Molecularly Imprinted Polymers

Thermal sensing of syringic acid in food samples via molecularly imprinted polymers synthesized from bio-based deep eutectic solvents as monomers

Sensing syringic acid in food samples is highly valuable in food quality control due to its health promoting effects. To this purpose, syringic acid MIPs aligning with green chemistry have been developed by employing a bio-based functional monomer as DES and ethanol-water as porogen. MIP was implemented into a low-cost thermal readout platform as functional layer utilizing carbon tape for deposition. The sensor was characterized using SEM, IR, TGA and laser diffraction and its performance was evaluated through loading assays with syringic acid solutions, selectivity studies using structural analogues and food components, and quantification of syringic acid in thyme and walnut benchmarked by LC-MS. This work is the first to accurately quantify a molecular target using thermal readout with resulting LOD and LOQ of 0.28 ± 0.06 and 0.84 ± 0.18 μM respectively, linear ranges between 0.5 - 2.5 μM and 2.5 - 17.5 μM and recoveries ranging between 96.0 - 111 %.

From traditional to modern: Nanotechnology-driven innovation in mycotoxin sensing for Chinese herbal medicines

Mycotoxin contamination in Chinese herbal medicines (CHMs) is a pressing concern that jeopardizes their quality and safety, despite their widespread therapeutic use. Conventional detection methods are often limited by complexity, cost, and sensitivity, particularly in resource-limited settings. This gap in effective and efficient mycotoxin detection necessitates a comprehensive review that explores innovative solutions to enhance the safety and efficacy of CHMs. Advancements in nanomaterials and related advanced sensing techniques have emerged as a beacon of hope. Therefore, this review aims to fill the knowledge gap by providing a comprehensive overview of the latest developments in mycotoxin detection in CHMs, spotlighting the transformative role of nanomaterials and advanced sensing techniques. This review stands out for its in-depth exploration of functional nanomaterials across dimensions and their innovative applications in mycotoxin detection. Its innovation stems from a holistic approach that not only surveys current technologies but also charts a forward-looking path, emphasizing novel nanomaterial development, refined pretreatment, and advanced biosensing for on-site detection. It delves into the integration of nanomaterials with advanced sensing technologies, discussing the advantages and limitations of these approaches. A significant innovation of this review lies in the nuanced integration of nanomaterials with machine learning and artificial intelligence, revealing untapped potential for accuracy enhancement. Through this synthesis of knowledge, we hope to inspire further research and development in this critical area, ensuring the continued safe use of CHMs in traditional medicine practices.

Detection of antibiotic sulfamethoxazole residues in milk using a molecularly imprinted polymer-based thermal biosensor

Antibiotic resistance is a growing concern, partly due to inadequate inspections in the food safety chain. The accumulation of antibiotics like sulfamethoxazole (SMX) in animal products contributes to the rise of resistant microorganisms, posing a global health challenge. This work focuses on developing a thermal sensor to quickly and affordably detect SMX residues in milk samples. Molecularly imprinted polymers (MIPs) were synthesized and immobilized on an aluminum chip to measure thermal changes using the heat-transfer method (HTM). The sensor's detection limit in calcium chloride solutions was 261 ± 12 pmol L-1, well below regulatory limits for sulfonamides in dairy. The sensor also showed good selectivity when tested against antibiotics from different classes, and good performances in spiked milk samples. These results indicate that the thermal sensor provides a sensitive, low-cost alternative for detecting sulfamethoxazole traces in dairy products, contributing to improved food safety.

Advancements and prospects of molecularly imprinted polymers as chemical sensors: A comprehensive review

The scientific literature on molecularly imprinted polymers (MIPs) has grown significantly in the past decades, reflecting an increasing interest in their potential applications. MIPs are valued for their ability to selectively detect a broad range of analytes and mimic biological recognition in different environmental conditions. This review utilises data (Scopus data from 2010 to 2024) from a bibliometric visualisation with VOSviewer (version 1.6.2) to identify trends and research hotspots in developing MIP-based sensors. The findings from this review indicated notable advancements in molecular imprinting technology (MIT) and the challenges MIP technology faces. It also discusses how various optimisation preparation techniques can be used to overcome the inherent limitations of MIP synthesis. The review also presents a case investigation and suggests classifying MIPs as chemosensors (chemical sensors) rather than biosensors to resolve the confusion and classification difficulties encountered in the existing literature on MIP sensors. It also addresses critical issues regarding the paradoxical lack of MIP-based sensors in the commercial market despite a marked increase in scientific output. The review outlines future research directions to enhance MIP sensor technology further. It emphasises the need for more collaboration between academia and industry to bridge existing gaps and accelerate commercialisation.

Design of hybrid aptamer-molecularly imprinted polymer nanoparticles for selective binding of oxidized low-density lipoprotein in an ELISA-mimic system

Oxidized low-density lipoprotein (oxLDL) is the leading cause of atherosclerosis and cardiovascular disease development. An enzyme-linked immunosorbent assay (ELISA)-mimic system for sensitive and specific oxLDL determination was developed using selective aptamer-molecularly imprinted polymer nanoparticles (AP-MIP NP) coupled with an immunology-based colorimetric assay. The AP-MIP NP were synthesized using solid-phase molecular imprinting by incorporating aptamers into the MIP NP cavities. This resulted in AP-MIP NP with diameters of 108 ± 28 nm. For AP-MIP NP-ELISA-mimic assay development, the surface of a microplate was coated with the novel AP-MIP NP capture receptors at a concentration of 0.1 mg mL-1 to capture oxLDL. The reaction time between AP-MIP NP and oxLDL was 20 min. Horseradish peroxidase conjugated anti-oxLDL polyclonal antibody at a concentration of 0.6 μg mL-1 was used as the detection antibody, with a linear response ranging from 24.72 to 1,600 μg dL-1. The recovery accuracy was 89-106 %. Within-run precision was 3.3-6.7 % of the coefficient of variation, while between-day precision was 3.8-7.1 %. The AP-MIP NP-coated wells were stored at room temperature for one month without a loss of binding ability, retaining over 91 % binding ability after three regeneration cycles. Human serum diluted 1:10 and analyzed by the AP-MIP NP-ELISA-mimic assay showed high correlation with conventional ELISA (R2 = 0.9779). This assay achieved rapid results within 95 min, compared to ELISA at 195 min. The high binding ability and selectivity of the AP-MIP NP shows promise as a selective material against oxLDL for the ELISA-mimic system and other applications.

Construction of a sensing platform for rapid visual detection of oxytetracycline using AIE/Eu MOFs-based molecularly imprinted ratiometric fluorescent probe

Rapid and accurate field testing for oxytetracycline (OTC) is crucial for ensuring food safety and monitoring environmental pollution. Herein, we report the construction of an aggregation-induced emission metal-organic frameworks (MOFs)-mediated molecularly imprinted ratio metric fluorescent sensor (AIE/Eu@MIPs) for the rapid and selective detection of OTC with high sensitivity. AIE MOFs with ultra-high quantum yield were utilized as the blue fluorescence emission carriers, thus avoiding any compromise between convenience and cost-effectiveness. The detection sensitivity was significantly enhanced by modifying the fluorescence signals, driven by the combined effects of the inner filter effect (IFE) and antenna effect (AE). The detection limit was as low as 21 nM (about 9.67 μg/kg). More importantly, a portable optical sensing platform integrating AIE/Eu@MIPs was developed for visual detection of OTC. The developed probe and portable device-based sensing platform demonstrate considerable potential for on-site detection of OTC in real-world applications.

Fabrication of tailored imprinted layer and cladded layer on magnetic nanomaterials with enhanced specificity for recognition of PFOS

BACKGROUND

Perfluorooctane sulfonate (PFOS) is a persistent organic pollutant with significant risks to ecosystems and human health. Magnetic molecularly imprinted polymers (MIPs) provide a promising solution for selectively extracting PFOS from contaminated water. However, while bifunctional monomer imprinting improves the imprinting effect by introducing diverse functional groups, it can also increase non-specific adsorption. To address this problem, a surface cladding strategy was applied after polymerization, forming an inert cladding layer to reduce non-specific binding and improve specificity.

RESULTS

The magnetic MIPs with a cladding layer (Fe3O4@PFOS-cMIPs) exhibited enhanced adsorption performance, achieving a high adsorption capacity of 135.1 mg g-1, an imprinting factor of 3.19, and a selectivity factor greater than 1.3, surpassing most reported PFOS-MIPs. The interactions between Fe3O4@PFOS-cMIPs and PFOS were confirmed to be a synergistic combination of electrostatic and hydrophobic interactions, as evidenced by FTIR analysis, zeta potential measurements, and pH studies. Additionally, Fe3O4@PFOS-cMIPs demonstrated excellent reusability, with stable performance across six adsorption-desorption cycles using a regeneration solution of acetone and NaCl. Furthermore, when coupled with LC-MS, Fe3O4@PFOS-cMIPs successfully detected trace levels of PFOS in complex environmental water samples. The method demonstrated high precision (RSD, 6.0 %), excellent recoveries (90.9 %-103.3 %), a low limit of detection (LOD, 0.06 ng L-1), and an enrichment factor of 299.

SIGNIFICANCE

This study presents a practical and efficient strategy for developing magnetic MIPs with enhanced molecular recognition. The enhanced specificity and adsorption capacity highlight the strong potential of these MIPs for the targeted extraction of PFOS from various contaminated water sources, offering significant contributions to environmental analysis and remediation.

Machine learning-enhanced detection of chlorpyrifos using molecularly imprinted polymer-coated optical fibers

This paper explores the use of large core declad optical fibers coated with molecularly imprinted polymers for chlorpyrifos detection, a key marker of organophosphate pesticides. The performance of sensor is evaluated using artificial neural networks and principal component analysis. By varying the declad length, the performance of molecularly imprinted polymer-coated fibers is compared to uncoated fibers, and both are used to identify commercial and pure samples of chlorpyrifos pesticides. Molecularly imprinted polymer-coated declad fiber sensors particularly those with longer declad lengths, exhibit significantly lower detection limits and higher sensitivity. The obtained maximum sensitivity, and minimum detection limit at 4 cm declad fiber length are 0.0027 mV/nM and 60.70 nM respectively. The results obtained also demonstrate that the artificial neural network can make an accurate prediction and the principal component analysis validates the efficacy of our molecularly imprinted polymer-coated fibers in chlorpyrifos detection.

Theranostic advances and the role of molecular imprinting in disease management

Molecular imprinting has become an effective technology in the realm of diagnosing diseases, providing unparalleled specificity and sensitivity. This method is a promising trend in current medical research. This review examines the utilization of molecularly imprinted polymers (MIPs) in theranostic that integrates diagnostic functionalities for personalized medicine. The present work briefly discusses the fundamental concepts of molecular imprinting and how it has evolved into a versatile platform. Subsequently, the utilization of MIPs in the advancement of biosensors is focused, specifically emphasizing their contribution to the detection and diagnosis of diseases. The therapeutic potential of MIPs, focusing on targeted drug delivery and controlled release systems and the integration of MIPs into theranostic platforms is explored through case studies, showcasing the technology's ability to simultaneously diagnose and treat diseases. Finally, we address the current challenges facing MIPs and discuss future perspectives, emphasizing the potential of this technology to revolutionize the next generation.

Hybrid Poly(Methacrylic Acid-Co-Acrylamide)-Polythiophene Nanofibers for Salivary Diagnosis of Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is a major health concern in high-risk regions globally, with rising mortality rates indicating the urgent need for early detection tools. This study presents an innovative point-of-care (POC) diagnostic tool using disposable microelectrodes to detect cholic acid, a crucial OSCC biomarker, in human saliva. By combining a poly(methacrylic acid-co-acrylamide) copolymer (CoP) with polythiophene (PTh) nanofibers as selective coatings for disposable, screen-printed carbon electrodes (SPCE), the developed CoP-PTh/SPCE sensors demonstrate exceptional performance. Using impedance spectroscopy and voltammetric techniques, the electrochemical oxidation of cholic acid in solution and saliva samples is investigated. The CoP-PTh/SPCE sensors exhibit an outstanding sensitivity of 1.05 µA cm-2 nm-1 (74.2 µA µm-1), a detection limit (LOD) of 0.240 nm, and a quantification limit (LOQ) of 0.727 nm, demonstrating their superior capabilities. Additionally, these sensors exhibit remarkable selectivity against structurally similar compounds such as cholesterol and various salivary analytes. The practical application of CoP-PTh/SPCE sensors is realized through a 97.67±1.08% recovery of spiked cholic acid concentrations in human saliva samples. This study highlights the potential of CoP-PTh/SPCE sensors for reliable, efficient, and non-invasive POC testing, offering a promising solution for the early diagnosis of poorly differentiated OSCC.

Determination of cyclopiazonic acid in food samples by using molecularly imprinted polymers based on magnetic halloysite nanotubes

A fast, accurate, and simple method of molecularly imprinted solid-phase extraction from magnetic molecularly imprinted polymers (m-MISPE) has been developed for the determination of cyclopiazonic acid (CPA) in food samples. For the synthesis of the magnetic molecularly imprinted polymers, the core-shell method through microwave irradiation was employed. Firstly, as the core halloysite nanotubes were functionalized with magnetite nanoparticles. Then, the molecular imprinted polymer (MIP) shell was created around the halloysite nanotube cores by microwave induction. In the MIP synthesis for the template molecule, an analogous compound in structure to that of CPA has been used as a surrogate molecule to reduce the costs and toxicity produced by the toxin. Besides, washing and elution m-MISPE steps were optimized to eliminate the interferences. Cross-reactivity of the m-MISPE proposed method has been tested with different mycotoxins to determine the selectivity of the polymer towards CPA (imprinting factor (IF): MIP/NIPCPA = 3,1; MIP/NIPZON = 2,2; MIP/NIPAOH = 1,7; MIP/NIPOCRA = 0,8). Finally, the m-MISPE method has been successfully applied to rice flour samples at three different concentration levels, 75, 120, and 200 μg/L, whose recoveries were 83, 97, and 93% and their RDS were 1, 2, and 2, respectively. The detection and quantification limits were 11.1 and 36.5 µg/kg respectively. This procedure is considered an easy and economical analytical way to determine CPA in food in routine laboratories of any food quality and is easy to implement versus the current methods in the determination of this mycotoxin.

Organic Electrochemical Transistors with Molecularly Imprinted Polymer Electrodes for Rapid Detection of Perfluorooctanoic Acid

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants linked to adverse health effects, and there is a need for sensors that can detect PFAS in challenging environments. Electrochemical sensors offer significant potential for achieving cost-effective, rapid, and real-time detection of PFAS, particularly in comparison to current detection techniques, which rely on costly chromatographic methods. Here, we report that organic electrochemical transistors (OECTs) containing a molecularly imprinted polymer (MIP) gate electrode can selectively detect perfluorooctanoic acid (PFOA) in seawater. We prepared a molecularly imprinted polyaniline (PANI) gate electrode by polymerizing aniline onto filter paper in the presence of PFOA, followed by rinsing to remove the PFOA. When used as a gate electrode in an organic electrochemical device (OECT), the presence of PFOA produced a measurable change in the OECT source-drain current due to adsorption of PFOA onto the gate electrode, which reduced capacitance and increased impedance. Other molecules produced a weak or no response. Specifically, we show that the device responds strongly to PFOA but only weakly to perfluoropropionic acid (PFPrA), perfluorohexanoic acid (PFHxA), and surfactant 4-dodecylbenzenesulfonic acid (DBSA). The device is also able to selectively detect PFOA in mixtures containing these other PFAS or surfactants. We achieved a detection limit of 1.6 parts per trillion (ppt) or 3.86 × 10-12 M, below the regulatory advisory level of 70 ppt set by the United States Environmental Protection Agency for PFOA. This work demonstrates low-cost sensors capable of rapid and molecularly specific detection of PFOA, which can potentially lead to low-cost sensors for monitoring the concentrations of PFOA and other PFAS in seawater and other challenging environments.

Enhanced Redox-Flow Desalination with Polyaniline-Modified Electrode

Electrode materials are crucial for the performance of redox-flow desalination (RFD), a promising technology for addressing the increasing global demand for freshwater. However, the lack of efficient and stable electrode options has hindered its widespread application. To overcome this limitation, we developed polyaniline (PANI)-modified graphite foil electrodes, achieving a significant reduction in energy consumption for RFD (up to 78.8%). Electrochemically deposited onto the surface of graphite foil, the PANI film improves redox behavior and enhances desalination performance. At a current density of 3 mA cm-2, energy consumption decreased from 125.44 to 39.26 KJ mol-1 with the PANI modification and from 207.73 to 40.11 KJ mol-1 at 6 mA cm-2. The modified electrodes also achieved salt removal rates of 1.60 and 3.17 μmol cm-2 min-1 at the respective current densities of 3 and 6 mA cm-2. In addition, the PANI film demonstrated excellent multicycle and long-term stability. These findings pave the way for the development of high-performance RFD systems and have implications for other electrochemical desalination technologies.

In silico design of magnetic, polymeric synthetic receptor targeting clumping factor A, for the specific capture and detection of Staphylococcus aureus

Rapid diagnosis of Staphylococcus aureus (S. aureus) is critical for both therapy and infection control programs. Currently available rapid bacterial detection methods such as polymerase chain reaction (PCR) requires expensive equipment and trained personnel, whereas, enzyme-linked immunosorbent assay (ELISA) requires antibodies and thus, suffer from limitations such as limited reagent stability. Herein, we used stable, cost-effective alternates to the antibodies known as synthetic antibodies i.e., molecularly imprinted polymers (MIPs). In this study, polymeric synthetic receptor commonly known as MIPs were layered onto magnetic nanoparticles, specifically designed for the detection of S. aureus through the binding interaction with its surface biomarker- clumping factor A (ClfA). This approach offers a low limit of detection (LOD) of 102 colony-forming units per mL (CFU/mL) and a wide linear detection range (103 to 108 CFU/mL) for S. aureus. Briefly, ClfA gene was cloned, expressed and protein was purified using Ni-NTA affinity chromatography and anion-exchange chromatography. Magnetic nanoparticles were initially synthesized and coated with silica, followed by introduction of aldehyde groups for immobilization through imine bonding. ClfA was then immobilized onto the functionalized nanoparticles, serving as a template for MIP synthesis. To determine a monomer combination with high binding capacity and specificity for ClfA, docking studies were performed using Autodock 4.2. The polymerization process employed selected monomer combination, yielding MIP tailored to recognize ClfA. The binding properties of the MIP were extensively investigated, demonstrating specificity and selectivity for ClfA over non-specific proteins. Furthermore, the clinical utility of the MIP was assessed by examining its binding with ClfA in serum samples. The present study contributes to the advancement of specific and efficient tools for the S. aureus diagnostics, based on a virulence biomarker, ClfA, emphasizing the potential applications of molecularly imprinted magnetic nanoparticles for microbial detection and their virulence.

Rational design of gold nanoparticle-based chemosensors for detection of the tumor marker 3-methoxytyramine

In this study, we combined computational modeling, simulations, and experiments to design gold nanoparticle-based receptors specifically tailored for the NMR detection of 3-methoxytyramine (3-MT), a prognostic marker for asymptomatic neuroblastoma. We used short steered MD simulations to rank a library of 100 newly functionalized, tripeptide-coated AuNPs for their ability to recognize 3-MT. Validation of the computational analysis was performed on a subset of synthesized tripeptide-coated nanoparticles, showing a strong correlation between the predicted and experimental affinities. Eventually, we tested the sensing performance using nanoparticle-assisted NMR chemosensing, a technique which relies on magnetization transfer within a nanoparticle-host/analyte-guest complex to isolate the sole NMR signals of the analyte. This approach led to the identification of novel chemosensors that exhibited better performance compared to existing ones, lowering the limit of detection below 25 μM and demonstrating the utility of this integrated strategy.

A general method to improve imprinting efficiency in surface protein imprinting by enhanced pre-assembly

Surface protein-imprinted nanoparticles may replace the expensive and unstable antibodies in biomedical applications but still suffers from a low imprinting efficiency. A main reason may be the insufficient pre-assembly between monomers and template protein in surface imprinting using the conventional surface graft polymerization method. Increasing monomer concentrations enhances pre-assembly, but leads to agglomeration of the particles. To solve the dilemma, here an initiating system consisting of surface-immobilized glucose oxidase and horseradish peroxidase, glucose and acetylacetone was used to synthesize the imprinted coatings. No agglomeration occurs even at high monomer concentrations because of the localized polymerization. When surface imprinting of lysozyme over silica nanoparticles, both adsorption capacity and imprinting factor increase with increasing monomer concentration, because of the enhanced pre-assembly. This strategy was further combined with the "shape-memorable imprint cavity" strategy in which the conventional crosslinker is replaced with a peptide crosslinker capable of undergoing pH-induced helix-coil transition. The resulting surface lysozyme-imprinted silica nanoparticles exhibit high adsorption capacity, high imprinting factor, high selectivity, good reusability, easy and complete template removal under mild conditions, and fast rebinding kinetics. Surface imprinting of other proteins with high imprinting efficiency were also successfully carried out, demonstrating the generality of the strategy. STATEMENT OF SIGNIFICANCE: Surface protein-imprinted nanoparticles have emerged as promising artificial antibodies, but still suffering from low imprinting efficiency, primarily due to insufficient pre-assembly between functional monomers and template proteins. Increasing monomer concentrations enhances pre-assembly but causes particle agglomeration. Here the dilemma was solved by using an initiating system consisting of surface-immobilized glucose oxidase/horseradish peroxidase, glucose, and acetylacetone to achieve localized polymerization. Imprinting efficiency was significantly improved because of enhanced pre-assembly. This strategy was further combined with the "shape-memorable imprint cavity" strategy. Lysozyme-imprinted nanoparticles with high capacity (146.4 mg g-1), high imprinting factor (13.94), reusability, and fast rebinding kinetics was synthesized. Surface imprinting of other proteins with high imprinting efficiency were also successfully carried out, demonstrating the generality of the strategy.

Zwitterionic Molecularly Imprinted Hairy Cellulose Nanocrystals Enable Selective Vancomycin Removal

Access to free, off-target, and nontherapeutic doses of antibiotics is a key driving factor in the emergence of antimicrobial resistance (AMR). Intravenously (IV) administered vancomycin (VAN) is among the last-line antibiotics for treating infections caused by multidrug-resistant Gram-positive bacteria. A fraction of the total IV dose unwantedly reaches the gastrointestinal tract, driving AMR. Selective VAN removal from the complex intestinal fluid may reduce the probability of AMR emergence; however, it remains a significant challenge due to the competitive adsorption of other species. Here, we engineer novel VAN-imprinted polymerized zwitterionic hairy cellulose nanocrystals (ViPZ-HCNC) that selectively capture VAN with a removal capacity of ∼ 235 mg g-1 at an imprinting factor of ∼ 7.5. ViPZ-HCNC provide the first nanocellulose-based material with an excellent selectivity for VAN against lysine, lysozyme, and bovine serum albumin, which efficiently remove VAN from calcium ion-containing solutions and simulated intestinal fluids. Additionally, ViPZ-HCNC are not toxic against NIH/3T3 murine fibroblast cells. We envision that ViPZ-HCNC may pave the way for developing soft materials that selectively remove off-target VAN from a broad range of media, preventing VAN resistance evolution. This research is a step forward in addressing the long-lasting AMR challenge using a biobased platform.

Rapid and simple on-site salmonella detection in food via direct sample loading using a lipopolysaccharide-imprinted polymer

Salmonella is a major foodborne pathogen that causes salmonellosis, which is characterized by symptoms such as diarrhea, fever, and abdominal cramps. Existing methods for detecting Salmonella, such as culture plating, ELISA, and PCR, are accurate but time-consuming and unsuitable for on-site applications. In this study, we developed a rapid and sensitive electrochemical sensor using a molecularly imprinted polymer (MIP) to detect Salmonella typhimurium (S. typhimurium) by targeting lipopolysaccharides (LPS). Polydopamine (PDA) was used as the polymer matrix because of its cost-efficiency and functional versatility. The sensor demonstrated high sensitivity and selectivity, with a detection limit of 10 CFU/mL and a linear response over the 10²-10⁸ CFU/mL range. The specificity of the sensor was validated against other gram-positive and gram-negative bacteria and showed no significant cross-reactivity. Furthermore, the sensor performed effectively in real food samples, including tap water, milk, and pork, without complex preprocessing. These results highlight the potential of the LPS-imprinted MIP sensor for practical on-site detection of S. typhimurium, improving food safety monitoring and preventing outbreaks in food-handling environments.

Elimination of non-specific adsorption in the molecularly imprinted membrane: application for tetracycline detection

A vital challenge in using imprinted membranes for selective sensing is their non-specific adsorption (NSA). In this study, a novel, rapid, and green approach of NSA-free molecularly imprinted membrane (MIM) preparation was proposed. Sodium alginate was employed as a functional polymer (to interact with the template) and as a membrane matrix, then cross-linked with calcium before template removal to block the unreacted groups, followed by exposure to phosphate to chelate any remaining sites. Unlike the non-imprinted membrane (NIM), which is prepared similarly to MIM and lacks the template cavities, the MIM demonstrated exceptional imprinting factor (IF) (Q(NIM) ≈ 0 mg/g) compared to the initial IF of around 4 before NSA suppress, and a selectivity factor over 10 times greater than that of existing MIMs in the literature. The NSA-free MIM was used as a ready-to-use sensor for spectro-fluorescence and smartphone-based fluorescence detection of tetracycline (TC), achieving detection limits of 0.005 mg/L and 0.015 mg/L, respectively, which were below the maximal acceptable concentrations of TC in real samples. The detection of TC in milk and honey samples using the NSA-free MIM showed significant recoveries (86-101%) compared to those found by MIM before NSA supress (114-122%). The proposed methodology serves as an inspiration for extending NSA removal strategies to other MIMs based on various anionic polymers, including carboxylate, sulfonate, phosphonate, and phenolate anionic groups.

Recent advances in bioreceptor-based sensing for extracellular vesicle analysis

Extracellular vesicles (EVs) are nanoscale, membrane-bound structures secreted by various cell types into biofluids. They show great potential as biomarkers for disease diagnostics, owing to their ability to carry molecular cargo that reflects their cellular origin. However, the inherent heterogeneity of EVs in terms of size, composition, and source presents significant challenges for reliable detection and analysis. Recent advances in bioreceptor-based biosensor technologies provide promising solutions by offering high sensitivity and specificity in EV detection and characterization. These technologies address the limitations of conventional methods, such as ultracentrifugation and bulk analysis. Biosensors utilizing antibodies, aptamers, peptides, lectins, and molecularly imprinted polymers enable precise detection of EV subpopulations by targeting specific EV surface markers, including proteins, lipids, and glycans. Additionally, these biosensors support multiplexed and real-time analysis while preserving the structural integrity of EVs. This review highlights the transformative potential of combining modern biosensing tools with bioreceptor technologies to advance EV research and diagnostics, paving the way for innovations in disease diagnostics and therapeutic monitoring.

Nature-Inspired Engineering Separation Materials and Devices

Separation is a fundamental process in natural living systems. Their separation capabilities have inspired the design of various separation materials and devices. Despite some progress having been made, a comprehensive overview is still lacking. In this Perspective, we first review the development of separation technologies. We then summarize some typical living systems exhibiting superior separation capabilities from compositions and microstructures to separation mechanisms. Next, we highlight key advancements in nature-inspired separation materials and integrated devices. Finally, we propose future research directions and opportunities, emphasizing the importance of physical and chemical design and internal and external stimulus regulation. These nature-inspired materials and devices show great potential in biomedicine, environmental remediation, energy conversion, food safety, and analysis testing.

Printable molecule-selective core-shell nanoparticles for wearable and implantable sensing

Wearable and implantable biosensors are pioneering new frontiers in precision medicine by enabling continuous biomolecule analysis for fundamental investigation and personalized health monitoring. However, their widespread adoption remains impeded by challenges such as the limited number of detectable targets, operational instability and production scalability. Here, to address these issues, we introduce printable core-shell nanoparticles with built-in dual functionality: a molecularly imprinted polymer shell for customizable target recognition, and a nickel hexacyanoferrate core for stable electrochemical transduction. Using inkjet printing with an optimized nanoparticle ink formulation, we demonstrate the mass production of robust and flexible biosensors capable of continuously monitoring a broad spectrum of biomarkers, including amino acids, vitamins, metabolites and drugs. We demonstrate their effectiveness in wearable metabolic monitoring of vitamin C, tryptophan and creatinine in individuals with long COVID. Additionally, we validate their utility in therapeutic drug monitoring for cancer patients and in a mouse model through providing real-time analysis of immunosuppressants such as busulfan, cyclophosphamide and mycophenolic acid.

Dual-Functional Antenna Sensor for Highly Sensitive and Selective Detection of Isopropanol Gas Using Optimized Molecularly Imprinted Polymers

Accurate monitoring of isopropanol (IPA) levels is crucial for safety in industrial and laboratory settings, as high concentrations can lead to serious health issues. In this study, we present, for the first time, a dual-functional antenna sensor capable of high-performance IPA gas detection with concentration estimation and uninterrupted wireless communication, using optimized molecularly imprinted polymer (MIP)/multiwalled carbon nanotube (MWCNT)-based sensing materials. Comprehensive characterization of these materials confirms the successful formation and homogeneity of the composites. Furthermore, the electrical and gas-sensing properties of the sensing materials were evaluated using functionalized interdigitated electrode (IDE)-based sensing structures, optimized for high sensitivity, were functionalized to evaluate the electrical and gas-sensing properties of the materials. These IDE structures, which acted as impedance-varying components during operation, were coupled with a single-port monopole antenna to develop a highly sensitive and selective gas sensor while maintaining uninterrupted communication services. The results showed that the fabricated sensor platform exhibits strong selectivity, sensitivity, and stability for IPA detection at room temperature, effectively distinguishing it from other interference gases. In addition, using the same sensing material, we demonstrated that the antenna-based gas sensor exhibited higher sensitivity than the chemiresistive sensor, achieving a detection limit (18.8 ppm) below the safety thresholds for IPA. Moreover, the antenna's radiation pattern and communication capabilities remained unaffected, ensuring uninterrupted functionality. Detailed optimization process and the sensing mechanism for a novel MIP-based selective antenna gas sensor, supported by both structural and electrical characterizations could serve as a milestone for future studies and the advancement of next-generation sensors.

Electrogenerated Chemiluminescence Coupled with Molecularly Imprinted Polymer for Sensitive and Selective Detection of N,N-Dimethyltryptamine

A simple and efficient approach that combined electrogenerated chemiluminescence (ECL) and molecularly imprinted polymers (MIPs) for selective and sensitive detection of the hallucinogenic drug N,N-dimethyltryptamine (DMT) was developed. ECL, one of the most sensitive analytical techniques for ultratrace analyte detection, offers the advantage of light-free spectroscopic analysis initiated by electrochemistry. MIPs, on the other hand, provide specific binding sites, allowing the target analyte to become selectively imprinted within the polymer matrix. In this study, an ECL coupled-MIP sensor was fabricated using para-aminobenzoic acid (p-ABA) as the monomer and DMT as the template molecule. The MIP was electropolymerized onto a glassy carbon electrode coated with a Nafion film entrapping [Ru(bpy)3]2+ species. Following elution, the imprinted sites were reoccupied by DMT, generating ECL signals in a phosphate buffered solution during anodic potential scanning. The ECL-MIP sensor demonstrated a wide dynamic range for DMT detection, from 0.5 to 300 μM, with an estimated detection limit of 0.5-1.0 μM (S/N = 3). The sensor's reproducibility, stability, and selectivity were also evaluated. Finally, density functional theory was employed to investigate the structure-property relationship of the p-ABA-DMT interaction. This work demonstrated the potential of ECL coupled with MIP technology for identifying structurally related molecules, achieving enhanced selectivity with a simple and cost-effective design.

Magnetite Nanoparticles with High Affinity Toward Target Protein for Efficient and Facile Bio-Separation

Magnetite nanoparticles (Fe3O4 NPs) with molecular recognition capabilities offer significant potential for biomedical applications, yet existing surface protein imprinting methods often suffer from low efficiency. Herein, a surface enzyme-mediated polymerization strategy is exploited for surface imprinting of bovine serum albumin (BSA) onto Fe3O4 NPs. This method, compatible with all vinyl monomers and operable under mild conditions, enables imprinting at high monomer concentrations while preventing nanoparticle agglomeration. Notably, increasing the pre-polymerization solution concentration enhances the pre-assembly of functional monomers and template molecules, thereby improving imprinting efficiency. Furthermore, replacing conventional crosslinkers with a polyglutamic acid-based peptide crosslinker introduces a pH-responsive helix-coil transition, allowing complete template removal under mild conditions and increasing the adsorption capacity and imprinting factor to 139.8 mg g⁻¹ and 10.36, respectively. The resulting BSA-imprinted Fe₃O₄ NPs exhibits high selectivity, robustness, and rapid adsorption kinetics while maintaining strong magnetic responsiveness for easy separation. These features allows for the selective extraction of BSA from bovine fetal serum, demonstrating the potential of this approach for biomedical applications, particularly in bioseparations.

Unravelling the Potential of Zwitterionic Polymers in Molecular Imprinting

Molecularly imprinted polymers (MIPs) are a class of molecular receptors that are the closest imitation of biological receptors. They are often called "artificial enzymes". The capability of the MIPs to bind bioactive molecules under specific conditions creates molecular imprinting technology as having considerable potential for customized applications. Polymerization in the presence of a "template" molecule with the assistance of monomers, cross-linkers, and initiators leads to MIPs on extraction of the template molecule from the polymeric matrices. Conventionally neutral monomers were utilized for molecular imprinting. Recently, zwitterionic polymers, having innumerable advantages over nonionic polymers, were realized to be an advantageous choice as a polymeric matrix for imprinting. This review article presents an overview of sulfobetaine, carbobetaine, and phosphobetaine polymers as imprinting matrices for a range of template(s). Zwitterionic polymers are accomplished with biocompatibility, low cytotoxicity, negligible immunogenicity, systematic stability, and long circulation time, and can alleviate quick recognition by the immune system and delayed blood clearance from the body. They can be a fitting candidate for imprinting, especially of biomolecules. The molecular imprinting work on zwitterionic polymers is presented here, which will encourage researchers working in this area.

Dual surrogate imprinting: an innovative strategy for the preparation of virus-selective particles

This work involves the preparation of dual surrogate-imprinted polymers (D-MIPs) for the capture of SARS-CoV-2. To achieve this goal, an innovative and novel dual imprinting approach using carboxylated-polystyrene (PS-COOH) nanoparticles with a diameter of 100 nm and a SARS-CoV-2 Spike-derived peptide was carried out at the surface of amine-functionalized silica (PS-NH2) microspheres with a diameter of 500 nm. Firstly, PS-COOH nanoparticles with the same size and spherical shape as the SARS-CoV-2 virus were employed to form hemispherical indentations (HI) at the surface of the PS-NH2 microspheres (obtaining dummy particle-imprinted polymers, HI-MIPs). Next, a specific peptide sequence representing the Spike protein at the surface of the target virus was also used as the second template to generate specific peptide binding sites at the HI. Finally, the PS-COOH and the peptide were removed by several washing steps providing D-MIPs, comprising both dummy particle indentations (HI) and peptide binding sites. The D-MIPs and HI-MIPs were in-depth characterized via scanning electron microscopy (SEM), transmission electron microscope (TEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), and energy dispersive X-ray analysis (EDAX). 100% rebinding efficiency was achieved for the SARS-CoV-2 peptide with D-MIPs highlighting its specificity vs. non-peptide-imprinted control polymers (HI-MIPs), which only achieved a binding efficiency of <40.5%. D-MIPs also showed higher affinity than HI-MIPs towards real SARS-CoV-2 virus. Furthermore, lower rebinding percentages for both HI-MIPs (8.5%) and D-MIPs (6.9%) were obtained when incubated with an alternative peptide (i.e., characteristic for Zika virus) indicating a successful peptide imprinting process for the target SARS-CoV-2 peptide.

Formation of molecularly imprinted polymers: Strategies applied for the removal of protein template (review)

The key step in the entire molecularly imprinted polymer (MIP) preparation process is the formation of the complementary cavities in the polymer matrix through the template removal process. The template is removed using chemical treatments, leaving behind selective binding sites for target molecules within the polymer matrix. Other MIP preparation steps include mixing monomers and template molecules in the appropriate solvent(s), monomer-template complex equilibration, and polymerisation of the monomers around the template. However, template removal is the most important among all the preparation steps because the final structure, which can be accepted and recognised as the MIP, is obtained only after the template removal. A thorough analysis of the studies dedicated to MIP applications demonstrates that this MIP preparation step, namely the template removal, is relatively understudied. MIP template removal is especially challenging in the synthesis, where the molecular template is a macromolecule such as a protein. This review aims to provide a deliberate, systematic, and consistent overview of protein removal as the MIP template molecules. The most prevalent template removal methods are outlined for removing protein templates from electrochemically synthesised MIPs, particularly thin layers on electrodes used in electrochemical sensors. Five protein template removal approaches involving chemical treatment are highlighted, which include the utilisation of (i) chaotropic agents, (ii) salt, (iii) acidic cleavage, (iv) alkaline, and finally, (v) proteolytic treatment focusing on studies conducted over the past decade. In addition, we discuss the interactions driving the removal of protein templates in each approach and associated challenges. This review provides insights into MIPs protein template removal strategies while highlighting the prevalent issue of this understudied step of template removal.

Design and engineering of microenvironments of supported catalysts toward more efficient chemical synthesis

Catalytic species such as molecular catalysts and metal catalysts are commonly attached to varieties of supports to simplify their separation and recovery and accommodate various reaction conditions. The physicochemical microenvironments surrounding catalytic species play an important role in catalytic performance, and the rational design and engineering of microenvironments can achieve more efficient chemical synthesis, leading to greener and more sustainable catalysis. In this review, we highlight recent works addressing the topic of the design and engineering of microenvironments of supported catalysts, including supported molecular catalysts and supported metal catalysts. Six types of materials, including oxide nano/microparticle, mesoporous silica nanoparticle (MSN), polymer nanomaterial, reticular material, zeolite, and carbon-based nanomaterial, are widely used as supports for the immobilization of catalytic species. We summarize and discuss the synthesis and modification of supports and the positive effects of microenvironments on catalytic properties such as metal-support interaction, molecular recognition, pseudo-solvent effect, regulating mass transfer, steric effect, etc. These design principles and engineering strategies allow access to a better understanding of structure-property relationships and advance the development of more efficient catalytic processes.

Highly specific colorimetric detection of sarcosine using surface molecular imprinted Zn/Ce-ZIF

Despite significant progress in nanozyme research and the advancement of analytical techniques, the inherent lack of specificity for target analytes often limits their utility in analysis. Integrating specific recognition capabilities into inorganic nanomaterials, independent of biological catalysts or adaptors, represents a crucial breakthrough in the field. Detecting Sarcosine (Sar) in human urine has recently emerged as a non-invasive biomarker for prostate cancer (PCa), presenting a valuable diagnostic tool. This study introduces a novel method for embedding molecular imprinting sites directly onto the surface of a Zn/Ce-based zeolitic imidazolate framework (Zn/Ce-ZIF) nanozyme, facilitating the development of a highly specific colorimetric assay for precise Sar measurement. By utilizing the lanthanide metal cerium as the catalytic element and ZIF-8 as the structural scaffold, we synthesized spherical Zn/Ce-ZIF nanozymes with exceptional oxidase-like catalytic efficiency. The efficiency of molecular imprinting experiments and the ability of molecularly imprinted polymers (MIPs) to identify target molecules were significantly enhanced by using theortical calculations to screen suitable functional monomers. The molecularly imprinted nanozyme (Zn/Ce-ZIF@MIP) initiates a colorimetric oxidation reaction of 3,3',5,5'-tetramethylbenzidine (TMB), wherein the presence of Sar facilitates selective recognition and capture by the MIP shell, modulating the colorimetric response by hindering TMB's access to the catalytic site. An intelligent color extraction detection device has been developed for the rapid perception of Sar. This colorimetric sensing platform has been validated through the detection of Sar in simulated urine samples. Overall, the application of surface molecular imprinting enhances the functionality of nanozymes in analytical fields.

An In-Depth Review of Molecularly Imprinted Electrochemical Sensors as an Innovative Analytical Tool in Water Quality Monitoring: Architecture, Principles, Fabrication, and Applications

Molecularly imprinted electrochemical sensors (MI-ECSs) are a significant advancement in analytical techniques, especially for water quality monitoring (WQM). These sensors utilize molecular imprinting to create polymer matrices that exhibit high specificity and affinity for target analytes. MI-ECSs integrate molecularly imprinted polymers (MIPs) with electrochemical transducers (ECTs), enabling the selective recognition and quantification of contaminants. Their design features template-shaped cavities in the polymer that mimic the functional groups, shapes, and sizes of target analytes, resulting in enhanced binding interactions and improved sensor performance in complex water environments. The fabrication of MI-ECSs involves selecting suitable monomeric units (monomers) and crosslinkers, using a target analyte as a template, polymerizing, and then removing the template to expose the imprinted sites. Advanced methodologies, such as electropolymerization and surface imprinting, are used to enhance their sensitivity and reproducibility. MI-ECSs offer considerable benefits, including high selectivity, low detection limits, rapid response times, and the potential for miniaturization and portability. They effectively assess and detect contaminants, like (toxic) heavy metals (HMs), pesticides, pharmaceuticals, and pathogens, in water systems. Their ability for real-time monitoring makes them essential for ensuring water safety and adhering to regulations. This paper reviews the architecture, principles, and fabrication processes of MI-ECSs as innovative strategies in WQM and their application in detecting emerging contaminants and toxicants (ECs and Ts) across various matrices. These ECs and Ts include organic, inorganic, and biological contaminants, which are mainly anthropogenic in origin and have the potential to pollute water systems. Regarding this, ongoing advancements in MI-ECS technology are expected to further enhance the analytical capabilities and performances of MI-ECSs to broaden their applications in real-time WQM and environmental monitoring.

Preparation of amyloid N-terminal nonapeptide imprinted monolithic column and evaluation of adsorption properties

A novel β-amyloid protein capillary microextraction column was designed and prepared using epitope molecular imprinting technology for specific recognition of trace β-amyloid proteins in complex biological matrices. Using N-terminal nonapeptide of β-amyloid protein as template molecule, choline chloride-MAA and N-hydroxymethyl acrylamide as functional monomers, ethylene glycol dimethacrylate as crosslinker, the imprinted capillary monolithic column was prepared by thermal polymerization in the acetonitrile-water system. The optimal preparation parameters were obtained with the ratio of template: functional monomer: crosslinker at 1:6:16 (mmol/mmol/mmol). The physical property evaluation through Scanning electron microscopy, Fourier transform infrared spectroscopy analysis, zeta potential analysis, particle size analysis, and Brunauer-emmett-teller showed that a porous imprinted monolithic column with a high specific surface area was successfully prepared. The static adsorption experiment showed that the theoretical maximum adsorption capacity was 0.060 μg/column and the optimal imprinting factor was 2.27. Under the optimal extraction conditions, the imprinted column exhibited good template selectivity and excellent robustness. Finally, the extraction efficiency of the capillary imprinted column in actual plasma was evaluated using ELISA method. For Aβ 40 and Aβ 42, the detection limits were 1.00 pg/mL and 0.67 pg/mL, the quantification limits were 3.00 pg/mL and 2.00 pg/mL, the detection ranges were 7.5-120.0 pg/mL and 5.0-80.0 pg/mL, respectively. After extraction of plasma samples, the measured concentrations of Aβ 40 and Aβ 42 by imprinted column were 157.31 pg/mL and 48.22 pg/mL, respectively, which were significantly higher than the measured concentrations by non-imprinted column of 89.60 pg/mL and 41.02 pg/mL. In summary, the epitope imprinted capillary monolithic column prepared in this study can effectively enrich and separate trace amounts of amyloid proteins in complex samples, and is expected to provide a new sample pretreatment method for clinical detection of amyloid proteins.

Repackable microfluidic molecularly imprinted solid-phase extraction coupled with mass spectrometry (μMISPE-MS) for rapid analysis of mycotoxin in agri-foods: an example of zearalenone

Mycotoxins are detectable in 60-80% of food crops, posing significant threats to human health and food security, and causing substantial economic losses. Most mitigation approaches focus on detecting mycotoxins with standard methods based on liquid chromatography coupled with mass spectrometry (LC-MS). Typical MS methods require extensive sample preparation and clean-up due to the matrix effect, followed by time-consuming LC separation, complicating the analysis process and limiting analytical throughput. This study reports the development of a repackable microfluidic molecularly imprinted solid-phase extraction coupled with mass spectrometry (μMISPE-MS) method for rapid detection of zearalenone in agri-food samples. Silica microspheres coated with molecularly imprinted polymers were synthesized as the sorbent for analyte enrichment and sample clean-up. A cost-effective microfluidic chip was designed and fabricated as the μMISPE platform with fully automated operation, including on-line microcolumn packing and unpacking. With optimized solvent conditions and on-chip μMISPE protocol, the entire analytical process from sample to answer was completed within 15 min and achieved high recoveries (71-94%) for corn and rice samples at residue levels of 0.05-0.5 ppm (within Canadian regulatory limits of 0.2-10 ppm). This μMISPE-MS method provides a promising tool for improving mycotoxin monitoring in agri-food systems and is generalizable to other rapid analyses of targeted chemicals in complex matrices.

Molecular imprinted polymer-based potentiometric approach for the determination of carvedilol and ivabradine hydrochloride in dosage form, spiked human plasma and in presence of their oxidative degradates

Carivalan® pharmaceutical formulation, which includes carvedilol and ivabradine hydrochloride, is commonly prescribed for alleviating pain associated with angina. Solid contact ion-selective electrodes with wide range of applications have been developed for analysis of these two active ingredients. Those types of electrodes have common drawbacks. Aside from development of aqueous layer, the incorporated ion exchanger in plasticized membrane is usually unable to differentiate in sensing between two similarly charged lipophilic organic ions. These flaws impeded simultaneous quantification of carvedilol and ivabradine hydrochloride in their dosage form. First, attempts were made to stabilize possible signals by synthesizing hydrophobic multiwall carbon nanotubes-based carbon paste. Precipitation polymerization was used to create molecular imprinted polymers (MIPs) for each drug. MIPs' graved cavities serve as artificial host-tailored receptors that are able to recognize and bind to individual drugs. Carvedilol MIP-based sensor showed Nernstian slope of 55.30 mV/decade while the corresponding value for ivabradine one was 55.50 mV/decade. The respective LODs were 7.0 × 10- 8 M and 6.0 × 10- 7 M. Interference from excipients of pharmaceutical formulation, common plasma ions, and possible oxidation byproducts was not witnessed, permitting direct and simultaneous measurement of carvedilol and ivabradine in their tablet solution and spiked human plasma. Furthermore, the proposed technique was compared favorably with the official titrimetric and reported spectrophotometric methods for analyzing carvedilol and ivabradine, respectively.

Nanoimprinted Materials for Nanoparticle Sensing and Removal

The booming expansion of nanotechnology poses the problem of environmental pollution by nanoparticles (NPs). The available methods for sensing and removing NPs from the environment are typically lengthy and instrumentally demanding. The recent introduction of NP-imprinted polymers (NPIPs), either as films or bulk materials, is an important step toward the simple and fast sensing and removal of NPs from water and air. Similarly to the well-established molecularly imprinted polymers, in NPIPs, an organic or inorganic polymeric material is first obtained with embedded NPs. Then, the NPs are chemically or physically removed by acting as a template, i.e., leaving a polymeric matrix with cavities of the same shape and dimensions. After the first examples were published in 2014, the literature has so far reported an increasing number of NPIPs that are capable of reuptaking NPs from water (or, more rarely, air), with remarkable size and shape selectivity. By laying an NPIP layer on a reporter (typically an electrode), devices are obtained that are capable of sensing NPs. On the other hand, bulk NPIPs can reuptake massive amounts of NPs and have been used for the quantitative removal of NPs from water. This review begins with an overview of NP-imprinted hollow capsules, which can be considered the ancestors of NPIPs, both as conception and as preparative methods. Then, the literature on NPIPs is reviewed. Finally, the possible evolutions of NPIPs are highlighted from the perspective of stepping toward their real-life, field use.

Real-Time 5-Hydroxyindoleacetic Acid Monitoring in Guinea Pig Brain Using a Molecular Imprinted Polymer-Based Galvanic Redox Potentiometric Sensor

5-Hydroxyindoleacetic acid (5-HIAA), a vital metabolite of serotonin (5-HT), is crucial for understanding metabolic pathways and is implicated in various mental disorders. In situ monitoring of 5-HIAA is challenging due to the lack of affinity ligands and issues with electrochemical fouling. We present an advanced sensing approach that integrates customizable molecular imprinting polymer (MIP) with self-driven galvanic redox potentiometry (GRP) for precise, real-time in vivo monitoring of 5-HIAA. The sensor, featuring pyrrole as the functional monomer in the MIP on the micrometer-sized bipolar carbon fiber electrodes, exhibited nanomolar sensitivity and superior selectivity for 5-HIAA over biosynthetic pathway analogs like 5-hydroxytryptophan (5-HTP) and serotonin. The MIPGRP sensor demonstrated excellent reversibility and resistance to fouling, enabling continuous monitoring in live guinea pig brains. We observed that intraperitoneal 5-HTP injection increases brain 5-HIAA levels, which is amplified up to 8-fold with Carbidopa pretreatment, providing deeper insights into the serotonergic signaling pathway. This work underscores the MIPGRP sensor's potential as a versatile and reliable tool for advancing neuroscience research.

Molecularly Imprinted Nanozymes with Substrate Specificity: Current Strategies and Future Direction

Molecular imprinting technology (MIT) stands out for its exceptional simplicity and customization capabilities and has been widely employed in creating artificial antibodies that can precisely recognize and efficiently capture target molecules. Concurrently, nanozymes have emerged as promising enzyme mimics in the biomedical field, characterized by their remarkable stability, ease of production scalability, robust catalytic activity, and high tunability. Drawing inspiration from natural enzymes, molecularly imprinted nanozymes combine the unique benefits of both MIT and nanozymes, thereby conferring biomimetic catalysts with substrate specificity and catalytic selectivity. In this review, the latest strategies for the fabrication of molecularly imprinted nanozymes, focusing on the use of organic polymers and inorganic nanomaterials are explored. Additionally, cutting-edge techniques for generating atom-layer-imprinted islands with ultra-thin atomic-scale thickness is summarized. Their applications are particularly noteworthy in the fields of catalyst optimization, detection techniques, and therapeutic strategies, where they boost reaction selectivity and efficiency, enable precise identification and quantification of target substances, and enhance therapeutic effectiveness while minimizing adverse effects. Lastly, the prevailing challenges in the field and delineate potential avenues for future progress is encapsulated. This review will foster advancements in artificial enzyme technology and expand its applications.

Emerging Combination of Hydrogel and Electrochemical Biosensors

Electrochemical sensors are among the most promising technologies for biomarker research, with outstanding sensitivity, selectivity, and rapid response capabilities that make them important in medical diagnostics and prognosis. Recently, hydrogels have gained attention in the domain of electrochemical biosensors because of their superior biocompatibility, excellent adhesion, and ability to form conformal contact with diverse surfaces. These features provide distinct advantages, particularly in the advancement of wearable biosensors. This review examines the contemporary utilization of hydrogels in electrochemical sensing, explores strategies for optimization and prospective development trajectories, and highlights their distinctive advantages. The objective is to provide an exhaustive overview of the foundational principles of electrochemical sensing systems, analyze the compatibility of hydrogel properties with electrochemical methodologies, and propose potential healthcare applications to further illustrate their applicability. Despite significant advances in the development of hydrogel-based electrochemical biosensors, challenges persist, such as improving material fatigue resistance, interfacial adhesion, and maintaining balanced water content across various environments. Overall, hydrogels have immense potential in flexible biosensors and provide exciting opportunities. However, resolving the current obstacles will necessitate additional research and development efforts.

Deep purification of perfluorinated electronic specialty gas with a scalable metal-organic framework featuring tailored positive potential traps

The sequestration of trace hexafluoropropylene (C3F6) is a critical yet formidable task in the production of high-purity perfluoropropane (C3F8), an important perfluorinated electronic specialty gas (F-gas) in the advanced electronics industry. Traditional adsorbents struggle with uneven, low-pressure uptake and compromises in selectivity. This work utilizes aperture size-electrostatic potential matching within a robust metal-organic framework (Al-PMA) to facilitate selective, reversible binding of C3F6 while excluding larger C3F8 molecules. The presence of bridging hydroxyl groups (μ2-OH) in Al-PMA creates positive electrostatic potential traps that securely anchor C3F6 through strong hydrogen bonding, evidenced by in-situ infrared and 19F magic angle spinning nuclear magnetic resonance spectroscopy. Breakthrough experiments demonstrate the efficient removal of trace C3F6 from C3F8 under ambient conditions, achieving C3F8 purity exceeding 99.999%. The scalability of Al-PMA synthesis, remarkable stability, and exceptional performance highlight its potential as a promising adsorbent for industrial C3F6/C3F8 separations.

Molecularly imprinted hydrogels embedded with two-dimensional photonic crystals for the detection of dexamethasone/betamethasone sodium phosphate

Dexamethasone sodium phosphate (DSP) and betamethasone sodium phosphate (BSP) imprinted hydrogels embedded with two-dimensional photonic crystals (2DPC) were developed as hormones-sensitive photonic hydrogel sensors with highly sensitive, selective, anti-interference and reproducible recognition capability. The DSP/BSP molecularly imprinted photonic hydrogels (denoted as DSP-MIPH and BSP-MIPH) can specifically recognize DSP/BSP by rebinding the DSP/BET molecules to nanocavities in the hydrogel network. This recognition is enabled by the similar shape, size, and binding sites of the nanocavities to the target molecules. The rebinding of hormones molecules causes the hydrogel to swell, resulting in a particle spacing increase of the embedded 2DPC of the hydrogel. The particle spacing increase can be used as sensing signal and can be acquired by simply measuring the Debye diffraction diameters of the photonic hydrogel sensor before and after exposure with a laser pointer and a ruler. The particle spacing increments of the DSP-MIPH and BSP-MIPH sensors linearly change when DSP and BSP concentrations changes within the ranges 0.025-1 μM, 10-100 μM, and 100-500 μM, and the limits of detection (LoD) are 21.8 nM for DSP and 12.6 nM for BSP, respectively. These photonic hydrogel sensors were successfully applied to the determination of DSP/BSP contents in the real pharmaceutical injections, providing an ideal strategy for the development of portable hormones sensors.

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

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

A Photolockable Polyaromatic Capsule Designed via Regiochemical Substitution

Photocontrol over host frameworks is an elegant way to manipulate host-guest composites, yet the majority of previous systems suffer from long irradiation time and narrow guest scope, and are restricted to intramolecular photoreactions in organic solvents. Herein we present a photolockable polyaromatic capsule with high guest binding abilities in water. The capsule assembles from bent amphiphiles featuring two 2-subsutituted anthracene panels, which shows high stability against dilution and undergoes intermolecular [4+4] photo-oligomerization upon short light irradiation (<10 min). The photolocked capsule provides a roughly spherical framework, with an average, core diameter of ~3 nm, composed of amphiphilic oligomers (e. g., trimer). The new capsule shows improved host ability (up to 10-fold) in water toward various hydrophobic compounds (e. g., organic and metal-complex dyes), as compared with an analogous, non-photolockable capsule with 9-subsutituted anthracene panels. In addition, the resultant dye-loaded capsules are also successfully photolocked via short irradiation with high retention of the bound dyes.

A Novel Molecularly Imprinted Electrochemiluminescence Sensor Based on Mxene Quantum Dots for Selective Detection of Oseltamivir in Biological Samples

Oseltamivir is a drug that has been widely used to prevent and treat influenza A and B. In this work, an ultrasensitive, simple, and novel electrochemiluminescence (ECL) sensor combined with molecularly imprinted polymers (MIP-ECL) based on a graphene-like two-dimensional material, Mxene quantum dots (MQDs) was constructed to selectively detect oseltamivir. A molecularly imprinted polymer membrane containing an oseltamivir template was constructed by electropolymerization and elution of modified MQDs on a glassy carbon electrode. Under optimized experimental conditions, the MIP-ECL sensor could detect oseltamivir in the range of 10-10 to 10-6 M (R2 = 0.9816), with a low limit of detection of 6.5 × 10-11 M (S/N = 3), and the recovery rates of oseltamivir in biological samples were 92.21-104.2%, with relative standard deviations of 3.70%~5.70%. The developed MIP-ECL sensor provides a new idea for detecting oseltamivir, which was successfully applied to the determination of oseltamivir in serum samples, indicating great potential for application in clinical diagnostics.

Deep eutectic solvent-based magnetic molecular nanomaterials coupled with fluorescent carbon dots as a new strategy to highly enrich and sensitively detect doxycycline in food matrices

The highly selective enrichment and sensitive detection of antibiotics in food are crucial for human health, environmental monitoring, and management. In this study, deep eutectic solvents (DESs) were used as eco-friendly functional monomers, a magnetic molecular nanomaterial (DES-MMIP) coupled with carbon dots (CDs) was developed as a sensitive fluorescent probe for the selective enrichment and detection of trace amounts of doxycycline (DOX). Under optimal conditions, the method exhibited good linearity within 0.5-50 μg·L-1, a low detection limit of 0.34 nM for DOX detection. Furthermore, the DES-MMIP displayed excellent reusability and storage stability. With responsive, excellent selectivity and an eco-friendly nature, the established method is successful in detecting DOX in food matrices, with an average spiked recovery of 87.5 %-97.8 %. This strategy of integrating CDs and DES-MMIP for DOX detection conforms to the green concept of environmental protection and provides a new material and research approach for efficient analysis of DOX in complex matrices.

Selective apigenin assay in plant extracts and herbal supplement with molecularly imprinted polymer-based electrochemical sensor

This study is the first successful application of a nanomaterial-supported molecularly imprinted polymer (MIP)-based electrochemical sensor for the sensitive and selective determination of apigenin (API), which is a naturally occurring product of the flavone class that is an aglycone of several glycosides. Secondary metabolites are biologically active substances produced by plants in response to various environmental factors. The levels of these compounds can vary depending on factors such as climate, soil conditions and the season in which the plants are grown. Therefore, the analysis of these compounds is essential to properly understand the biological effects of plant extracts and to ensure their safe use. To increase the glassy carbon electrode (GCE) surface's active surface area and porosity, zinc oxide nanoparticles (ZnO NPs) were integrated into the MIP-based electrochemical sensor design. Tryptophan methacrylate (TrpMA) was selected as the functional monomer along with other MIP components such as 2-hydroxyethyl methacrylate (HEMA, basic monomer), 2-hydroxy-2-methylpropiophenone (initiator), and ethylene glycol dimethacrylate (EGDMA, crosslinking agent). The morphological and electrochemical characterizations of the developed API/ZnO NPs/TrpMA@MIP-GCE sensor were performed with scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The indirect measurement approach via 5.0 mM [Fe(CN)6]3-/4- solution was utilized to determine API in the linear range of 1.0x10-13 M - 1.0x10-12 M. The limit of detection (LOD) and limit of quantification (LOQ) for standard solutions were found to be 2.47x10-14 and 8.23x10-14 M, respectively. In addition, the extraction processes were carried out using ultrasound-assisted extraction (UAE) and maceration (MCR) procedures. For Apium graveolens L., Petroselinum crispum (Mill.) Fuss and herbal supplement, the API recoveries varied from 98.79 % to 102.71 %, with average relative standard deviations (RSD) less than 2.25 % in all three cases. The sensor's successful performance in the presence of components with chemical structures similar to the API was also demonstrated, revealing its unique selectivity.

Design of a molecularly imprinted polymer sensor modified with saffron-based copper nanoflowers for highly selective and sensitive determination of bortezomib

This work represents the first successful application of a molecularly imprinted polymer (MIP)-based electrochemical sensor for the sensitive and selective determination of the first developed proteasome inhibitor, bortezomib (BOR). BOR is used for the treatment of multiple myeloma, gastrointestinal stromal tumors, and mantle cell lymphoma. It shows its desired effect through the boronate group and can be administered intravenously or subcutaneously. The MIP-based electrochemical sensor design includes the integration of green-synthesized saffron-based copper nanoflowers (CuNFs) from Crocus sativus L. to increase the active surface area and porosity of the glassy carbon electrode (GCE) surface. 2-Acrylamido-2-methyl-1-propanesulfonic acid (AMPS) was selected as the functional monomer along with other MIP components. Detailed characterizations of the developed CuNFs/AMPS/MIP-GCE sensor and CuNFs were performed using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray analysis (EDX), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The indirect measurement approach using 5.0 mM [Fe(CN)6]3-/4- solution was used to determine BOR in the linear range of 2.5 × 10-13 M - 2.5 × 10-12 M (0.25-2.5 pM). The LOD and LOQ values of the sensor obtained at the fM level (29 fM and 96.7 fM), which has a linear response in the commercial human serum sample in the same concentration range, emphasize its sensitivity (1.89 × 1013 and 2.14 × 1013 μA/M for standard solution and serum). The repeatability and reproducibility of the sensor were between 0.87 % and 2.17 %, showing its reliability. The successful performance of the sensor in the presence of metabolites belonging to BOR demonstrates its unique selectivity. The selectivity was demonstrated via relative imprinting factor (IF') values (higher than 3.5) against BOR's metabolites. The stability of the CuNFs/AMPS/MIP-GCE sensor was found to be 5 days.

A Molecularly Imprinted Electrochemical Sensor for Carbendazim Detection Based on Synergy Amplified Effect of Bioelectrocatalysis and Nanocomposites

The highly selective and sensitive determination of pesticide residues in food is critical for human health protection. Herein, the specific selectivity of molecularly imprinted polymers (MIPs) was proposed to construct an electrochemical sensor for the detection of carbendazim (CBD), one of the famous broad-spectrum fungicides, by combining with the synergistic effect of bioelectrocatalysis and nanocomposites. Gold nanoparticle-reduced graphene oxide (AuNP-rGO) composites were electrodeposited on a polished glassy carbon electrode (GCE). Then the MIP films were electropolymerized on the surface of the nanolayer using CBD as the template molecule and o-phenylenediamine (OPD) as the monomer. The detection sensitivity of CBD on the heterogeneous structure films was greatly amplified by AuNP-rGO composites and the bioelectrochemical oxidation of glucose, which was catalyzed by glucose oxidase (GOD) with the help of mediator in the underlying solution. The developed sensor showed high selectivity, good reproducibility, and excellent stability towards CBD with the linear range from 2.0 × 10-9 to 7.0 × 10-5 M, and the limit of detection (LOD) of 0.68 nM (S/N = 3). The expected system would provide a new idea for the development of simple and sensitive molecularly imprinted electrochemical sensors (MIESs).

Wearable Electrochemical Biosensors for Advanced Healthcare Monitoring

Recent advancements in wearable electrochemical biosensors have opened new avenues for on-body and continuous detection of biomarkers, enabling personalized, real-time, and preventive healthcare. While glucose monitoring has set a precedent for wearable biosensors, the field is rapidly expanding to include a wider range of analytes crucial for disease diagnosis, treatment, and management. In this review, recent key innovations are examined in the design and manufacturing underpinning these biosensing platforms including biorecognition elements, signal transduction methods, electrode and substrate materials, and fabrication techniques. The applications of these biosensors are then highlighted in detecting a variety of biochemical markers, such as small molecules, hormones, drugs, and macromolecules, in biofluids including interstitial fluid, sweat, wound exudate, saliva, and tears. Additionally, the review also covers recent advances in wearable electrochemical biosensing platforms, such as multi-sensory integration, closed-loop control, and power supply. Furthermore, the challenges associated with critical issues are discussed, such as biocompatibility, biofouling, and sensor degradation, and the opportunities in materials science, nanotechnology, and artificial intelligence to overcome these limitations.

Uniform Polymer Microspheres by Photoinduced Metal-Free Atom Transfer Radical Precipitation Polymerization

Herein, a photoinduced method is introduced for the synthesis of highly cross-linked and uniform polymer microspheres by atom transfer radical polymerization (ATRP) at room temperature and in the absence of stabilizers or surfactants. Uniform particles are obtained at monomer concentrations as high as 10% (by volume), with polymers being exempt from contamination by residual transition metal catalysts, thereby overcoming the two major longstanding problems associated with thermally initiated ATRP-mediated precipitation polymerization. Moreover, the obtained particles have also immobilized ATRP initiators on their surface, which directly enables the controlled growth of densely grafted polymer layers with adjustable thickness and a well-defined chemical composition. The method is then employed successfully for the synthesis of molecularly imprinted polymer microspheres.

Single-Walled Carbon Nanotubes as Optical Transducers for Nanobiosensors In Vivo

Semiconducting single-walled carbon nanotubes (SWCNTs) may serve as signal transducers for nanobiosensors. Recent studies have developed innovative methods of engineering molecularly specific sensors, while others have devised methods of deploying such sensors within live animals and plants. These advances may potentiate the use of implantable, noninvasive biosensors for continuous drug, disease, and contaminant monitoring based on the optical properties of single-walled carbon nanotubes (SWCNTs). Such tools have substantial potential to improve disease diagnostics, prognosis, drug safety, therapeutic response, and patient compliance. Outside of clinical applications, such sensors also have substantial potential in environmental monitoring or as research tools in the lab. However, substantial work remains to be done to realize these goals through further advances in materials science and engineering. Here, we review the current landscape of quantitative SWCNT-based optical biosensors that have been deployed in living plants and animals. Specifically, we focused this review on methods that have been developed to deploy SWCNT-based sensors in vivo as well as analytes that have been detected by SWCNTs in vivo. Finally, we evaluated potential future directions to take advantage of the promise outlined here toward field-deployable or implantable use in patients.