purpose of this research is to enhance the selectivity, specificity and photocatalytic activity for dyes and that work holds a potential towards environmental remediation by developing a cost effective and sustainable method for controlling pollution in water.

Utilizing electrospun molecularly imprinted membranes for food industry: Opportunities and challenges

Molecularly imprinted polymers (MIPs) have been widely studied in environmental protection and food industry, owing to their excellent specific recognition and structural stability. However, MIPs prepared by conventional methods suffer from low adsorption capacity and slow mass transfer rate. To date, the combination of electrostatic spinning technology and molecular imprinting technology has been proposed to prepare molecularly imprinted membranes (MIMs) with specific recognition capability, and has shown great attraction in the separation and detection of food additives, as well as the extraction and release of active ingredients. In recent years, MIPs and electrostatic spinning technologies have been investigated and evaluated. However, there is no review of electrostatically spun MIMs for food field. In this review, we focus on the fabrication methods and applications of electrostatically spun MIMs in the food, discuss the challenges in practical food applications, and emphasize the promising applications of electrostatically spun MIMs in food field.

Site-specific immobilization of Cysteinyl leukotriene receptor 1 through enzymatic DNA-protein conjugation strategy for lead screening

Immobilization of functional protein, especially G protein-coupled receptors (GPCRs), is particularly significant in various fields such as the development of assays for diagnosis, lead compound screening, as well as drug-protein interaction analysis. However, there are still some challenges with the immobilized proteins such as undefined loads, orientations, and the loss of activity. Herein, we introduced a DNA conjugation strategy into the immobilization of Cysteinyl leukotriene receptor 1(CysLTR1) which enables exquisite molecular control and higher activity of the receptor. We used the bacterial relaxases VirD2 as an immobilized tag fused at the C terminus of CysLTR1. Tyrosine residue(Y29) at the core binding site of the VirD2 tag can react with the single-strand piece of DNA(T-DNA) in the form of a covalent bond. Inspired by this strategy, we developed a new immobilization method by mixing the T-DNA-modified silica gel with the cell lysate containing the expressed VirD2-tagged CysLTR1 for 1 hour. We found that the successful formation of DNA-protein conjugate enables the immobilization of CysLTR1 fast, site-specific, and with minimal loss of activity. The feasibility of the immobilized CysLTR1 was evaluated in drug-protein binding interaction by frontal analysis and adsorption energy distribution analysis. The binding of pranlukast, zafirlukast, and MK571 to the immobilized CysLTR1 was realized, and the association constants presented good agreement between the two methods. Rosmarinic acid was retained in the immobilized CysLTR1 column, and the in-vitro test revealed that the compound binds to the receptor in one type of binding site mode. Despite these results, we concluded that the DNA-protein conjugate strategy will probably open up the possibilities for capturing other functional proteins in covalent and site-specific modes from the complex matrices and the immobilized receptor preserves the potential in fishing out lead compounds from natural products.

Recent advances in molecularly imprinted polymers (MIPs) for visual recognition and inhibition of α-dicarbonyl compound-mediated Maillard reaction products

α-Dicarbonyl compounds (α-DCs) are important intermediates and precursors of harmful Maillard reaction products (e.g., acrylamide and late glycosylation end-products), and they exist widely in thermoprocessed sugar- or fat-rich foods. α-DCs and their end-products are prone to accumulation in the human body and lead to the development of various chronic diseases. Therefore, detection of α-DCs and their associated hazards in food samples is crucial. This paper reviews the preparation of molecularly imprinted polymers (MIPs) enabling visual intelligent responses and the strategies for recognition and capture of α-DCs and their associated hazards, and provides a comprehensive summary of the development of visual MIPs, including integration strategies and applications with real food samples. The visual signal responses as well as the mechanisms for hazard recognition and capture are highlighted. Current challenges and prospects for visual MIPs with advanced applications in food, agricultural and environmental samples are also discussed. This review will open new horizons regarding visual MIPs for recognition and inhibition of hazards in food safety.

Carbonized polymer dots-based molecular imprinting: An adsorbent with enhanced selectivity for highly efficient recognition and removal of ceftiofur sodium from complex samples

Highly selective removal of residual cephalosporin antibiotics from complex systems is crucial for human health and ecological environment protection. Herein, a newly molecularly imprinted polymer adsorbent (CPDs-NH2@MIP) with enhanced selectivity for ceftiofur sodium (CTFS) was developed by using the special carbonized polymer dots (CPDs-NH2) as functional monomer. The CPDs-NH2 has a nano-spherical structure and functionalized groups (CC, -NH2) via the incomplete carbonization polymerization of citric acid, acrylamide and ethylenediamine, which can accurately interact with CTFS by overcoming steric hindrance, resulting in more precisely imprinted sites and reducing non-imprinted regions in MIP. The presented CPDs-NH2@MIP exhibited excellent adsorption capacity for CTFS (68.62 mg g-1), achieving equilibrium within 10 min, and highly selectivity in mixed solution containing five coexisting substances, with an imprinted factor (5.61). Compared with commercial adsorbents and MIPs prepared with traditional chain functional monomers, the CPDs-NH2@MIP showed significant advantage in selective recognition and separation of target. Analysis of microstructure and mechanism proved that usage of the spherical functional monomer generated precise imprinting sites and dense structure in CPDs-NH2@MIP, which effectively enhanced the selectivity in complex system combined with hydrogen bonding interaction. The idea of designing and using spherical functional monomer will promote the practicality of molecularly imprinted polymer adsorbents.

Advancements and greenification potential of magnetic molecularly imprinted polymers for chromatographic analysis of veterinary drug residues in milk

Milk, as a widely consumed nutrient-rich food, is crucial for bone health, growth, and overall nutrition. The persistent application of veterinary drugs for controlling diseases and heightening milk yield has imparted substantial repercussions on human health and environmental ecosystems. Due to the high demand, fresh consumption, complex composition of milk, and the potential adverse impacts of drug residues, advanced greener analytical methods are necessitated. Among them, functional materials-based analytical methods attract wide concerns. The magnetic molecularly imprinted polymers (MMIPs), as a kind of typical functional material, possess excellent greenification characteristics and potencies, and they are easily integrated into various detection technologies, which have offered green approaches toward analytes such as veterinary drugs in milk. Despite their increasing applications and great potential, MMIPs' use in dairy matrices remains underexplored, especially regarding ecological sustainability. This work reviews recent advances in MMIPs' synthesis and application as efficient sorbents for veterinary drug extraction in milk followed by chromatographic analysis. The uniqueness and effectiveness of MMIPs in real milk samples are evaluated, current limitations are addressed, and greenification opportunities are proposed. MMIPs show promise in revolutionizing green analytical procedures for veterinary drug detection, aligning with the environmental goals of modern food production systems.

Development and Application of a Selective Analytical Method for Indole Metabolites in Urine: Dietary Exposure Biomarkers for Broccoli Consumption

The identification of dietary exposure biomarkers is crucial for advancing our understanding of the health benefits of specific foods. Broccoli, a vegetable with well-known anticancer properties, contains active ingredients, such as isothiocyanates with indole side chains. Hence, indole metabolites related to broccoli consumption have the potential to serve as biomarkers of dietary exposure. In this work, we developed a new analytical method for indole metabolites in urine using a poly(deep eutectic solvents)-molecularly imprinted polymer/vinyl-functionalized graphene oxide (PDESs-MIP/VGO) in miniaturized centrifugal pipet-tip solid-phase extraction (CPT-SPE) coupled with liquid chromatography. This method integrates the strengths of PDESs-MIP/VGO, including rich adsorption interactions, high adsorption capacity, and excellent selectivity, with the simplicity and cost-effectiveness of CPT-SPE. The proposed method demonstrated low limits of quantification (1.2-2.5 ng mL-1), high accuracy (91.7-104.8%), and good precision (relative standard deviation ≤4.4%). By applying this method to analyze indole metabolites in urine, our results suggested that indole-3-carbinol and indole-3-acetonitrile have the potential to emerge as reliable dietary exposure biomarkers for broccoli intake. Furthermore, highly selective analytical methods based on molecular imprinting technology are advantageous for precise screening and analysis of dietary exposure biomarkers associated with food consumption.

Portable tri-color ratiometric fluorescence paper sensor for intelligent visual detection of dual-antibiotics and aluminium ion

The toxicological effect between co-existed antibiotics and metal ions was dangerous to the ecological environment and public health. However, the rapid quantification tools with convenience, accuracy and low cost for the detection of multiple targets were still challenging. Herein, a portable tri-color ratiometric fluorescence paper sensor was constructed by coupling of blue carbon dots and fluorescence imprinted polymer for down/up conversion simultaneous detection of tetracycline and sulfamethazine. Interestingly, the cascade detection of aluminum ion was also realized based on the individual detection system of tetracycline without the assistance of complex coupling reagents. The detection limits of smartphone method for the visual detection of tetracycline, sulfamethazine and aluminum ion were calculated as 0.014 μM, 0.004 μM and 0.019 μM, respectively. The portable fluorescence paper sensor was applied for the visual detection of tetracycline, sulfamethazine and aluminum ion in actual samples successfully with satisfactory recoveries. With the advantages of rapidness, low cost, and portability, the developed portable fluorescence paper sensor provided a new strategy for the visual real-time detection of multiple targets.

A new multi-template molecularly imprinted polymer for separation and purification of dioscin, protodioscin, and diosgenin from purple yam

Saponin is an essential natural compound in purple yams with high nutritional and medicinal value. In this work, a multitemplate molecule-imprinted polymer (MMIP) was synthesized with dioscin, protodioscin, and diosgenin templates. The MMIPs were characterized with scanning electron microscopy, thermogravimetric analysis, Brunauer-Emmett-Teller (BET) adsorption, and Fourier transform infrared spectroscopy. The efficacy of the MMIPs was assessed with static, dynamic, selective adsorption, desorption, and reusability experiments. The three saponins were selectively extracted and determined by MMIP-high-performance liquid chromatography. The polymer morphology was regular and spherical. The amount of the MMIP adsorbed was 74.825 mg/g, and the imprinting factor was 2.1. The MMIP adsorbed the three saponins from purple yam extract, with recovery rates of 95.5-103.43 % and desorption rates of 85 %-98 %. In addition, the MMIPs were reused at least six times. These results demonstrated that the MMIPs efficiently and selectively extracted dioscin, protodioscin, and diosgenin from food matrices at high rates.

Carbon-dots encapsulated luminescent metal-organic frameworks@surface molecularly imprinted polymer: A facile fluorescent probe for the determination of chloramphenicol

In this study, carbon dots (CDs)-encapsulated luminescent metal-organic frameworks@surface molecularly imprinted polymer (CDs@MOF@SMIP) was facilely prepared and applied as fluorescent probe for specific identification and sensitive detection of chloramphenicol (CAP) in food. Fluorescent CDs, serving as signal tags, were encapsulated within metal-organic backbones (ZIF-8), yielding luminescent MOF materials (CDs@ZIF-8). The synthesized CDs, CDs@ZIF-8 and CDs@ZIF-8@SMIP were investigated by morphological and structural characterizations (UV-Vis, XRD, FT-IR, BET, TEM). The CDs@ZIF-8@SMIP probe was demonstrated to have remarkable selectivity and sensitivity towards CAP. Its fluorescence decreased linearly with CAP concentration from 0.323 μg L-1 (0.001 μM) to 8075.0 μg L-1 (25.0 μM), featuring a low detection limit of 0.08 μg L-1. The CDs@ZIF-8@SMIP-based fluorescence strategy achieved satisfactory recoveries (95.5 % - 101.0 %) in CAP-spiked commercial foods with RSD < 4.4 % (n = 3). These results indicate that this method can effectively detect trace CAP in food matrices and has broad application prospects.

Hydrophilic molecularly imprinted lysozyme-BiOBr composite with enhanced visible light utilization for selective removal of trace contaminants in water

The development of high-efficiency molecularly imprinted photocatalysts is still challenging due to the lack of hydrophilic and suitable functional monomers. In this work, the bio-sourced lysozyme was developed as the hydrophilic functional monomer, and Cu-doped BiOBr was used as the photocatalysts, to prepare a novel hydrophilic molecularly imprinted lysozyme-BiOBr composite (BiOBr-Cu/LyzMIP) with enhanced visible light utilization. Lysozyme could form a transparent layer to mitigate the light transmission obstruction caused by the surface imprinting layer, making it an ideal functional monomer. The prepared BiOBr-Cu/LyzMIP possessed red-shifted visible-light absorption edge and minor reduction of light absorbance, indicating the enhanced utilization of visible light. Accordingly, BiOBr-Cu/LyzMIP demonstrated excellent degradation rate (99.4 % in 20 min), exceptional degradation efficiency (0.211 min-1), and superior reusability. Moreover, BiOBr-Cu/LyzMIP exhibited rapid adsorption equilibrium (20 min), good imprinting factor (2.67), and favourable degradation selectivity (>1.75), indicating the good imprinting effect resulting from abundant functional groups of lysozyme. Versatility experiments on different templates suggested that the proposed approach allowed flexibility in selecting a wide range of hazardous contaminants according to practical requirements. The present work expands the application of lysozyme-based composites in the environmental field, and provides a new one-stop pathway for efficient and sustainable treatment of contaminated water.

A two-dimensional iron-doped carbon-based nanoenzyme with catalase-like activity for the detection of alkaline phosphatase and ascorbate oxidase

Herein, we successfully synthesized two-dimensional iron-doped carbon-based nanosheets (Fe-N800 CS) with catalase-like activity through doping Fe into Zn MOF and introducing graphitic C3N4 (g-C3N4). The interaction of the Fe-N800 CS with hydrogen peroxide could generated abundant reactive oxygen species (ROS) and further oxidize o-Phenylenediamine (OPD) to 2,3-diaminophenazine (DAP) which has constant fluorescence at 560 nm. Ascorbic acid (AA) could be generated via the hydrolysis reaction between alkaline phosphatase (ALP) and ascorbic acid 2-phosphate (AAP). AA can be oxidized to dehy-droascorbic acid (DHA) by ROS, and then combined with OPD to generate 3-(1,2-dihydroxyethyl)furo[3,4b]-quinoxaline (QXD) with fluorescence at 440 nm, which could increase as the concentration of AA enhanced. DHA could also be generated through oxidation of AA by ascorbate oxidase (AAO). Thus, by monitoring the fluorescence ratio (I560/I440), a ratiometric fluorescence biosensing platform for ALP and AAO was established with the linear ranges in 0.2-10 U/L and 1-60 U/L, respectively. The limit of detection for ALP and AAO were 0.12 U/L and 0.59 U/L. Furthermore, the biosensing platform was successfully applied for the detection of ALP and AAO activity in human serum samples. This work provides a potential tool for future biomedical diagnostics.

Preparation of novel gallic acid-based dummy-template molecularly imprinted polymer adsorbents for rapid adsorption of dibutyl phthalate from water

Phthalate esters (PAEs) are plasticizers widely used in the industry and easily released into the environment, posing a serious threat to human health. Molecularly imprinted polymers (MIPs) are important as selective adsorbents for the removal of PAEs. In this study, three kinds of mussel-inspired MIPs for the removal of PAEs were first prepared with gallic acid (GA), hexanediamine (HD), tannic acid (TA), and dopamine (DA) under mild conditions. The adsorption results showed that the MIP with low cost derived from GA and HD (GAHD-MIP) obtained the highest adsorption capacity among these materials. Furthermore, 97.43% of equilibrium capacity could be reached within the first 5 min of adsorption. Especially, the dummy template of diallyl phthalate (DAP) with low toxicity was observed to be more suitable to prepare MIPs than dibutyl phthalate (DBP), although DBP was the target of adsorption. The adsorption process was in accordance with the pseudo-second-order kinetics model. In the isotherm analysis, the adsorption behavior agreed with the Freundlich model. Additionally, the material maintained high adsorption performance after 7 cycles of regeneration tests. The GAHD-MIP adsorbents in this study, with low cost, rapid adsorption equilibrium, green raw materials, and low toxicity dummy template, provide a valuable reference for the design and development of new MIPs.

A sensitive fluorometric-colorimetric dual-mode intelligent sensing platform for the detection of formaldehyde

Excess formaldehyde (FA) is a strong carcinogen, so the development of a rapid visualized and portable formaldehyde detection platform is of great research importance. A multi-color fluorescence sensing system constituted of model compound (NAHN) and red-emitting InP/ZnS QDs was constructed herein, which can simultaneously realize fluorometric-colorimetric dual-mode sensing when exposed to FA environment. Its preparation process was simplified, the detection process was green, and the limits of detection (LOD) were 0.623 μM and 0.791 μM, respectively. The high recoveries of FA in actual water samples indicated that the sensor had broad application prospects. The prepared fluorescent film can be utilized for rapid visual simulation analysis of FA on the surface of various fruits and vegetables. In addition, a serial logic gate was designed to quickly semi-quantitatively assess FA concentration, which promoted the realization of on-site intelligent evaluation of FA.

In vivo treatment of zinc phosphide poisoning by administration of mesoporous silica nanoparticles as an effective antidote agent

Mesoporous silica nanoparticles (MSNs) are highly advanced engineered particles with increased surface area and extreme adsorption capacity for various molecules. Herein, two types of MSNs were synthesized and applied as adsorbents for phosphine gas. One was without functional groups (MSN), and the other was post-modified with boric acid (MSN-BA). The structures of MSN and boric acid-modified MSN with high surface areas of about 1025 and 650 m2/g, respectively, were defined. MSN was found to have particles with sizes around 30 nm by transmission electron microscopy (TEM). In the present study, MSNs were used as an antidote to phosphorus poisoning, and zinc phosphide (phosphorus) powder was used as the toxic and lethal agent. In vivo analysis was carried out on rats to demonstrate the ability of MSNs to chemisorb phosphine gas. In the survival percentage assessment, Phos-poisoned animals were kept alive after treatment with MSNs, and the MSN-BA-treated group (dose of 5 mg/kg) was shown to have a 60 % survival rate. Blood serum analysis showed that MSNs have a high potential to alleviate organ blood damage, and serum biomarkers dropped sharply while phosphine-poisoned animals were treated with MSN-BA.

Application of a novel deep eutectic solvent modified carbon nanotube for pipette-tip micro solid phase extraction of 6-mercaptopurine

BACKGROUND

6-mercaptopurine (6-MP) is a chemotherapy drug mainly used to treat leukemia. It is a persistent organic pollutant and can remain in the environment for a long period of time. The presence of 6-MP in the environment poses a number of hazards and needs to be assessed to monitor its potential risk to human health and the environment. However, due to its trace amount in complicated matrices, a clean-up and preconcentration step before its determination is compulsory.

RESULTS

As a highly efficient adsorbent for the extrication of 6-mercaptopurine (6-MP), a novel carbon nanotube doped with camphor: decanoic acid deep eutectic solvent was synthesized and applied as a packing material for the pipette-tip micro solid phase extraction sorbent of 6-MP from tap, wastewater and seawater samples before its spectrophotometric determination. Characteristics and structure of this adsorbent was fully investigated. Factors affecting extraction, including type and volume of the eluent, ionic strength and pH of the sample solution, amount of adsorbent, and number of extraction and elution cycles were optimized using one-factor-at-a-time and response surface methodologies. The method was found to be linear in the range of 1 to 1000 µg/L with a limit of detection and quantification of 0.2 and 0.7 µg/L, respectively. Reproducibility as relative standard deviation was better than 4.6%.

CONCLUSION

Application of deep eutectic solvent modified carbon nanotube indicated suitable microextraction results and good potential for rapid extraction of trace amounts of 6-MP from different aqueous samples. The amount of sample required for the analysis was less than 10 mL and only 1.5 mg of the adsorbent was used. The total analysis time, including extraction was less than 15 min and the adsorbent could be used for at least 10 times, without significantly losing its adsorption ability. Compared to using unmodified usual carbon nanotubes, deep eutectic solvent doped carbon nanotubes showed 19.8% higher extraction ability.

Molecular Imprinting-Based SERS Detection Strategy for the Large-Size Protein Quantitation and Curbing Non-Specific Recognition

Molecular imprinting-based surface-enhanced Raman scattering (MI-SERS) sensors have shown remarkable potential from an academic standpoint. However, their practical applications, especially in the detection of large-size protein (≥10 nm), face challenges due to the lack of versatile sensing strategies and nonspecific fouling of matrix species. Herein, we propose a Raman reporter inspector mechanism (RRIM) implemented on a protein-imprinted polydopamine (PDA) layer coated on the SERS active substrate. In the RRIM, after large-size protein recognition, the permeability of the PDA imprinted cavities undergoes changes that are scrutinized by Raman reporter molecules. Target proteins can specifically bind and fully occupy the imprinted cavities, whereas matrix species cannot. Then, Raman reporter molecules with suitable size are introduced to serve as both inspectors of the recognition status and inducers of the SERS signal, which can only penetrate through the vacant and nonspecifically filled cavities. Consequently, changes in the SERS signal exclusively originate from the specific binding of target proteins, while the nonspecific recognition of matrix species is curbed. The RRIM enables reproducible quantitation of the large-size cyanobacteria-specific protein model (≥10 nm), phycocyanin, at the level down to 2.6 × 10-3 μg L-1. Finally, the practical applicability of the RRIM is confirmed by accurately analyzing crude urban waterway samples over 21 min without any pretreatment.

Graphene quantum dots on TiO2 nanotubes as a light-assisted peroxidase nanozyme

Hybrid nanozyme graphene quantum dots (GQDs) deposited TiO2 nanotubes (NTs) on titanium foil (Ti/TiO2 NTs-GQDs) were manufactured by bestowing the hybrid with the advantageous porous morphology, surface valence states, high surface area, and copious active sites. The peroxidase-like activity was investigated through the catalytic oxidation of chromogenic substrate 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2, which can be visualized by the eyes. TiO2 NTs and GQDs comprising oxygen-containing functional groups can oxidize TMB in the presence of H2O2 by mimicking peroxidase enzymes. The peroxidase-mimicking activity of hybrid nanozyme was significantly escalated by introducing light illumination due to the photosensitive features of the hybrid material. The peroxidase-like activity of Ti/TiO2 NTs-GQDs enabled H2O2 determination over the linear range of 7 to 250 μM, with a LOD of 2.1 µM. The satisfying peroxidase activity is possibly due to the unimpeded access of H2O2 to the catalyst's active sites. The porous morphology provides the easy channeling of reactants and products. The periodic structure of the material also gave rise to acceptable reproducibility. Without material functionalization, the Ti/TiO2 NTs-GQDs can be a promising substitute for peroxidases for H2O2 detection.

Tailor-made molecular imprints for biological event intervention

Molecular imprints, which are crosslinked architectures containing specific molecular recognition cavities for targeting compounds, have recently transitioned from in vitro diagnosis to in vivo treatment. In current application scenarios, it has become an important topic to create new biomolecular recognition pathways through molecular imprinting, thereby inhibiting the pathogenesis and regulating the development of diseases. This review starts with a pathological analysis, mainly focusing on the corresponding artificial enzymes, enzyme inhibitors and antibody mimics with enhanced functions that are created by molecular imprinting strategies. Recent advances are highlighted in the use of molecular imprints as tailor-made nanomedicines for the prevention of three major diseases: metabolic syndrome, cancer, and bacterial/viral infections.

Nanotherapeutics for Alleviating Anesthesia-Associated Complications

Current management of anesthesia-associated complications falls short in terms of both efficacy and safety. Nanomaterials with versatile properties and unique nano-bio interactions hold substantial promise as therapeutics for addressing these complications. This review conducts a thorough examination of the existing nanotherapeutics and highlights the strategies for developing prospective nanomedicines to mitigate anesthetics-related toxicity. Initially, general, regional, and local anesthesia along with the commonly used anesthetics and related prevalent side effects are introduced. Furthermore, employing nanotechnology to prevent and alleviate the complications of anesthetics is systematically demonstrated from three aspects, that is, developing 1) safe nano-formulization for anesthetics; 2) nano-antidotes to sequester overdosed anesthetics and alter their pharmacokinetics; 3) nanomedicines with pharmacodynamic activities to treat anesthetics toxicity. Finally, the prospects and challenges facing the clinical translation of nanotherapeutics for anesthesia-related complications are discussed. This work provides a comprehensive roadmap for developing effective nanotherapeutics to prevent and mitigate anesthesia-associated toxicity, which can potentially revolutionize the management of anesthesia complications.

Hydrophilic molecularly imprinted resin-hexagonal boron nitride composite as a new adsorbent for selective extraction and determination of a carcinoid tumor biomarker in urine

BACKGROUND

The detection of disease biomarkers in biological samples plays an important role in early diagnosis and treatment of carcinoid tumor. However, due to the complexity of biological samples and the extremely low concentration of disease biomarkers, sample pretreatment is still the bottleneck of achieving accurate quantitative determination. In this work, new hydrophilic molecularly imprinted resin-hexagonal boron nitride (HMIR-h-BN) composites were developed and used as a new solid phase extraction (SPE) adsorbent for selective detection of 5-hydroxyindoleacetic acid (5-HIAA), a biomarker of carcinoid tumor, in urine.

RESULTS

Twenty-two types of HMIR-h-BN were successfully synthesized through growing hydrophilic molecularly imprinted resin on surface of activated two-dimensional h-BN nanosheets, and preparation parameters affecting the adsorption performance of HMIR-h-BN were investigated and optimized through adsorption experiments. HMIR-h-BN #19 (the ratio of resorcinol to hexamethylenetetramine: 6:3; the dosage of h-BN: 300 mg; the dosage of dummy template: 0.12 mmol; the imprinting time: 4 h) has demonstrated to be the optimal material for efficient separation and extraction of 5-HIAA. Combined with HPLC-UV, the limit of detection and the limit of quantification of 5-HIAA in real urine samples were 9.4 ng mL-1 and 31.3 ng mL-1, respectively, the coefficient of determination (R2) was 0.9996 in the linear range of 0.1-300 μg mL-1 and the relative recoveries ranged from 86.9 % to 97.7 % with RSD ≤5.1 %. Moreover, after being processed by HMIR-h-BN-SPE, there are no interferences from other peaks at the peak position of 5-HIAA.

SIGNIFICANCE

The HMIR-h-BN composite has been demonstrated to be capable of selective extraction of 5-HIAA from urine samples and have a significant purification effect. Based on the established HMIR-h-BN-SPE-HPLC-UV method, accurate quantitative determination of 5-HIAA in urine samples was achieved, which is expected to be applied in the early diagnostic of carcinoid tumor.

Enzyme-free ratiometric fluorescence and colorimetric dual-signal determination of glyphosate based on copper nanoclusters (ZIF/CuNCs) combined with blue carbon dots (bCDs)

A novel ratio fluorescent and colorimetric dual-signal sensing platform for detecting glyphosate based on blue carbon dots (bCDs) combined with ZIF/CuNCs nanomaterials that encapsulate copper nanoclusters (CuNCs) in a metal-organic framework (MOF). In principle, the immobilization of Cu2+ in ZIF/CuNCs results in complexation with imidazole in ZIF, leading to fluorescence quenching of ZIF/CuNCs, while the reference fluorophore bCDs remains unaffected. In addition, the colorimetric sensing strategy was based on the efficient peroxidase-like activity of bCDs binding to Cu2+, catalyzing H2O2 to generate OH. Under this condition, TMB could be oxidized to form blue oxTMB. However, when glyphosate was involved in the system, the fluorescence of ZIF/CuNCs was restored upon due to the strong chelation between Cu2+ and glyphosate, while the peroxidase-like activity of bCDs/Cu2+ decreased and resulted in the generation of fewer oxTMB, accompanied by a lighter blue color. The sensing platform was successfully applied to the determination of glyphosate in real samples of lake water and cabbage, demonstrating reliable and sensitive performance in practical applications.

A smartphone sensing platform for the sensitive and selective detection of clothianidin based on MIP-functionalized lanthanide MOF

A novel molecularly imprinted nanomaterial (Eu (BTC)-MPS@MIP) was synthesized on the surface of silanized europium-based metal-organic frameworks (Eu (BTC)-MPS) using 1, 3, 5-benzotrioic acid (H3BTC) as a ligand. The resulting Eu (BTC)-MPS@MIP was applied to constructing a smartphone sensing platform for the sensitive and selective detection of clothianidin (CLT) in vegetables. The synthesized Eu (BTC)-MPS@MIP demonstrated the successful formation of a typical core-shell structure featuring a shell thickness of approximately 70 - 80 nm. The developed sensing platform based on Eu (BTC)-MPS@MIP exhibited sensitivity in CLT detection with a detection limit of 4 µg/L and a linear response in the range 0.01 - 10 mg/L at excitation and emission wavelengths of 365 nm and 617 nm, respectively. The fluorescence sensing platform displayed excellent specificity for CLT detection, as evidenced by a high imprinting factor of 3.1. This specificity is primarily attributed to the recognition sites in the molecularly imprinted polymer (MIP) layer. When applied to spiked vegetable samples, the recovery of CLT ranged from 78.9 to 102.0%, with relative standard deviation (RSD) values falling between 2.2 and 6.2%. The quenching mechanism of Eu (BTC)-MPS@MIP toward CLT can be attributed to the inner filter effect (IFE), resulting from the optimal spectral overlap between the absorption spectrum of CLT and the excitation spectra of Eu (BTC)-MPS@MIP. The proposed method has the potential for extension to the detection of other pesticides by replacing the MIP recognition probes.

Disease diagnosis and application analysis of molecularly imprinted polymers (MIPs) in saliva detection

Saliva has significantly evolved as a diagnostic fluid in recent years, giving a non-invasive alternative to blood analysis. A high protein concentration in saliva is delivered directly from the bloodstream, making it a "human mirror" that reflects the body's physiological state. It plays an essential role in detecting diseases in biomedical and fitness monitoring. Molecularly imprinted polymers (MIPs) are biomimetic materials with custom-designed synthetic recognition sites that imitate biological counterparts renowned for sensitive analyte detection. This paper reviews the progress made in research about MIP biosensors for detecting saliva biomarkers. Specifically, we investigate the link between saliva biomarkers and various diseases, providing detailed insights into the corresponding biosensors. Furthermore, we discuss the principles of molecular imprinting for disease diagnostics and application analysis, including recent advances in integrated MIP-sensor technologies for high-affinity analyte detection in saliva. Notably, these biosensors exhibit high discrimination, allowing for the detection of saliva biomarkers linked explicitly to chronic stress disorders, diabetes, cancer, bacterial or viral-induced illnesses, and exposure to illicit toxic substances or tobacco smoke. Our findings indicate that MIP-based biosensors match and perhaps surpass their counterparts featuring integrated natural antibodies in terms of stability, signal-to-noise ratios, and detection limits. Additionally, we highlight the design of MIP coatings, strategies for synthesizing polymers, and the integration of advanced biodevices. These tailored biodevices, designed to assess various salivary biomarkers, are emerging as promising screening or diagnostic tools for real-time monitoring and self-health management, improving quality of life.

Designing a green poly(β-amino ester) for the delivery of nicotinamide drugs with biological activities and conducting a DFT investigation

The environmentally friendly polymerization process was carried out using microwave irradiation without additional solvents or catalysts to produce poly(β-amino ester) (PβAE) which served as a drug delivery system. PβAE was synthesized through Michael addition polymerization of 1,4-butane diol diacrylate and piperazine. Swelling and biodegradation studies were conducted in various solvents and phosphate-buffered saline (PBS, pH 7.4) at 37 °C to evaluate the properties of the polymeric gel. The PβAE matrix demonstrated solubility enhancement for hydrophobic antimicrobial and antitumor-active nicotinamide derivatives (TEINH, APTAT, and MOAPM), controlling their release over 10 days in (PBS). The successful formation of free and loaded PβAE with nicotinamide active materials was confirmed by spectroscopic analysis including Fourier-transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). Optimization and physical descriptor determination via the DFT/B3LYP-631(G) basis set were performed to aid in the biological evaluation of these compounds with elucidation of their physical and chemical interaction between poly(β-amino ester) and nicotinamide drugs.

Nanopore surface engineering of molecular imprinted mesoporous organosilica for rapid and selective detection of L-thyroxine

To develop a biosensing platform for precise diagnosis and management of thyroid-related diseases, the sensitive and selective recognition and identification of L-thyroxine (T4), a thyroid hormone, remains challenging. We herein introduce T4-imprinted mesoporous organosilica (T4-IMO) for sensitive and specific detection of T4 via the sophisticated engineering of pore surfaces using additives with different polarities. The pore surface of T4-IMO emitting a stable fluorescence signal is simply modified by fixed additives. Additives embedded in the pore surface promote the rebinding response of T4 into the recognized cavities, subsequently sensitizing T4 detection. Notably, T4-IMO containing abundant fluorine elements on the pore surface shows a high affinity toward T4, remarkably boosting the rebinding capacity. In addition to good selectivity to T4, the "turn-off" fluorescent signal exhibits a linear relationship with the logarithm of T4 concentration in a range of 0-500 nM with a detection limit of 0.47 nM in synthetic urine samples. Our findings can establish an insightful strategy for the rational design of molecular-recognition-based sensor systems for the selective and sensitive detection of target analytes.

Emerging trends in sensors based on molecular imprinting technology: Harnessing smartphones for portable detection and recognition

Molecular imprinting technology (MIT) has become a promising recognition technology in various fields due to its specificity, high efficiency, stability and eco-friendliness in the recognition of target. Molecularly imprinted polymers (MIPs), known as 'artificial receptors', are shown similar properties to natural receptors as a biomimetic material. The selectivity of recognition for targets can be greatly improved when MIPs are introduced into sensors, as known that MIPs, are suitable for the pretreatment and analysis of trace substances in complex matrix samples. At present, various sensors has been developed by the combination with MIPs for detecting and identifying trace compounds, biological macromolecules or other substances, such as optical, electrochemical and piezoelectric sensors. Smart phones, with their built-in sensors and powerful digital imaging capabilities, provide a unique platform for the needs of portability and instant detection. MIP sensors based on smart phones are expected to become a new research direction in the future. This review discusses the latest applications of MIP sensors in the field of detection and recognition in recent years, summarizes the frontier progress of MIP sensor research based on smart phones in the past two years, and points out the challenges, limitations and future development prospects.

A free carboxyl-decorated metal-organic framework with 3D helical chirality for highly enantioselective recognition

With the judicious selection of a designed polycarboxylate derived from L-phenylalanine, (S)-5-(((1-carboxy-2-phenylethyl)amino)methyl)isophthalic acid (H3L), a novel homochiral metal-organic framework decorated with a free carboxyl, {[Cu2(HL)2(bipy)]∙2H2O}n (Cu-MOF), has been designed and synthesized in a solvothermal process. The result of single crystal X-ray diffraction analysis showed that Cu-MOF had the character of a three-dimensional structure with helical chirality. As we expected, in Cu-MOF, one accessible free carboxylic acid group on H3L pointed toward the spiral channels, and the other two -COOH groups were utilized in bonding. The enantioseparation performance of Cu-MOF was thoroughly investigated and the results showed that Cu-MOF can specifically recognize S-1-(1-naphthyl) ethanol (S-NE) with enantiomeric excess (ee) value of 99.35 %, which was much higher than the other three racemates. The appropriate size together with suitable interaction sites played an important role in enantioseparations. Inspired by the excellent chiral recognition effects towards S-NE, the chiral recognition mechanism was experimentally clarified. A fully agreement observed in 13C CP MAS NMR analysis as well as the X-ray photoelectron spectroscopy (XPS) determination revealed that a strong hydrogen bonding interaction forces existed between the hydroxyl of the optical S-NE and the decorated -COOH in the chiral framework. The control experiment further identified the decisive role of the uncoordinated carboxyl group in Cu-MOF. In addition, the strong intermolecular off-set π-π interactions between the phenyl ring involved with the coordinated COO- groups in Cu-MOF and the naphthyl ring of S-NE, was the another important factor for the specifical enantioseparation of S-enantiomer. On the basis of strong intermolecular hydrogen bonding, NE racemates were enantioselective discriminated and enantiomeric purity can be determined by means of Raman scattering spectroscopy.

Conductive imprinted polymeric interfacially modified electrochemical sensors based on covalently bonded layer-by-layer assembly of Gr/Au with flower-like morphology for sensitive detection of 2,4,6-TCP

Polymeric membrane sensors based on molecular imprinted polymers (MIPs) have been attractive analytical tools for detecting organic species. However, the MIPs in electrochemical sensors developed so far are usually prepared by in situ polymerization of pre-polymers and non-covalent adsorption on the surface of the working electrode. Meanwhile, the MIPs in the electrochemical sensors developed are typically made of a non-conductive polymer film. This results in a relatively low current due to the lack of electron transfer. Additionally, the smoothness of the traditional electrochemical substrate results in a low specific surface area, which reduces the sensitivity of the electrochemical sensor. Here, we describe a novel electrochemical sensor with a conductive interface and MIPs modification. The electrochemical sensor was modified by covalent coupled layer by layer self-assembly with the imprinted polymer film. The incorporation of these two conductive functional materials improves the conductivity of the electrodes and provides interface support materials to obtain high specific surface area. By using 2,4,6-trichlorophenol as the model, the sensitivity of the developed conductive sensor was greatly improved compared to that of the traditional MIPs sensor. We believe that the proposed MIPs-based sensing strategy provides a general and convenient method for making sensitive and selective electrochemical sensors.

A new SERS quantitative analysis method for trace malathion with recognition and catalytic amplification difunctional MOFTb@Au@MIP nanoprobe

New multifunctional nanomaterial preparation and its application to trace pollutant analysis are interesting to peoples. Using terbium metal-organic framework loaded gold nanoparticles (MOFTb@Au) as the nanosubstrate and 3-aminopropyltriethoxysilane (APTES) as the functional monomer, a new bifunctional nanosurface molecularly imprinted polymer nanoprobe of MOFTb@Au@MIP with strongly recognition and catalytic amplification functions was prepared by the microwave sol-gel procedure. It was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier infrared spectroscopy (FTIR) and other techniques. The nanoprobe was found to specifically recognize malathion (MAL) and catalyze the L-cysteine (Cys)-HAuCl4 nanogold indicator reaction to amplify the molecular spectral signal. The gold nanoparticles (AuNPs) generated in the system show a strong surface-enhanced Raman scattering (SERS) effect, resonant Rayleigh scattering (RRS) peak and UV absorption (Abs) peak at 1615 cm-1, 370 nm and 520 nm, respectively. Based on this, a new SERS/RRS/Abs trimode method for the detection of MAL can be established. It has been applied to the analysis of cereal samples with satisfactory recoveries of 95.2-107.4% and precision of 3.76-9.06%.

Enhancing Cytochrome C Recognition and Adsorption through Epitope-Imprinted Mesoporous Silica with a Tailored Pore Size

We have reported the synthesis of epitope-imprinted mesoporous silica (EIMS) with an average pore size of 6.2 nm, which is similar to the geometrical size of the target protein, cytochrome C (Cyt c, 2.6 × 3.2 × 3.3 nm3), showing great recognition and large-scale adsorption performance. The characteristic fragment of Cyt c was used as a template and docked onto the surface of C16MIMCl micelles via multiple interactions. Nitrogen adsorption-desorption and transmission electron microscopy confirmed the successful preparation of EIMS. Due to the ordered pore structure, larger pore size, and high specific surface area, the prepared EIMS show superior specificity (IF = 3.8), excellent selectivity toward Cyt c, high adsorption capacity (249.6 mg g-1), and fast adsorption equilibrium (10 min). This study demonstrates the potential application of EIMS with a controllable pore size for high-effective and large-scale separation of Cyt c, providing a new approach for effective biomacromolecular recognition.

Hollow CoZnSe@CN nanocage with enzymatic activity for determination of tetracycline using smartphone platforms and virtual reality revealing

Antibiotic residues in the environment pose a serious threat to ecosystems and human health. Therefore, it is important to develop sensitive and rapid in situ detection methods. In this work, the designed nanozymes, with excellent four enzyme activities, were proved to be constituted of unique hollow nanocage structures (CoZnSe@CN HCs). Based on the peroxidase-like enzymes, a portable colorimetric sensor was constructed for the on-site determination of tetracycline (TC) in real samples. The linear range of TC detection was 0.1-100 μM, and the detection limit was 0.02 μM. At the same time, colorimetric detection and smartphones have also been combined for on-site colorimetric detection of TC. In-depth exploration of the detection mechanism showed that TC could be bound with the material, inhibiting the production of oxidized 3,3',5,5'-tetramethylbenzidine. The sensor was also used for the detection of TC in environmental soil and water samples. This study can provide an intelligent detection method for environmental monitoring.

Paper-based analytical device for sensitive colorimetric determination of sulfonamides in pharmaceutical samples

Sulfa drugs are frequently used to treat infections, particularly in antibiotic resistant people. There are several techniques available to determine sulfa drugs, however, they are laborious operation, reagent consumption, expensive, and need specialized types of equipment. Here, a new, very simple and inexpensive paper-based analytical device described for the determination of five sulfa drugs: sulfacetamide, sulfadiazine, sulfamerazine, sulfamethoxazole, and sulfathiazole in pharmaceutical preparations. The method is a one-step reaction, based on the colorimetric reaction between acid-hydrolyzed sulfa drugs and 4-dimethylaminobenzaldehyde. Using a smartphone, the RGB value of color intensity was used as an analytical signal. The paper-based device displayed linear ranges of 0.10-5.00 µg mL-1, linear correlations ranging from 0.9903 to 0.9972, limits of detection 0.0030 to 0.0082 µg mL-1, and RSD of ≤0.258 under optimal conditions. The suggested approach was applied for determining five sulfa drugs in pharmaceutical formulations. This approach is appropriate for pharmaceutical applications since it is inexpensive, simple to utilize, sensitive, and selective.

A symmetric bis(salamo)-like fluorescent chemosensor for identifying HCO3- and CO32- and its application

In this work, we successfully designed and synthesized a methoxydisubstituted bis(salamo)-type fluorescent chemical sensor BS, which can be applied as a highly sensitive and selective fluorescence probe for HCO3- and CO32- detection. The LODs of HCO3- and CO32- were experimentally calculated to be 5.4068 × 10-8 M and 4.4517 × 10-8 M, respectively. After relevant experiments, the sensing mechanism was investigated. Moreover, the application of the sensor in practice is explored, and the sensor BS can be loaded on portable test strips for ion detection. In the field of ion detection, salamo-like chemical sensors have been less studied compared to other sensor molecules, especially for the recognition and detection of anions. Therefore, this study will to some extent contribute to expanding the application of salamo-like compounds.

A ratiometric fluorescence sensor based on the inner filtration effect of gold nanoparticles on quantum dots for monitoring dopamine

In this study, a smart phone assisted ratiometric fluorescence sensor was designed for detecting dopamine (DA). The ratiometric fluorescence sensor was prepared by simple physical mixing green quantum dots (GQDS) and red quantum dots (RQDS). DA could induce gold nanoparticles (AuNPs) aggregate via hydrogen-bonding interactions, and further changed the absorption spectrum of gold nanoparticles to overlap with a certain emission spectrum of ratiometric fluorescence sensor. AuNPs had inner filtration effect (IFE) on the ratiometric fluorescence sensor. Due to the IFE, the dispersive AuNPs could quench GQDS, whereas the clustered AuNPs could quench RQDS. With the addition of DA, the color of ratiometric fluorescence changed from orange red to green. To simplify the detection process, a smartphone was employed to detecting DA in human urine by measuring RGB value of fluorescence color changes with a detection limit of 86 nM. This proposed method has the advantages of low cost, easy prevalence and simple operation, thus provides a great promise for rapid detection of biomarker in biological samples.

Imprinted Polymers on the Route to Plastibodies for Biomacromolecules (MIPs), Viruses (VIPs), and Cells (CIPs)

Around 30% of the scientific papers published on imprinted polymers describe the recognition of proteins, nucleic acids, viruses, and cells. The straightforward synthesis from only one up to six functional monomers and the simple integration into a sensor are significant advantages as compared with enzymes or antibodies. Furthermore, they can be synthesized against toxic substances and structures of low immunogenicity and allow multi-analyte measurements via multi-template synthesis. The affinity is sufficiently high for protein biomarkers, DNA, viruses, and cells. However, the cross-reactivity of highly abundant proteins is still a challenge.

Developments in food neonicotinoids detection: novel recognition strategies, advanced chemical sensing techniques, and recent applications

Neonicotinoid insecticides (NEOs) are a new class of neurotoxic pesticides primarily used for pest control on fruits and vegetables, cereals, and other crops after organophosphorus pesticides (OPPs), carbamate pesticides (CBPs), and pyrethroid pesticides. However, chronic abuse and illegal use have led to the contamination of food and water sources as well as damage to ecological and environmental systems. Long-term exposure to NEOs may pose potential risks to animals (especially bees) and even human health. Consequently, it is necessary to develop effective, robust, and rapid methods for NEOs detection. Specific recognition-based chemical sensing has been regarded as one of the most promising detection tools for NEOs due to their excellent selectivity, sensitivity, and robust interference resistance. In this review, we introduce the novel recognition strategies-enabled chemical sensing in food neonicotinoids detection in the past years (2017-2023). The properties and advantages of molecular imprinting recognition (MIR), host-guest recognition (HGR), electron-catalyzed recognition (ECR), immune recognition (IR), aptamer recognition (AR), and enzyme inhibition recognition (EIR) in the development of NEOs sensing platforms are discussed in detail. Recent applications of chemical sensing platforms in various food products, including fruits and vegetables, cereals, teas, honey, aquatic products, and others are highlighted. In addition, the future trends of applying chemical sensing with specific recognition strategies for NEOs analysis are discussed.

Serotonin: A new super effective functional monomer for molecular imprinting. The case of TNF-α detection in real matrix by Surface Plasmon Resonance

Molecular imprinting and related technologies are becoming increasingly appreciated in bioanalysis and diagnostic applications. Among the imprinted polymers, we have already demonstrated that the endogenous neurotransmitters (NTs) dopamine (DA) and norepinephrine (NE) can be efficiently used as natural and sustainable monomers to straightforwardly design and synthesize a new generation of green and "soft" Molecularly Imprinted BioPolymers (MIBPs). Here, we demonstrated for the first time the ability of a further NT, i.e., serotonin (SE), in forming adhesive imprinted nanofilms coupled to label-free optical biosensing. Its imprinting efficiency is compared with those obtained with PDA and PNE. As a model study, tumor necrosis factor-alpha (TNF-α) was selected as a biomolecular target of interest in clinical diagnostics. The biomimetic receptor was coupled to Surface Plasmon Resonance (SPR), and TNF-α detection was performed in label-free and real-time manner both in buffer and biological matrices, i.e. synovial fluid and human serum. The results indicate that, under the same imprinting and binding conditions, the analytical performances of PSE are impressively superior to those of PDA and PNE. The PSE-based MIBP was able to detect TNF-α in human matrices with a good sensitivity, selectivity, and repeatability.

Assessing the greenification potential of cyclodextrin-based molecularly imprinted polymers for pesticides detection

Cyclodextrins, with their unparalleled attributes of eco-friendliness, natural abundance, versatile utility, and facile functionalization, make a paramount contribution to the field of molecular imprinting. Leveraging the unique properties of cyclodextrins in molecularly imprinted polymers synthesis has revolutionized the performance of molecularly imprinted polymers, resulting in enhanced adsorption selectivity, capacity, and rapid extraction of pesticides, while also circumventing conventional limitations. As the concern for food quality and safety continues to grow, the need for standard analytical methods to detect pesticides in food and environmental samples has become paramount. Cyclodextrins, being non-toxic and biodegradable, present an attractive option for greener reagents in imprinting polymers that can also ensure environmental safety post-application. This review provides a comprehensive summary of the significance of cyclodextrins in molecular imprinting for pesticide detection in food and environmental samples. The recent advancements in the synthesis and application of molecularly imprinted polymers using cyclodextrins have been critically analyzed. Furthermore, the current limitations have been meticulously examined, and potential opportunities for greenification with cyclodextrin applications in this field have been discussed. By harnessing the advantages of cyclodextrins in molecular imprinting, it is possible to develop highly selective and efficient methods for detecting pesticides in food and environmental samples while also addressing the challenges of sustainability and environmental impact.

Preparation of lysozyme-imprinted mesoporous Zr-based metal-organic frameworks with remarkable specific recognition

The development of high-performance protein-imprinted materials remains challenging due to defects concerning high mass transfer resistance and non-specific binding, which are crucial for protein purification and enrichment. In this paper, lysozyme-imprinted mesoporous Zr-based MOF (mesoUiO-66-NH2@MIPs) with specific and selective recognition of lysozyme (Lyz) were prepared by surface imprinting technology. In particular, the excellent hydrophilicity mesoporous MOFs (mesoUiO-66-NH2) with a pore size of 10 nm was prepared as a carrier for Lyz immobilization by an auxiliary modulation strategy to regulate the microporous structure of UiO-66-NH2 with the propionic acid solution, enabling massive loading of the macromolecular protein Lyz. The mesoUiO-66-NH2@MIPs reached a maximum saturation adsorption of 206.54 mg g-1 on Lyz in 20 min at 25 °C with an imprinting factor of 2.57 and selection factors of 2.02, 2.34, and 2.45 for cytochrome c (Cyt c), bovine serum albumin (BSA) and bovine hemoglobin (BHb), respectively. More importantly, the mesoUiO-66-NH2@MIPs could specifically recognize Lyz from the mixed protein system. The adsorption capacity of Lyz could still reach 78.55% after 5 cycles with good cyclic regeneration performance. This provides a new research option for developing and applying novel porous MOF in biomolecule imprinting technology and the specific separation of biomolecules.

Synthesis of molecularly imprinted polymer by precipitation polymerization for the removal of ametryn

Ametryn (AME) is a triazine herbicide which is mainly used to kill unwanted herbs in crops. Despite its importance in agriculture, the usage of AME also poses a risk to humans and the ecosystem due to its toxicity. Hence, it is important to develop a method for the effective removal of AME from various water sources which is in the form of molecular imprinting polymer (MIP). In this study, MIP of AME was synthesized via precipitation polymerization using AME as the template molecule with three different functional monomers including methacrylic acid (MAA), acrylamide (AAm) and 2-vinylpyridine (2VP). The three different synthesized polymers namely MIP (MAA), MIP (AAm) and MIP (2VP) were characterized using Fourier Infra-red spectroscopy (FTIR) and Field Emission Electron Microscopy (FESEM). Then, the batch binding study was carried out using all three MIPs in which MIP (MAA) attained the highest rebinding efficiency (93.73%) among the synthesized polymers. The Energy-Dispersive X-ray spectroscopy (EDX) analysis, Brunauer-Emmett-Teller (BET) analysis and thermogravimetric analysis (TGA) were also conducted on the selected MIP (MAA). Adsorption studies including initial concentration, pH and polymer dosage were also conducted on MIP (MAA). In this study, the highest adsorption efficiency was attained at the optimum condition of 6 ppm of AME solution at pH 7 with 0.1 g of MIP (MAA). MIP (MAA) was successfully applied to remove AME from spiked distilled water, tap water and river water samples with removal efficiencies of 95.01%, 90.24% and 88.37%, respectively.