Fundamentals, Synthetic Strategies and Applications of Non-Covalently Imprinted Polymers.

Molecular imprinting has emerged as an important and practical technology to create economical and stable synthetic mimics of antibodies and enzymes. It has already found a variety of important applications, such as affinity separation, chemical/biological sensing, disease diagnostics, proteomics, bioimaging, controlled drug release, and catalysis. In the past decade, significant breakthroughs have been made in non-covalently imprinted polymers, from their synthesis through to their applications. In terms of synthesis, quite a few versatile and facile imprinting approaches for preparing MIPs have been invented, which have effectively solved some key issues in molecular imprinting. Additionally, important applications in several areas, such as sensors, proteomics and bioimaging, have been well demonstrated. In this review, we critically and comprehensively survey key recent advances made in the preparation of non-covalently imprinted polymers and their important applications. We focus on the state-of-art of this technology from three different perspectives: fundamentals, synthetic strategies, and applications. We first provide a fundamental basis for molecular imprinting technologies that have been developed, which is extremely helpful for establishing a sound understanding of the challenges in molecular imprinting. Then, we discuss in particular the major breakthroughs within the last ten years (2014-2024), with emphasis on new imprinting approaches, what strengths the breakthroughs can provide, and which new applications the properties of the prepared non-covalently imprinted polymers are fit for.

Sustainable and effective reconditioning of SPR gold chips functionalized with molecularly imprinted polynorepinephrine.

Surface Plasmon Resonance (SPR) technology has revolutionized the study of affinity-based biomolecular interactions, offering label-free and real-time analysis capabilities. However, traditional SPR gold chips have been viewed as disposable due to challenges in post-use reconditioning, leading to significant resource wastage and increased costs. To address this issue, we propose a novel approach utilizing polynorepinephrine-based (PNE) Molecularly Imprinted Bio-Polymers (MIBPs) as alternative receptors to conventional antibodies. Self-adhesive MIBPs do not require covalent immobilization. This enables efficient and rapid chip functionalization and post-use removal, facilitating multiple reuses of the plasmon source without compromising analytical performance. We conducted a thorough characterization and data analysis, confirming the robustness and repeatability of a single MIBP-functionalized chip for human IgG detection. 10 cycles of reconditioning and reuse, assayed by 60 kinetic calibrations, were performed. Our findings demonstrate the potential indefinite reuse of SPR chips facilitated by PNE MIBPs, with implications for streamlining test development and routine implementation in SPR biosensing applications. Therefore, they represent a sustainable solution to the longstanding challenge of disposable SPR gold chips also by reducing the reliance on animal-derived Abs for bioanalytic testing. Being also extremely low-cost and green, PNE-based MIBPs minimize the ecological footprint associated with traditional SPR assays. Overall, our work represents a significant advancement towards the development of reusable SPR biosensors. It promises a more sustainable and cost-effective future for biomedical research and diagnostic applications, with application on other transducers and bioanalytical platforms.

A novel green molecularly imprinted polymers synthesized in an aqueous medium as S-metolachlor sensitive materials.

A new molecularly imprinted polymer (MIP) sensitive and selective for S-metolachlor herbicide was synthesized by bulk polymerization with the use of N-isopropylacrylamide, acrylamide, and acrylic acid as functional monomers, and N,N'- methylenebis(acrylamide) as a cross-linker. A novel method for obtaining MIP toward S-metolachlor in an aqueous medium and at room temperature, according to the principles of green chemistry, has been discovered, in comparison to synthesis methods at high temperatures and using organic solvents. Under selected experimental conditions, the batch mode type of sorption was carried out efficiently, with S-metolachlor absorption of 2.4 mg per 1 g of MIP and 0.5 mg per 1 g of NIP. The selectivity of the sorbent towards other herbicides and pesticides was also tested, obtaining an ability to recognize S-metolachlor molecules 3.2 times better than atrazine, 6 times better than glyphosate, and 6.2 times better than fenoxaprop-P-ethyl. The FT-IR and SEM analyses were performed to characterize the structure of the synthesized polymers.

Molecularly Imprinted Polymers for Highly Specific Bioorthogonal Catalysis inside Cells.

Transition metal catalysts (TMCs) mediated bioorthogonal catalysis expand the chemical possibilities within cells. Developing synthetic TMCs tools that emulate the efficiency and specificity of natural metalloenzymes is a rewarding yet challenging endeavor. Here, we highlight the potential of molecularly imprinted enzyme mimics (MIEs) containing a Cu center and specific substrate binding domain, for conducing dimethylpropargyloxycarbonyl (DmProc) cleavage reactions within cells. Our studies reveal that the Cu-MIEs act as highly specific guides, precisely catalyzing target substrates, even in glutathione (GSH)-rich cellular environments. By adapting templates similar to the target substrates, we evolved Cu-MIEs activity to a high level and provided a method to broaden its scope to other unique substrates. This system was applied to a thyroid hormone (T3)-responsive gene switch model, inducing firefly luciferase expression by T3 in cells. This approach verifies that MIEs effectively rescue DmProc-bearing T3 prodrugs and seamlessly integrating themself into cellular biocatalytic networks.

Advances in the selection of functional monomers for molecularly imprinted polymers: A review.

Molecularly imprinted polymers, a type of special polymer materials, are widely used in biosensing and other fields due to their ability to specifically recognize target molecules, often called "artificial receptors.". Nowadays, researchers are constantly exploring new design and synthesis methods for molecularly imprinted materials to improve the selectivity and sensitivity of molecularly imprinted materials. Among them, the selection of functional monomers has attracted great attention. This review comprehensively analyzes and discusses the selection methods of functional monomers. The most commonly used functional monomers among different types of templates are screened based on the structural properties of the template molecules, including the selection of functional monomers among ion-imprinted polymers, protein-imprinted polymers, and bacterial imprinted polymers. The rich binding sites and functional group types of multifunctional monomers are also highlighted to advance the development of molecular imprinting technology. The article further explores the current challenges and prospects in the selection of functional monomers and emphasizes multiplex experiments and computer simulations as important directions for future research. This review provides comprehensive information and constructive guidelines for researchers in selecting functional monomers in areas such as analytical chemistry and biosensors.

Distribution of xylan linked glucuronic acid labelled by molecularly imprinted polymers on pulp fiber surface.

Efficiently utilization of plant resources is heavily restricted by the resistance of lignocellulose in plant cells, which is related to the interlinkages of lignocellulose components. Hemicellulose in plant cell wall is bound to cellulose by hydrogen bond and linked with lignin in lignin-carbohydrate complex (LCC). In the xylan chain of hemicellulose, glucuronic acid (GA) is a typical side-group, which provides clues for us to label and locate hemicellulose. The way to label GA on the surface of pulp fibers obtained from pulping process is benefit to explore the deconstruction of lignocellulose. Herein, a new visualization method, fluorescence modified molecularly imprinted polymers (MIP) were applied to recognize and locate GA on the pulp fiber surface. The method combining fluorescence imaging and integrated 3D fiber structure verified the feasibility of the MIP for specific GA recognition. The results showed that xylan (represented by GA) was closely attached to lignin, distributed along the inner wall of pulp fiber cells, and gradually taken off from the inside edge of fiber cells with the deconstruction of lignocellulose. This research provided a basis to develop visualization bioimaging technology to identify biomass components.

A sensitive enzyme-free electrochemical sensor based on ZnWO4@co-MNPC@MIP for specific recognition and determination of chloramphenicol in milk sample.

We have carefully built a new chloramphenicol (CAP) electrochemical sensor, which takes the zinc tungstate @ cobalt magnetic nanoporous carbon @ molecularly imprinted polymer (ZnWO4@Co-MNPC@MIP) as the core. First, we successfully prepared Co-MNPC nanomaterials using an efficient one-step hydrothermal method and a direct carbonization method. Next, we recombined ZnWO4 with Co-MNPC and synthesized the completely new ZnWO4@Co-MNPC complex by using the hydrothermal method. To further improve its performance, we combined ZnWO4@Co-MNPC with a molecular imprinted polymer and coated a molecular imprinted (MIP) shell on the surface of ZnWO4@Co-MNPC by precipitation polymerization. This shell not only gives the sensor a new performance but also gives it a stronger peak current, resulting in a more accurate detection of CAP. Under optimal conditions, the ZnWO4@Co-MNPC@MIP (MMIP) electrode has a stronger CAP detection peak current than the one-component electrode, with a fairly wide linear range: 0.007-200 µM and 200-1400 µM. Even more surprisingly, the detection limit is as low as 0.0027 µM, which allows the sensor to maintain excellent selectivity and stability in the face of various interferences, making it an excellent electrochemically modified electrode. Compared to magnetic non-molecular imprint sensors (MNIPs), MMIP sensors have higher detection efficiency. After practical application, we found that the ZnWO4@Co-MNPC@MIP modified electrode was satisfactory in milk samples.

Magnetic multi-template molecularly imprinted polymers for selective simultaneous extraction of chlorophenols followed by determination using HPLC.

Magnetic multi-template molecularly imprinted polymers (M-mt-MIPs) were successfully synthesized by surface imprinting and multi-template imprinting strategy, using polydopamine coated magnetic multi-walled carbon nanotubes as supporting materials, five typical chlorophenols (CPs) as templates, methacrylic acid as functional monomer and ethylene glycol dimethacrylate as cross-linker. Compared to non-imprinted polymers (NIPs), the as-prepared M-mt-MIPs showed high adsorption capacity (32.58‒80.63 mg g-1), rapid mass transfer and specific selectivity for the five targeted CPs, which were applied as magnetic solid-phase extraction (MSPE) adsorbents. Parameters affecting MSPE efficiency were detailed investigated, such as adsorbents dosage, sample pH, extraction time, type and volume of desorption solvent and salt effect. Combined with HPLC-DAD, a simple, rapid and sensitive method was established, showing good linearity (2‒200 µg L-1), low limits of detection (0.32‒0.49 µg L-1), and high enrichment factors (35.2‒108). The developed M-mt-MIPs-MSPE-HPLC method was applied to enrich and determine CPs in tannery wastewater, wet-blue and crust leather, and satisfactory spiking recoveries were attained in the range of 73.95‒109.7% with relative standard deviations (RSDs) of 2.13-8.48%. This study provided a new alternative material and method to rapid simultaneously extract and analyze low concentration of typical CPs in complicated matrices.

Preparation of dual recognition adsorbents based on molecularly imprinted polymers and aptamer for highly sensitive recognition and enrichment of ochratoxin A.

In light of the significant risks that mycotoxins posed to public health and environmental safety, this research developed an adsorbent MIPs/Apt/AuNPs@ZIF-67 (MA-AZ) utilizing a dual-recognition approach combining molecularly imprinted polymers (MIPs) and aptamer (Apt). This innovative method enabled the effective and highly selective recognition and enrichment of ochratoxin A (OTA). ZIF-67 was utilized as a carrier with a substantial specific surface area, and gold nanoparticles (AuNPs) were loaded on its surface to fix the thiol-modified Apt on the surface of the carrier. Then, an initiator was used to initiate a polymerization reaction, and the generated MIPs coated Apt/AuNPs@ZIF-67, thereby synthesizing the MA-AZ with a "synergistic recognition" effect. The Apt significantly increased the number of recognition sites within the imprinted cavities, and MIPs played roles in identifying targets, fixing and protecting Apt. The combination of the both produced the effect of "1+1>2". The study on the adsorption performance of MA-AZ found that the adsorption capacity of MA-AZ could reach 65.1 mg/g, and the imprinted factor was 5.48. In addition, MA-AZ exhibited excellent stability, specificity, reusability and recovery rate. Thus, this study offers valuable insights for the recognition and enrichment of hazardous substances, and helps to promote the rapid development of safety detection.

Synergistic signal-amplification effect of silver nanowires and bifunctional monomers on molecularly imprinted electrochemical sensor for diuron analysis.

Molecularly imprinted polymers (MIP) have been widely owing to their specificity, however, their singular structure imposes limitations on their performance. Current enhancement methods, such as doping with inorganic nanomaterials or introducing various functional monomers, are limited and single, indicating that MIP performances require further advancement. In this work, a dual-modification approach that integrates both conductive inorganic nanomaterials and diverse bifunctional monomers was proposed to develop a multifunctional MIP-based electrochemical (MMIP-EC) sensor for diuron (DU) detection. The MMIP was synthesized through a one-step electrochemical copolymerization of silver nanowires (AgNWs), o-phenylenediamine (O-PD), and 3,4-ethylenedioxythiophene (EDOT). DU molecules could conduct fluent electron transfer within the MMIP layer through the interaction between anchored AgNWs and bifunctional monomers, and the abundant recognition sites and complementary cavity shapes ensured that the imprinted cavities exhibit high specificity. The current intensity amplified by the two modification strategies of MMIP (3.7 times) was significantly higher than the sum of their individual values (3.2 times), exerting a synergistic effect. Furthermore, the adsorption performance of the MMIP was characterized by examining the kinetics and isotherms of the adsorption process. Under optimal conditions, the MMIP-EC sensor exhibits a wide linear range (0.2 ng/mL to 10 µg/mL) for DU detection, with a low detection limit of 89 pg/mL and excellent selectivity (an imprinted factor of 10.4). In summary, the present study affords innovative perspectives for the fabrication of MIP-EC sensor with superior analytical performance.

An ultrasensitive paper-based SERS sensor for detection of nucleolin using silver-nanostars, plastic antibodies and natural antibodies.

A state-of-the-art, ultrasensitive, paper-based SERS sensor has been developed using silver nanostars (AgNSs) in combination with synthetic and natural antibodies. A key component of this innovative sensor is the plastic antibody, which was synthesized using molecularly imprinted polymer (MIP) technology. This ground-breaking combination of paper substrates/MIPs with AgNSs, which is similar to a sandwich immunoassay, is used for the first time with the aim of SERS detection and specifically targets nucleolin (NCL), a cancer biomarker. The sensor device was carefully fabricated by synthesizing a polyacrylamide-based MIP on cellulose paper (Whatman Grade 1 filter) by photopolymerization. The binding of NCL to the MIP was then confirmed by natural antibody binding using a sandwich assay for quantitative SERS analysis. To facilitate the detection of NCL, antibodies were pre-bound to AgNSs with a Raman tag so that the SERS signal could indicate the presence of NCL. The composition of the sensory layers/materials was meticulously optimized. The intensity of the Raman signal at ∼1078 cm-1 showed a linear trend that correlated with increasing concentrations of NCL, ranging from 0.1 to 1000 nmol L-1, with a limit of detection down to 0.068 nmol L-1 in human serum. The selectivity of the sensor was confirmed by testing its analytical response in the presence of cystatin C and lysozyme. The paper-based SERS detection system for NCL is characterized by its simplicity, sustainability, high sensitivity and stability and thus embodies essential properties for point-of-care applications. This approach is promising for expansion to other biomarkers in various fields, depending on the availability of synthetic and natural antibodies.

Recent progress of the research of metal-organic frameworks-molecularly imprinted polymers (MOFs-MIPs) in food safety detection field.

Food safety is an important cornerstone of protecting human health and life. Therefore, it is of great significance to detect possible pollutants in food sensitively and efficiently. Molecularly imprinted polymers (MIPs) and metal-organic frameworks (MOFs) have been widely used in the adsorption and detection of food pollutants. However, traditional MIPs have problems such as uneven loading of the imprinted cavity and slow mass transfer efficiency. While the adsorption of MOFs has low specificity and cannot accurately identify target molecules. Therefore, some researchers have taken advantage of the high specific recognition abilities of MIPs and the large specific surface areas, high porosity and easy functionalization of MOFs to combine MOFs with MIPs, and have achieved a series of important results in the field of food safety detection. This paper reviews the research progress of the application of MOFs-MIPs in the field of food safety detection from 2019 to 2024. It furnishes researchers interested in this domain with a rapid and comprehensive grasp of the latest research status, it also offers them a chance to anticipate future development trends, thereby supporting the continuous advances of MOFs-MIPs in food safety detection.

Preparation of cholesterol-imprinted polymer for selective adsorption of cholesterol from gastrointestinal mimicking solution.

The purpose of this study is to synthesize a highly selective adsorbent to remove cholesterol, one of the most important causes of cardiovascular diseases, from the intestinal mimic solution (IMS). For this purpose, cholesterol imprinted polymers were synthesized by suspension polymerization method using the molecular imprinting technique. In the first step, the functional monomer MATyr with hydrophobic character was synthesized. Then, the cholesterol-MATyr monomer precomplex was formed and the polymerization process was carried out by adding cross-linkers with the comonomer HEMA. The synthesized polymer poly(2-hydroxyethyl methacrylate-N-methacryloyl-(L)-tyrosine methylester) poly(HEMA-MATyr) was characterized by FTIR and SEM. The cholesterol adsorbing behavior of the synthesized poly(HEMA-MATyr) microbeads adsorbent was investigated at different initial concentrations, different temperatures, and adsorption times. The maximum adsorption capacity of microbeads was determined as 56.67 mg/g at a concentration of 2.5 mg/L. The amount of cholesterol adsorbed in the IMS was found as 83.07 mg/g polymer, which indicates that 92% of the cholesterol in the medium was adsorbed. The selectivity behavior of the cholesterol imprinted polymer was carried out with the stigmasterol and estradiol molecules, which are similar in structure, molecular weight, and character to the cholesterol molecule. The chol-imprinted polymeric beads were 21.38 and 10.08 fold more selective for cholesterol compared to estradiol and stigmasterol steroids used as competitor agents respectively. Kinetic and isotherm calculations of the synthesized cholesterol imprinted polymer were made and reusability experiments were carried out.

Effect of Various Carbon Electrodes on MIP-Based Sensing Proteins Using Poly(Scopoletin): A Case Study of Ferritin.

Sensitivity in the sub-nanomolar concentration region is required to determine important protein biomarkers, e.g., ferritin. As a prerequisite for high sensitivity, in this paper, the affinity of the functional monomer to the macromolecular target ferritin in solution was compared with the value for the respective molecularly imprinted polymer (MIP)-based electrodes, and the influence of various surface modifications of the electrode was investigated. The analytical performance of ferritin sensing was investigated using three different carbon electrodes (screen-printed carbon electrodes, single-walled-carbon-nanotube-modified screen-printed carbon electrodes, and glassy carbon electrodes) covered with a scopoletin-based MIP layer. Regardless of the electrode type, the template molecule ferritin was mixed with the functional monomer scopoletin, and electropolymerization was conducted using multistep amperometry. All stages of MIP preparation were followed by evaluating the diffusional permeability of the redox marker ferricyanide/ferrocyanide through the polymer layer by differential pulse voltammetry. The best results were obtained with glassy carbon electrodes. The MIP sensor responded up to 0.5 µM linearly with a Kd of 0.30 µM. Similar results were also obtained in solution upon the interaction of scopoletin and ferritin using fluorescence spectroscopy, resulting in the quenching of the scopoletin signal, with a calculated Kd of 0.81 µM. Moreover, the binding of 1 µM ferritin led to 49.6% suppression, whereas human serum albumin caused 8.6% suppression.

Facile biotic/abiotic sandwich detection system for the highly sensitive detection of human serum albumin and glycated albumin.

Quantifying glycated albumin (GA) levels in the blood is crucial for diagnosing diabetes because they strongly correlate with blood glucose concentration. In this study, a biotic/abiotic sandwich assay was developed for the facile, rapid, and susceptible detection of human serum albumin (HSA) and GA. The proposed sandwich detection system was assembled using a combination of two synthetic polymer receptors and natural antibodies. Molecularly imprinted polymer nanogels (MIP-NGs) for HSA (HSA-MIP-NGs) were used to mimic capture antibodies, whereas antibodies for HSA or GA were used as primary antibodies and fluorescent signaling MIP-NGs for the Fc domain of IgG (F-Fc-MIP-NGs) were used as a secondary antibody mimic to indicate the binding events. The HSA/anti-HSA/F-Fc-MIP-NGs complex, formed by incubating HSA and anti-HSA antibodies with F-Fc-MIP-NGs, was captured by HSA-MIP-NGs immobilized on the chips for fluorescence measurements. The analysis time was less than 30 min, and the limit of detection was 15 pM. After changing the anti-HSA to anti-GA (monoclonal antibody), the fluorescence response toward GA exceeded that of HSA, indicating successful GA detection using the proposed sandwich detection system. Therefore, the proposed system could change the detection property by changing a primary antibody, indicating that this system can be applied to various target proteins and, especially, be a powerful approach for facile and rapid analysis methods for proteins with structural similarity.

Molecularly imprinted polymers in the analysis of chlorogenic acid: A review.

Chlorogenic acid, a phenolic compound, is prevalent across various plant species and has been known for its pharmacological advantages. Health care experts have identified chlorogenic acid as a potential biomarker for treatment of a wide range of illnesses. Therefore, achieving efficient extraction and analysis of chlorogenic acid from plants and their products has become essential. Molecularly imprinted polymers (MIPs) are highly effective adsorbent for the extraction of chlorogenic acid from complex matrices. Currently, there is a lack of comprehensive review article that consolidate the methods utilized for the purification of chlorogenic acid through molecular imprinting. In this context, we have surveyed the common approaches employed in preparing MIPs specifically designed for the analysis of chlorogenic acid, including both conventional and newly developed. This review discusses the advantages, limitations of polymerization techniques and proposed strategies to produce more efficient MIPs for chlorogenic acid enrichment in complex samples. Additionaly, we present advanced imprinting methods for designing MIPs, which improve the adsorption capacity, sensitivity and selectivity towards chlorogenic acid.

Molecular dynamics simulations in pre-polymerization mixtures for peptide recognition.

CONTEXT: Molecularly imprinted polymers (MIPs) have promising applications as synthetic antibodies for protein and peptide recognition. A critical aspect of MIP design is the selection of functional monomers and their adequate proportions to achieve materials with high recognition capacity toward their targets. To contribute to this goal, we calibrated a molecular dynamics protocol to reproduce the experimental trends in peptide recognition of 13 pre-polymerization mixtures reported in the literature for the peptide toxin melittin. METHODS: Three simulation conditions were tested for each mixture by changing the box size and the number of monomers and cross-linkers surrounding the template in a solvent-explicit environment. Fully atomistic MD simulations of 350 ns were conducted with the AMBER20 software, with ff19SB parameters for the peptide, gaff2 parameters for the monomers and cross-linkers, and the OPC water model. Template-monomer interaction energies under the LIE approach showed significant differences between high-affinity and low-affinity mixtures. Simulation systems containing 100 monomers plus cross-linkers in a cubic box of 90 Å3 successfully ranked the mixtures according to their experimental performance. Systems with higher monomer densities resulted in non-specific intermolecular contacts that could not account for the experimental trends in melittin recognition. The mixture with the best recognition capacity showed preferential binding to the 13-26-α-helix, suggesting a relevant role for this segment in melittin imprinting and recognition. Our findings provide insightful information to assist the computational design of molecularly imprinted materials with a validated protocol that can be easily extended to other templates.

Molecularly Imprinted Polymeric Nanoparticles as Drug Delivery System for Tenofovir, an Acyclic Nucleoside Phosphonate Antiviral.

A molecularly imprinted polymer of Tenofovir (1), an FDA-approved acyclic nucleoside phosphonate with antiviral activity, was synthesized using a non-covalent approach. A pre-polymerization complex was formed between (1) and DMAEMA and in-house synthetic N1-[(2-methacryloyloxy)ethyl] thymine, with EGDMA as a cross-linker in an MeCN/H2O (9:1, 1:1) mixture as a porogen, giving an imprinting factor (IF) of 5.5 at 2.10-5 mol/L. Binding parameters were determined by the Freundlich-Langmuir model, Qmax and Ka, and well as the particle morphology for MIP and NIP. Finally, the release profiles, for MIP and NIP, were obtained at 25 °C and 37 °C, which is body temperature, in a phosphate buffer saline, pH 7.4, mimicking the blood pH value, to determine the potential sustained release of our polymeric materials.

Enhanced detection of 4-nitrophenol in drinking water: ECL sensor utilizing velvet-like graphitic carbon nitride and molecular imprinting.

In this work, a molecularly imprinted electrochemiluminescence (ECL) sensor was developed for selective detection of 4-nitrophenol (4-NP) in drinking water for the first time. By synthesizing velvet-like graphitic carbon nitride (V-g-C3N4) via one-step thermal polycondensation and integrating it with a molecularly imprinted polymer (MIP), the ECL sensor was fabricated. The MIP-modified V-g-C3N4 composites (MIP/V-g-C3N4) were synthesized using a sol-gel method with 4-NP as the template molecule. Under optimal conditions, the ECL sensor exhibited a wide detection range (5 × 10-10-1 × 10-5 mol/L) and a low detection limit (1.8 × 10-10 mol/L). In testing with actual drinking water samples, it displayed high accuracy (recoveries for intraday and inter-day: 93.50-106.2% and 97.00-107.3%, separately) and precision (RSDs for intraday and inter-day: 1.54-4.59% and 1.53-4.28%, respectively). The developed MIP-based ECL sensor demonstrated excellent selectivity, stability, and reproducibility, offering a promising and reliable approach for highly sensitive and selective determination of 4-NP in drinking water.

Fabrication of fluorescence probe based on molecularly imprinted polymers on red emissive biomass-derived carbon dots coupled with smartphone readout for tyramine determination in fermented meat products.

A fluorescence probe based on molecularly imprinted polymers on red emissive biomass-derived carbon dots (r-BCDs@MIPs) was developed to detect tyramine in fermented meat products. The red emissive biomass-derived carbon dots (r-BCDs) were synthesized by the one-step solvothermal method using discarded passion fruit shells as raw materials. The fluorescence emission peak of r-BCDs was at 670 nm, and the relative quantum yield (QY) was about 2.44%. Molecularly imprinted sensing materials were prepared with r-BCDs as fluorescent centers for the detection of trace tyramine, which showed a good linear response in the concentration range of tyramine from 1 to 40 µg L-1. The linear correlation coefficient was 0.9837, and the limit of detection was 0.77 µg L-1. The method was successfully applied to the determination of tyramine in fermented meat products, and the recovery was 87.17-106.02%. The reliability of the results was verified through high-performance liquid chromatography (HPLC). Furthermore, we combined the r-BCDs@MIPs with smartphone-assisted signal readout to achieve real-time detection of tyramine in real samples. Considering its simplicity and convenience, the method could be used as a rapid and low-cost promising platform with broad application prospects for on-site detection of trace tyramine with smartphone-assisted signal readout.