High-performance fentanyl molecularly imprinted electrochemical sensing platform designed through molecular simulations.

BACKGROUND: Fentanyl and its derivatives are a type of potent opioid analgesics, with the characteristics of diverse structure, high toxicity, extremely low content, and high fatality rate. Currently, they have become one of the most serious problems in international drug abuse control due to their extensive use in drug production and use. Therefore, the development of a rapid, sensitive, and accurate method for detecting trace fentanyl is of great significance. In this study, in view of its complex structure and trace concentration, a new molecular imprinting electrochemical sensor was developed through molecular simulations followed by experimental validation to detect trace fentanyl. RESULTS: The process consisted of first obtaining the optimal functional monomer and its molar ratio through molecular simulations. The recognition sites of fentanyl-imprinted polymers were predicted to guide the synthesis of imprinted membranes with precision approach to ensure an efficient and accurate reaction process. Reduced graphene oxide (ErGO) was then deposited on glassy carbon electrode surface by electrochemical reduction to yield large numbers of active sites suitable for catalyzing reactions of fentanyl piperidine for promoted efficient electron transfer and amplified sensitivity of the sensor. Accordingly, fentanyl molecularly imprinted film was formed through one-step electropolymerization to yield greatly improved sensing selectivity due to the specific recognition of molecularly imprinted polymer. Under optimal experimental conditions, the fentanyl sensor showed an extended detection range of 3.84 × 10-9 mol L-1-1.72 × 10-6 mol L-1 and a detection limit of 1.28 × 10-9 mol L-1. SIGNIFICANCE: A distinctive feature of this sensor is its molecularly imprinted polymerized membrane, which offers excellent specific recognition, thereby boosting the sensor's selectivity. Throughout the sensor's development process, molecular simulations were employed to steer the synthesis of molecularly imprinted polymers and predict the recognition sites of fentanyl-imprinted polymers. The experimental outcomes proved to align with the simulation data. The final sensor exhibited outstanding selectivity, repeatability, stability, and high sensitivity. The sensor was effectively used to reliably track fentanyl in human serum samples, with acceptable analytical reliability, suggesting its potential for practical applications.

Development of a "turn off" fluorescent molecularly imprinted nanoparticle-based sensor for selective captopril quantification in synthetic urine and wastewater samples.

The combination of silica nanoparticles with fluorescent molecularly imprinted polymers (Si-FMIPs) prepared by a one-pot sol-gel synthesis method to act as chemical sensors for the selective and sensitive determination of captopril is described. Several analytical parameters were optimized, including reagent ratio, solvent, concentration of Si-FMIP solutions, and contact time. Fourier-transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), and the ninhydrin assay were used for characterization. The selectivity was evaluated against molecules belonging to other drug classes, such as fluoroquinolones, nonacid nonopioids, benzothiadiazine, alpha amino acids, and nitroimidazoles. Under optimized conditions, the Si-FMIP-based sensor exhibited a working range of 1-15 µM, with a limit of detection (LOD) of 0.7 µM, repeatability of 6.4% (n = 10), and suitable recovery values at three concentration levels (98.5% (1.5 µM), 99.9% (3.5 µM), and 99.2% (7.5 µM)) for wastewater samples. The sensor provided a working range of 0.5-15 µM for synthetic urine samples, with an LOD of 0.4 µM and a repeatability of 7.4% (n = 10) and recovery values of 93.7%, 92.9%, and 98.0% for 1.0 µM, 3.5 µM, and 10 µM, respectively. In conclusion, our single-vessel synthesis approach for Si-FMIPs proved to be highly effective for the selective determination of captopril in wastewater and synthetic urine samples.

Development of a simple polymer-based sensor for detection of the Pirimicarb pesticide.

In this study, a sensitive and selective fluorescent chemosensor was developed for the determination of pirimicarb pesticide by adopting the surface molecular imprinting approach. The magnetic molecularly imprinted polymer (MIP) nanocomposite was prepared using pirimicarb as the template molecule, CuFe2O4 nanoparticles, and graphene quantum dots as a fluorophore (MIP-CuFe2O4/GQDs). It was then characterized using X-ray diffraction (XRD) technique, Fourier transforms infrared (FT-IR) spectroscopy, scanning electron microscope (SEM), and transmission electron microscopy (TEM). The response surface methodology (RSM) was also employed to optimize and estimate the effective parameters of pirimicarb adsorption by this polymer. According to the experimental results, the average particle size and imprinting factor (IF) of this polymer are 53.61 nm and 2.48, respectively. Moreover, this polymer has an excellent ability to adsorb pirimicarb with a removal percentage of 99.92 at pH = 7.54, initial pirimicarb concentration = 10.17 mg/L, polymer dosage = 840 mg/L, and contact time = 6.15 min. The detection of pirimicarb was performed by fluorescence spectroscopy at a concentration range of 0-50 mg/L, and a sensitivity of 15.808 a.u/mg and a limit of detection of 1.79 mg/L were obtained. Real samples with RSD less than 2 were measured using this chemosensor. Besides, the proposed chemosensor demonstrated remarkable selectivity by checking some other insecticides with similar and different molecular structures to pirimicarb, such as diazinon, deltamethrin, and chlorpyrifos.

Combination of core-shell structured NH2-UiO-66@ZIF-8 loaded Ru (bpy)3 2+ and molecularly imprinted copolymer for the sensitive ECL detection of tetracycline.

A molecularly imprinted electrochemiluminescent sensor is developed for the sensitive detection of tetracycline in environmental and food samples. The sensor uses an ionic liquid (i.e. [APMIM]Br) modified graphene-carbon nanotube composite (GMI) material as substrate, a double-layered core-shell metal-organic framework NH2-UiO-66@ZIF-8 (NUZ) loaded bipyridyl ruthenium (NUZ@Ru) as luminescent material, and a molecularly imprinted copolymer of o-phenylenediamine and hydroquinone as recognition element. The ionic liquid-modified graphene-carbon nanotube composite has a favorable three-dimensional structure, high specific surface area, and good hydrophilicity; the core-shell structured metal-organic framework has high stability and plentiful reaction sites for loading; the molecularly imprinted copolymer film has enhanced stability and recognition effect. Hence, the resulting sensor combines the merits of several materials and presents improved performance. Under the optimum detection conditions, it shows a wide linear range of 0.05 µM - 1 mM, a low detection limit of 20 nM, high selectivity, and excellent stability. It has been successfully applied to the detection of tetracycline in different samples.

A new three-dimensional (3D) molecularly imprinted polymer fluoroprobe based on green-red dual-emission signals of carbon quantum dots and self-polymerization of dopamine (CDs@PDA-MIPs) for sensitive detection of nifedipine.

Nifedipine (NIF), as one of the dihydropyridine calcium channel blockers, is widely used in the treatment of hypertension. However, misuse or ingestion of NIF can result in serious health issues such as myocardial infarction, arrhythmia, stroke, and even death. It is essential to design a reliable and sensitive detection method to monitor NIF. In this work, an innovative molecularly imprinted polymer dual-emission fluorescent sensor (CDs@PDA-MIPs) strategy was successfully designed for sensitive detection of NIF. The fluorescent intensity of the probe decreased with increasing NIF concentration, showing a satisfactory linear relationship within the range 1.0 × 10-6 M ~ 5.0 × 10-3 M. The LOD of NIF was 9.38 × 10-7 M (S/N = 3) in fluorescence detection. The application of the CDs@PDA-MIPs in actual samples such as urine and Qiangli Dingxuan tablets has been verified, with recovery ranging from 97.8 to 102.8% for NIF. Therefore, the fluorescent probe demonstrates great potential as a sensing system for detecting NIF.

Bilateral efforts to improve SERS detection efficiency of exosomes by Au/Na7PMo11O39 Combined with Phospholipid Epitope Imprinting.

Detection of cancer-related exosomes in body fluids has become a revolutionary strategy for early cancer diagnosis and prognosis prediction. We have developed a two-step targeting detection method, termed PS-MIPs-NELISA SERS, for rapid and highly sensitive exosomes detection. In the first step, a phospholipid polar site imprinting strategy was employed using magnetic PS-MIPs (phospholipids-molecularly imprinted polymers) to selectively isolate and enrich all exosomes from urine samples. In the second step, a nanozyme-linked immunosorbent assay (NELISA) technique was utilized. We constructed Au/Na7PMo11O39 nanoparticles (NPs) with both surface-enhanced Raman scattering (SERS) property and peroxidase catalytic activity, followed by the immobilization of CD9 antibodies on the surface of Au/Na7PMo11O39 NPs. The Au/Na7PMo11O39-CD9 antibody complexes were then used to recognize CD9 proteins on the surface of exosomes enriched by magnetic PS-MIPs. Lastly, the high sensitivity detection of exosomes was achieved indirectly via the SERS activity and peroxidase-like activity of Au/Na7PMo11O39 NPs. The quantity of exosomes in urine samples from pancreatic cancer patients obtained by the PS-MIPs-NELISA SERS technique showed a linear relationship with the SERS intensity in the range of 6.21 × 107-2.81 × 108 particles/mL, with a limit of detection (LOD) of 5.82 × 107 particles/mL. The SERS signal intensity of exosomes in urine samples from pancreatic cancer patients was higher than that of healthy volunteers. This bidirectional MIPs-NELISA-SERS approach enables noninvasive, highly sensitive, and rapid detection of cancer, facilitating the monitoring of disease progression during treatment and opening up a new avenue for rapid early cancer screening.

Needle-in-needle electrochemical sensor for in-vivo monitoring of anticancer drug etoposide.

Therapeutic drug monitoring (TDM) serves as a potent tool for adjusting drug concentration within a reasonable range. However, continuous monitoring of anticancer drugs in-vivo presents a significant challenge. Herein, we propose a needle-in-needle electrochemical sensor based on an acupuncture needle electrode, capable of monitoring the anticancer drug etoposide in the peritoneal cavity of living rats. The acupuncture needle was modified with Au nanoparticles and etoposide-templated molecularly imprinted polymer (MIP), resulting in high sensitivity and selectivity in the electrochemical detection of etoposide. The modified acupuncture needle (0.16 mm diameter) was anchored inside a syringe needle (1.40 mm diameter), allowing the outer syringe needle to protect the modified materials of the inner acupuncture needle during skin piercing. Due to the unique needle-in-needle design, high stability was obtained during in-vivo etoposide monitoring. Connecting to a smartphone-controlled portable electrochemical workstation, the needle-in-needle sensor offers great convenience in point-of-care TDM. Moreover, the electrode materials on the acupuncture needle were carefully characterized and optimized. Under the optimized conditions, low detection limits and wide linear range were achieved. This work provides new insights into acupuncture needle electrochemical sensors and further expands the feasibility for real-time and in-vivo detection.

An Innovative Approach for Tailoring Molecularly Imprinted Polymers for Biosensors-Application to Cancer Antigen 15-3.

This work presents a novel approach for tailoring molecularly imprinted polymers (MIPs) with a preliminary stage of atom transfer radical polymerization (ATRP), for a more precise definition of the imprinted cavity. A well-defined copolymer of acrylamide and N,N'-methylenebisacrylamide (PAAm-co-PMBAm) was synthesized by ATRP and applied to gold electrodes with the template, followed by a crosslinking reaction. The template was removed from the polymer matrix by enzymatic/chemical action. The surface modifications were monitored via electrochemical impedance spectroscopy (EIS), having the MIP polymer as a non-conducting film designed with affinity sites for CA15-3. The resulting biosensor exhibited a linear response to CA15-3 log concentrations from 0.001 to 100 U/mL in PBS or in diluted fetal bovine serum (1000×) in PBS. Compared to the polyacrylamide (PAAm) MIP from conventional free-radical polymerization, the ATRP-based MIP extended the biosensor's dynamic linear range 10-fold, improving low concentration detection, and enhanced the signal reproducibility across units. The biosensor demonstrated good sensitivity and selectivity. Overall, the work described confirmed that the process of radical polymerization to build an MIP material influences the detection capacity for the target substance and the reproducibility among different biosensor units. Extending this approach to other cancer biomarkers, the methodology presented could open doors to a new generation of MIP-based biosensors for point-of-care disease diagnosis.

Unlocking New Avenues: Solid-State Synthesis of Molecularly Imprinted Polymers.

Molecularly imprinted polymers (MIPs) are established artificial molecular recognition platforms with tailored selectivity towards a target molecule, whose synthesis and functionality are highly influenced by the nature of the solvent employed in their synthesis. Steps towards the "greenification" of molecular imprinting technology (MIT) has already been initiated by the elaboration of green MIT principles; developing MIPs in a solvent-free environment may not only offer an eco-friendly alternative, but could also significantly influence the affinity and expected selectivity of the resulting binding sites. In the current study the first solvent-free mechanochemical synthesis of MIPs via liquid-assisted grinding (LAG) is reported. The successful synthesis of the imprinted polymer was functionally demonstrated by measuring its template rebinding capacity and the selectivity of the molecular recognition process in comparison with the ones obtained by the conventional, non-covalent molecular imprinting process in liquid media. The results demonstrated similar binding capacities towards the template molecule and superior chemoselectivity compared to the solution-based MIP synthesis method. The adoption of green chemistry principles with all their inherent advantages in the synthesis of MIPs may not only be able to alleviate the potential environmental and health concerns associated with their analytical (e.g., selective adsorbents) and biomedical (e.g., drug carriers or reservoirs) applications, but might also offer a conceptual change in molecular imprinting technology.

Ultrasensitive detection of chlortetracycline in animal-origin food using molecularly imprinted electrochemical sensor based on SnS2/ZnCo-MOF and AuNPs.

The chlortetracycline (CTC) residue in food poses a threat to human health. Therefore, developing sensitive, convenient and selective analytical methods for CTC detection is crucial. This study innovatively uses tin disulfide/bimetallic organic framework (SnS2/ZnCo-MOF) nanocomposites in conjunction with gold nanoparticles (AuNPs) to co-modify a glassy carbon electrode (GCE). Further, a molecularly imprinted polymer (MIP)-based electrochemical sensing platform Au-MIP/SnS2/ZnCo-MOF/Au/GCE (AZG) was fabricated for selective CTC detection. SnS2/ZnCo-MOF enhanced the stability and surface area of the AZG sensor. The presence of AuNPs facilitated electron transport between the probe and the electrode across the insulating MIP layer. The fixation of AuNPs and MIP via electropolymerization enhanced the selective recognition of this sensor and amplified its output signal. The AZG sensor demonstrated a wide linear detection range (0.1-100 µM), low detection limit (0.072 nM), and high sensitivity (0.830 µA µM-1). It has been used for detecting CTC in animal-origin food with good recovery (96.08%-104.60%).

Conjugated molecularly imprinted polymers based on covalent organic frameworks: Fluorescent sensing platform for specific capture of urea and elimination of ethyl carbamate.

This study described the preparation of an azide covalent organic framework-embedded molecularly imprinted polymers (COFs(azide)@MIPs) platform for urea adsorption and indirect ethyl carbamate (EC) removal from Chinese yellow rice wine (Huangjiu). By modifying the pore surface of COFs using the copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction, COFs(azide) with a high fluorescence quantum yield and particular recognition ability were inventively produced. In order to selectively trap urea, the COFs(azide) were encased in an imprinted shell layer via imprinting technology. With a detection limit (LOD) of 0.016 µg L-1 (R2 = 0.9874), the COFs(azides)@MIPs demonstrated a good linear relationship with urea in the linear range of 0-5 µg L-1. Using real Huangjiu samples, the spiking recovery trials showed the viability of this sensing platform with recoveries ranging from 88.44 % to 109.26 % and an RSD of less than 3.40 %. The Huangjiu processing model system achieved 38.93 % EC reduction by COFs(azides)@MIPs. This research will open up new avenues for the treatment of health problems associated with fermented alcoholic beverages, particularly Huangjiu, while also capturing and removing hazards coming from food.

An electrochemical sensor based on molecularly imprinted poly(o-phenylenediamine) for the detection of thymol.

A molecularly imprinted electrochemical sensor was facilely fabricated for the detection of thymol (THY). o-Phenylenediamine (oPD) was used as the functional monomer and electropolymerized on the surface of the glassy carbon electrode (GCE) by using THY as the templates. After the THY templates were removed with 50 % (v/v) ethanol, imprinted cavities complementary to the templates were formed within the poly(o-phenylenediamine) (PoPD) films. The resultant molecularly imprinted PoPD/GCE (MI-PoPD/GCE) was used for the detection of THY, and a wide linear range from 0.5 to 100 µM with a low limit of detection (LOD) of 0.084 µM were obtained under the optimal conditions. The developed MI-PoPD/GCE also displays high selectivity, reproducibility and stability for THY detection. Finally, the content of THY in the real samples was accurately determined by the as-fabricated MI-PoPD/GCE, demonstrating its high practicability and reliability.

Computational design and preparation of water-compatible noncovalent imprinted microspheres.

Herein, 2,4-dichlorophenoxyacetic acid (2,4-D) was used as a model template in a rational design strategy to produce water-compatible noncovalent imprinted microspheres. The proposed approach involved computational modelling for screening functional monomers and a simple method for preparing monodisperse and highly cross-linked microspheres. The fabricated non-imprinted polymer (NIP) and 2,4-d-imprinted polymer (2,4-d-MIP) were characterised, and their adsorption capabilities in an aqueous environment were evaluated. Results reveal that the pseudo-second-order kinetics model was appropriate for representing the adsorption of 2,4-D on NIP and 2,4-d-MIP, with R2 values of 0.97 and 0.99, respectively. The amount of 2,4-D adsorbed on 2,4-d-MIP (97.75 mg g-1) was considerably higher than those of phenoxyacetic acid (35.77 mg g-1), chlorogenic acid (9.72 mg g-1), spiramycin (1.56 mg g-1) and tylosin (1.67 mg g-1). Furthermore, it exhibited strong resistance to protein adsorption in an aqueous medium. These findings confirmed the feasibility of the proposed approach, providing a reference for the development of water-compatible noncovalent imprinted polymers.

Plant-based zinc nanoflowers assisted molecularly imprinted polymer for the design of an electrochemical sensor for selective determination of abrocitinib.

The first electrochemical sensor application in the literature is described for the sensitive and selective determination of the selective Janus kinase (JAK)-1 inhibitor abrocitinib (ABR). ABR is approved by the U.S. Food and Drug Administration (FDA) for the treatment of atopic dermatitis. The molecularly imprinted polymer (MIP)-based sensor was designed to incorporate zinc nanoflower (ZnNFs)-graphene oxide (GO) conjugate (ZnNFs@GO), synthesized from the root methanolic extract (RME) of the species Alkanna cappadocica Boiss. et Bal. to improve the porosity and effective surface area of the glassy carbon electrode (GCE). Furthermore, the MIP structure was prepared using ABR as a template molecule, 4-aminobenzoic acid (4-ABA) as a functional monomer, and other additional components. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) were used to characterize the surface and structure of the synthesized nanomaterial and MIP-based surface. Among the electrochemical methods, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were preferred for detailed electrochemical characterization, and differential pulse voltammetry (DPV) was preferred for all other electrochemical measurements using 5.0 mM [Fe(CN)6]3-/4- solution as the redox probe. The MIP-based sensor, which was the result of a detailed optimization phase, gave a linear response in the 1.0 × 10-13 - 1.0 × 10-12 M range in standard solution and serum sample. The obtained limit of detection (LOD) and limit of quantification (LOQ) values and recovery studies demonstrated the sensitivity, accuracy, and applicability of the sensor. Selectivity, the most important feature of the MIP-based sensor, was verified by imprinting factor calculations using ibrutinib, ruxolitinib, tofacitinib, zonisamide, and acetazolamide.

Molecularly Imprinted Drug Carrier for Lamotrigine-Design, Synthesis, and Characterization of Physicochemical Parameters.

This study presents the initial attempt at introducing a magnetic molecularly imprinted polymer (MIP) designed specifically for lamotrigine with the purpose of functioning as a drug carrier. First, the composition of the magnetic polymer underwent optimization based on bulk polymer adsorption studies and theoretical analyses. The magnetic MIP was synthesized from itaconic acid and ethylene glycol dimethacrylate exhibiting a drug loading capacity of 3.4 ± 0.9 µg g-1. Structural characterization was performed using powder X-ray diffraction analysis, vibrating sample magnetometry, and Fourier transform infrared spectroscopy. The resulting MIP demonstrated controlled drug released characteristics without a burst effect in the phospahe buffer saline at pH 5 and 8. These findings hold promise for the potential nasal administration of lamotrigine in future applications.

Polymeric membrane potentiometric sensors based on template-removal-free imprinted receptors for determination of antibiotics.

Currently, Nernstian-response-based polymeric membrane potentiometric sensors using molecularly imprinted polymers (MIPs) as receptors have been successfully developed for determination of organic ionic species. However, the preparation of these MIP receptors usually involves tedious and time-consuming template-removal procedures. Herein, a template-removal-free MIP is proposed and used as a receptor for fabrication of a potentiometric sensor. The proposed methodology not only significantly shortens the preparation time of MIP-based potentiometric sensors but also improves the batch-to-batch reproducibility of these sensors. By using antibiotic vancomycin as a model, the new concept offers a linear concentration range of 1.0 × 10-7 to 1.0 × 10-4 mol L-1 with a detection limit of 2.51 × 10-8 mol L-1. It can be expected that the template-removal-free MIP-based sensing strategy could lay the foundation for simple fabrication of electrochemical sensors without the need for template removal such as potentiometric and capacitive sensors and ion-sensitive field-effect transistors.

A novel electrochemical sensor based on a Cu-coordinated molecularly imprinted polymer and MoS2 modified chitin-derived carbon for selective detection of dextromethorphan.

Dextromethorphan (DXM) is a widely utilized central antitussive agent, which is frequently abused by individuals seeking its recreational effect. But DXM overdose can cause some adverse effects, including brain damage, loss of consciousness, and cardiac arrhythmias, and hence its detection is significant. Herein, an electrochemical sensor based on a Cu-coordinated molecularly imprinted polymer (Cu-MIP) was fabricated for its detection. For constructing the sensor, nitrogen-doped carbon nanosheets (CCNs) were prepared through calcining chitin under an argon atmosphere, and molybdenum disulfide (MoS2) was allowed to grow on their surface. Subsequently, the obtained MoS2/CCNs composite was employed to modify a glassy carbon electrode (GCE), and the Cu-MIP was electrodeposited on the electrode in a Cu-1,10-phenanthroline (Cu-Phen) solution containing DXM, where Cu2+ played a role in facilitating electron transfer and binding DXM. Due to the large specific surface area, good electrocatalytic properties and recognition of the resulting composite, the resulting Cu-MIP/MoS2/CCNs/GCE showed high selectivity and sensitivity. Under optimized experimental conditions, the peak current of DXM and its concentration exhibited a good linear relationship over the concentration range of 0.1-100 µM, and the limit of detection (S/N = 3) was 0.02 µM. Furthermore, the electrochemical sensor presented good stability, and it was successfully used for the determination of DXM in pharmaceutical, human serum and urine samples.

Revolutionizing medicine: Molecularly imprinted polymers as precision tools in cancer diagnosis and antibiotic detection.

Molecularly imprinted polymers (MIPs) are pivotal in medicine, mimicking biological receptors with enhanced specificity and affinity. Comprising templates, functional monomers, and cross-linkers, MIPs form stable three-dimensional polymer networks. Synthetic templates like glycan and aptamers improve efficiency, guiding the molecular imprinting process. Cross-linking determines MIPs' morphology and mechanical stability, with printable hydrogels offering biocompatibility and customizable properties, mimicking native extracellular matrix (ECM) microenvironments. Their versatility finds applications in tissue engineering, soft robotics, regenerative medicine, and wastewater treatment. In cancer research, MIPs excel in both detection and therapy. MIP-based detection systems exhibit superior sensitivity and selectivity for cancer biomarkers. They target nucleic acids, proteins, and exosomes, providing stability, sensitivity, and adaptability. In therapy, MIPs offer solutions to challenges like multidrug resistance, excelling in drug delivery, photodynamic therapy, photothermal therapy, and biological activity regulation. In microbiology, MIPs serve as adsorbents in solid-phase extraction (SPE), efficiently separating and enriching antibiotics during sample preparation. They contribute to bacterial identification, selectively capturing specific strains or species. MIPs aid in detecting antibiotic residues using fluorescent nanostructures and developing sensors for sulfadiazine detection in food samples. In summary, MIPs play a pivotal role in advancing medical technologies with enhanced sensitivity, selectivity, and versatility. Applications range from biomarker detection to innovative cancer therapies, making MIPs indispensable for the accurate determination and monitoring of diverse biological and environmental samples.

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

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

A novel N-CNDs/PAni modified molecular imprinted polymer for ultraselective and sensitive detection of ciprofloxacin in lentic ecosystems: a dual responsive optical sensor.

The research study describes the development of a hybrid nanocomposite called nitro-doped carbon nanodots/polyaniline/molecularly imprinted polymer (N-CNDs/PAni/MIP). This composite is specifically engineered to function as a durable and flexible dual-response sensor to detect and analyze pharmaceutical organic contaminants (POCs). Powder X-Ray diffraction (PXRD), Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) were employed to perform an exhaustive structural and morphological analysis of N-CNDs/PAni/MIP. N-CNDs/PAni/MIP emitted blue luminescence under ultraviolet irradiation and exhibited typical excitation-dependent emission properties. It can act as fluorescent probe for the detection of CIPRO with high selectivity and sensitivity with an IF value of 4.2. Furthermore, N-CNDs/PAni/MIP exhibited high peroxidase-like catalytic behavior. After adding CIPRO to the N-CNDs/PAni/MIP/TMB/H2O2 system, the blue color of the solution faded due to the reduction of blue ox-TMB to colorless TMB. Based on these two phenomena, with CIPRO as the target analyte, the N-CNDs/PAni/MIP dual sensor showed a minimal detection limit of 70 pM for the fluorescent signaling platform and 3.5 nM for the colorimetric probe with a linear range of 0.038-200 nM. The fluorometric and colorimetric assays based on N-CNDs/PAni/MIP for CIPRO detection were then successfully applied to lentic water as well as to tap water samples, demonstrating the sensitivity and dependability of the instrument. Furthermore, the synthesized PVA (N-CNDs/PAni/MIP) films enable the recognition of CIPRO, and these films have the potential to be integrated into portable sensing devices, providing a practical solution for rapid and on-site detection of CIPRO in various samples.