Specific Recognition Sites Research Articles

Ultrasensitive, label-free voltammetric determination of norfloxacin based on molecularly imprinted polymers and Au nanoparticle-functionalized black phosphorus nanosheet nanocomposite

Norfloxacin (NOR) is an antibiotic commonly used to treat humans and food-producing animals. Owing to NOR abuse, its residues are frequently found in animal-derived food products and the surrounding environment. Therefore, development of an efficient analytical technique for the selective determination of trace NOR is greatly significant for food safety and environmental protection. Here, we fabricated an ultrasensitive, label-free molecularly imprinted polymer (MIP) voltammetric sensor for the selective determination of NOR, based on an Au nanoparticle-functionalized black phosphorus nanosheet nanocomposite (BPNS-AuNP) covered by a polypyrrole-imprinted film. BPNS-AuNP nanocomposites were prepared via an in-situ one-step method without the use of reducing agents. The imprinted polypyrrole film was formed on the surface of the BPNS-AuNPs in the presence of NOR. The physical properties and electrochemical behavior of the MIP/BPNS-AuNPs were investigated using various characterization techniques, and the analytical parameters were optimized. We found that BPNS-AuNPs improve the ambient stability and electrocatalytic activity, providing a large surface area for locating a higher number of specific recognition sites. Consequently, the MIP/BPNS-AuNP/GCE showed excellent sensing performance toward NOR, with a wide linear response range (0.1 nM − 10 μM), an extremely low limit of detection (0.012 nM), and extraordinary selectivity. Moreover, the MIP/BPNS-AuNP/GCE was used to determine NOR in various experimental samples with satisfactory results.

Identification of Novel Cas Proteins in Metagenomic Datasets of Microbiomes in Puerto Rican Ecosystems

CRISPR‐Cas9 technology has become one of the most groundbreaking discoveries of the 21st century. CRISPR, which stands for Clustered Regularly Interspaced Short Palindromic Repeats, along with CRISPR‐associated (Cas) proteins, function as an adaptive immune system for many prokaryotic organisms. As a gene editing tool, CRISPR‐Cas9 allows for sequence‐specific targeting, which scientists have exploited in favor of biomedicine, as a way to alter and remove genes and genomic regions altogether in almost all eukaryotic cells. In spite of its great implications in biomedical research, and as a means of studying gene function, CRISPR‐Cas9 has important limitations. Perhaps, most notably, Cas9 interacts with a specific DNA recognition site, known as the protospacer adjacent motif (PAM). In the absence of the correct PAM sequence, Cas9 will be unable to bind DNA and, hence, it will be unable to perform its endonuclease function. While the PAM sequences for the commonly used S. pyogenes Cas9 (SpCas9) is commonly found throughout the human genome, they are not always efficiently positioned to target a particular gene. Our current understanding of Cas9 orthologs is deficient, and the characterization of novel PAM sequences will continue to improve the gene‐editing efficiency of CRISPR technology as we know it. Moreover, the isolation of novel Cas9 and other CRISPR‐associated proteins has and will continue to increase the number of CRISPR applications. Throughout this project, we aim to use functional metagenomics as a vehicle for bioprospecting novel CRISPR‐Cas systems within different environmental samples of Puerto Rico. We analyzed two metagenomic datasets from the microbial and functional diversity of distinct water systems: the Guajataca water reservoir, and the Clara Cave and Empalme Sinkhole waters. Sequencing data was analyzed regarding CRISPR‐Cas analogy through CRISPR databases via CRISPRCasFinder and NCBI‐BLAST. Multiple sequence alignments were conducted to describe conserved regions in Cas genes using the ConSurf server. Several CRISPR‐Cas‐like regions were identified within the metagenomic datasets. Candidate prospects will be analyzed concerning Cas protein identity and function with in vivo and in vitro approaches. Throughout this approach, we expect to unravel previously unexplored CRISPR‐Cas systems, as well as characterizing and describing Cas protein orthologs within these environments respecting PAM sequence specificity and other functional and structural characteristics.

Co3O4-chitosan/biomass-derived porous carbon molecularly imprinted polymer integrated electrode for selective detection of glucose

The detection of glucose (Glu) is of great significance in medical diagnosis, food processing and biotechnology. Rapid, accurate and convenient detection technology is particularly important. Herein, the Co3O4-PC nanocomposite grown on biomass-derived porous carbon (PC) was prepared by hydrothermal method and subsequent air calcination. Chitosan (CS) was electrodeposited on the surface of Co3O4-PC by potentiostatic deposition with Glu as the template molecule. Finally, the template molecule was eluted by cyclic voltammetry to create specific recognition sites for Glu, and a highly selective and stable Glu sensor was constructed. The obtained MIP (molecularly imprinted polymer)-Glu-CS/Co3O4/PC nanocomposites were characterized by scanning electron microscopy, Raman spectroscopy, cyclic voltammetry, chronoamperometry and so on. The results showed that the MIP-Glu-CS/Co3O4-PC had great catalytic performance for Glu detection with a linear range of 12.17 μM-2.3 mM, a detection limit of 4.01 μM, and a sensitivity of 407.5 μA cm−2 mM−1. The sensor has excellent selectivity and stability. This work provides a guide for improving the selectivity of nanozymes.

Peroxymonosulfate-activated molecularly imprinted bimetallic MOFs for targeted removal of PAHs and recovery of biosurfactants from soil washing effluents

Treatment of washing effluents containing high concentrations of surfactants and PAHs remains a critical challenge in surfactant-enhanced soil washing processes. In this study, bimetallic metal–organic frameworks modified with molecularly imprinted polymers, named Al/Co-MOFs@MIP have been synthesized to activate peroxymonosulfate (PMS) at the first time for targeted degradation of phenanthrene from soil washing effluents for biosurfactant recovery. The Al/Co-MOFs@MIP has higher stability, better catalytic performance and excellent selective recognition. The Al/Co-MOFs@MIP has significantly enhanced adsorption of phenanthrene. Electrostatic interactions and functional groups binding between phenanthrene and specific recognition sites led to better selective recognition. Targeted adsorption of phenanthrene caused closer distance between free radicals and pollutants which resulted in higher degradation efficiency. Phenanthrene adsorbed on the Al/Co-MOFs@MIP surface consumes free radicals, thus reducing the attack of oxidative free radicals on rhamnolipids. The EPR and quenching experiments indicated that although both free radicals and non-free radicals made contributions to the degradation of phenanthrene. Phenanthrene is attacked and oxidized by SO4·- and 1O2 through two pathways, including oxalic acid loss, ring cleavage and mineralization. This study indicated that selective phenanthrene degradation could be realized in Al/Co-MOFs@MIP/PMS system due to the synergetic effects including selective adsorption and catalysis of the material.

Ionic liquid modified covalent organic frameworks for efficient detection and adsorption of ReO4–/TcO4–

The tanglesome environments of high radiation and strong acid or alkali lead to the currently reported materials used to detect ReO4− (surrogate for 99TcO4− with nonradioactive) far from meeting the requirements of practical applications. Here, we report the ionic liquids modified covalent organic frameworks (ionic COFs) were applied to detect and adsorb ReO4− for the first time. Ionic COFs are obtained by grafting ionic liquids on the channel walls of COFs. Not only the ionic liquids enhance the fluorescence performance of COFs by expanding the conjugated structure, but bring high-efficiency fluorescence response to ReO4− through introducing specific recognition sites with the detection limit as low as 1.04 μM. Benefiting from the intramolecular charge transfer conducted by hydrogen bond and clear hydrophobic framework, ionic COFs shows ultrafast fluorescence response (2 s) and excellent selectivity to ReO4−, which is quite suitable for on-site and real-time monitoring of ReO4−. Meanwhile, abundant ionic liquids and regular pore channels provide ionic COFs with admirable adsorption kinetics (within 3 min) and superior adsorption capacity (439 mg/g). In other words, the strong-bond ionic COFs overcome the weak stability of other fluorescence sensors of ReO4− and propose a new strategy for ReO4− detection, which offer huge potential to detect and remove 99TcO4−/ReO4− under realistic conditions.

A “signal on/off” biomimetic electrochemiluminescence sensor using titanium carbide nanodots as co-reaction accelerator for ultra-sensitive detection of ciprofloxacin

It is of great significance to explore an efficient and sensitive method for the detection of ciprofloxacin (CIP) for the protection of human health and ecological environment. In this study, a novel molecularly imprinted electrochemiluminescence sensor (MIECLS) was constructed using amino-functional titanium carbide nanodots (TNDs) as co-reactant accelerator in the cathodic electrochemiluminescence system. With K2S2O8 as co-reactant, the obvious cathode luminescence signal of carbon nitride nanosheets (CNNS) can be observed under the synergistic effect of TNDs. TNDs not only advanced the conductivity of CNNS, and the presence of amino group accelerated the reduction of the co-reactant S2O82−, which generated a rich ECL reaction intermediate SO4−• near CNNS, thus greatly enhancing the ECL signal of CNNS. In addition, the proposed MIECLS have good anti-interference, high sensitivity and selectivity by electropolymerization of o-phenylenediamine as functional monomer to form molecularly imprinted polymer (MIP) with specific recognition sites on electrode surface. The MIECLS was applied for determination of CIP, and its ECL intensity was linearly quenched with the increasing concentration of CIP from 5 × 10−9 to 5 × 10−6 mol L−1 with a detection limit of 1.20 × 10−9 mol L−1 (S/N = 3). Futhermore, in the actual sample analysis, the detection results of MIECLS showed good consistency with those of HPLC, indicating that MIECLS has a broad application prospect in the rapid and sensitive analysis of CIP in food samples.

Electrospun molecularly imprinted sodium alginate/polyethylene oxide nanofibrous membranes for selective adsorption of methylene blue

Molecular imprinting technique is an efficient method to improve the selective adsorption capacity for the target pollutant. In this study, sodium alginate/polyethylene oxide molecularly imprinted nanofibrous membrane (SA/PEO-MINM) with average diameter of 185 ± 20 nm was successfully synthesized by electrospinning for selective adsorption of methylene blue (MB). Benefiting from the molecular imprinted technology, the adsorption amount of SA/PEO-MINM for MB was increased by about 65%, significantly higher than the non-imprinted membrane. Results showed that the adsorption equilibrium could be well fitted with Langmuir isotherm model and the maximum adsorption capacity towards MB was 3186.7 mg/g. Kinetic experiments well complied with the Pseudo second order model. Reusability studies indicated that the removal efficiency of MB could maintain 93% of the original adsorption capacity after four consecutive adsorption/desorption cycles. More importantly, the SA/PEO-MINM with high surface area and specific adsorption recognition sites showed excellent selective adsorption capacity in the adsorption experiment of MB and methylene orange mixed dye solution. In general, the SA/PEO-MINM can be successfully applied for the selective removal of MB from dye wastewater.

A camphor-based fluorescent probe with high selectivity and sensitivity for formaldehyde detection in real food samples and living zebrafish

A novel and simple camphor-based fluorescent probe (CH) was synthesized for detecting formaldehyde (FA) with high specificity and efficiency. A significantly enhanced green fluorescence was clearly observed only with the addition of FA because of specific recognition site homoallylamino group of FA. After treating with FA, the homoallylamino group on probe CH was converted to aldehyde group via the 2-aza-Cope rearrangement mechanism, which was demonstrated with high-resolution mass spectrometer (HRMS) analysis and density functional theory (DFT). Moreover, the experiment results manifested that the detection of FA with probe CH can be performed in a nearly perfect aqueous solution with low detection limit, large Stokes shift and wide pH adaptation range. Meanwhile, a simple filter paper, loaded with probe CH, was available to detect gaseous FA. The probe CH was also successfully applied to the detection of FA in real food and water samples. Furthermore, the fluorescence imaging experiment verified that the probe CH can effectively monitor FA in living zebrafish.

Photoelectrochemical determination of diclofenac using oriented single-crystalline TiO2 nanoarray modified with molecularly imprinted polypyrrole.

A novel molecular imprint photoelectrochemical (PEC) sensor has been prepared based on oriented single-crystalline TiO2 nanoarray (TNA) material for sensitive detection of diclofenac (DCF). The TNA obtained by the one-step hydrothermal method was characterized by XRD, SEM, and TEM. Polypyrrole film was formed on the TNA by electrochemical method, and DCF was imprinted on the polymer film as the template molecule. After the removal of DCF, there appeared lots of specific recognition sites that matched template molecules. The experimental results demonstrated that the constructed PEC sensor has good sensitivity and selectivity for the detection of DCF, which can be attributed to the high photoelectric conversion efficiency of TNA and the high selectivity of molecular imprinting technology. The fabricated PEC sensor showed a wide detection range (0.05-1000μM) and a low limit of detection (0.0034μM) for DCF, as well as good repeatability and stability. The proposed PEC sensor provided an effective strategy in the monitoring of environmental pollutants.

Ion-Imprinted Polymer-on-a-Sensor for Copper Detection.

The accumulation of metal ions in the body is caused by human activities and industrial uses. Among these metal ions, copper is the third most abundant ion found in the human body and is indispensable for health because it works as a catalyst in the iron absorption processes. However, high doses of copper ions have been reported to generate various diseases. Different types of sensors are used to detect metal ions for several applications. To design selective and specific recognition sites on the sensor surfaces, molecular imprinting is one of the most used alteration methods to detect targets by mimicking natural recognition molecules. In this study, an ion-imprinted polymer-integrated plasmonic sensor was prepared to selectively detect copper (Cu(II)) ions in real-time. Following different characterization experiments, the Cu(II)-imprinted plasmonic sensor was employed for kinetic, selectivity, and reusability studies. According to the results, it was observed that this sensor can measure with 96% accuracy in the Cu(II) concentration range of 0.04–5 μM in buffer solution. The limit of detection and limit of quantification values were computed as 0.027 µM and 0.089 µM. The results also showed that this plasmonic sensor works successfully not only in a buffer solution but also in complex media such as plasma and urine.

Riboflavin Stabilizes Abasic, Oxidized G-Quadruplex Structures.

The G-quadruplex is a noncanonical fold of DNA commonly found at telomeres and within gene promoter regions of the genome. These guanine-rich sequences are highly susceptible to damages such as base oxidation and depurination, leading to abasic sites. In the present work, we address whether a vacancy, such as an abasic site, in a G-quadruplex serves as a specific ligand recognition site. When the G-tetrad is all guanines, the vacant (abasic) site is recognized and bound by free guanine nucleobase. However, we aim to understand whether the preference for a specific ligand recognition changes with the presence of a guanine oxidation product 8-oxo-7,8-dihydroguanine (OG) adjacent to the vacancy in the tetrad. Using molecular dynamics simulation, circular dichroism, and nuclear magnetic resonance, we examined the ability for riboflavin to stabilize abasic site-containing G-quadruplex structures. Through structural and free energy binding analysis, we observe riboflavin’s ability to stabilize an abasic site-containing G-quadruplex only in the presence of an adjacent OG-modified base. Further, when compared to simulation with the vacancy filled by free guanine, we observe that the free guanine nucleobase is pushed outside of the tetrad by OG to interact with other parts of the structure, including loop residues. These results support the preference of riboflavin over free guanine to fill an OG-adjacent G-quadruplex abasic vacancy.

Construction of surface molecularly imprinted photonic hydrogel sensors with high sensitivity

In comparison with molecularly imprinted photonic hydrogel (MIPH) with specific molecular recognition sites inside matrix, surface molecularly imprinted photonic hydrogel (S-MIPH) is more competitive as a molecular sensor due to presence of molecular recognition sites distributed on surface of hydrogel wall. Nevertheless, the construction of S-MIPH sensors is still challenging owing to the absence of interaction between traditional colloids and imprinted molecules. Here we report the construction of S-MIPH sensors by using poly (styrene-acrylic acid) colloids with abundant carboxyl group that are capable of binding imprinted molecules readily through hydrogen interaction. Benefit from this novel motif, S-MIPH sensors can be readily constructed by self-assembly of poly (styrene-acrylic acid) colloids binding imprinted molecules, the polymerization of precursor solution, as well as finally removal of colloids and imprinted molecules. The self-assembly of poly (styrene-acrylic acid) colloids binding imprinted molecules was investigated in detail. The as-prepared sensor delivers high sensitivity (as low as 10−9 mol L−1), rapid response speed (< 60 s), and good selectivity owing to the 3D macroporous structure and specific molecular recognition sites that are well distributed on surface of hydrogel wall. Additionally, the developed sensors show good sensing performance even in commercial milk, showing great potential for real application.

A molecularly imprinted electrochemical sensors based on bamboo-like carbon nanotubes loaded with nickel nanoclusters for highly selective detection of cortisol

Nitrogen doped bamboo-liked carbon nanotubes loaded with nickel nanoclusters were prepared by single-pot pyrolysis method. On this basis, a molecularly imprinted electrochemical sensor (MIECS) with the specific recognition sites of cortisol was studied. Using o-phenylenediamine as functional monomer and cortisone as template, molecularly imprinted polymer films were prepared by simple and controllable electropolymerization. After a series of optimized conditions, the MIECS shows a wide linear range of 10−14 M to 10−9 M for cortisol with a low detection limit at 2.37 × 10−15 M. Moreover, this sensing platform has been applied to the detection of cortisol in saliva samples and satisfactory results has been obtained.

Non-toxic fluorescent molecularly imprinted hydrogel based on wood-derived cellulose nanocrystals and carbon dots for efficient sorption and sensitive detection of tetracycline

For clean, effective, and high value-added use of wood, a novel non-toxic fluorescent molecularly imprinted hydrogel (FMIH) was prepared based on wood-derived cellulose nanocrystals and carbon dots for efficient sorption and sensitive detection of tetracycline (TC). The FMIH’s morphology, chemical structure, optical properties and non-cytotoxicity were investigated. The adsorption performance of FMIH toward TC was studied, indicating that the sorption data were well fitted by the Langmuir and Pseudo-second-order models, and the maximum sorption capacity was 544.4 mg/g. An evaluation of the detection performance of FMIH toward TC showed its excellent selectivity and sensitivity to TC with the detection limit of 0.11 μg/L. Mechanism analysis confirmed that the efficient sorption and sensitive detection was due to specific molecular recognition sites introduced by wood-derived cellulose nanocrystals and carbon dots. Moreover, a cost analysis performed for FMIH and commercial activated carbon (CAC) showed that the cost of removing 1 g of TC using FMIH was almost thirty-four times cheaper than that of CAC. This work could provide a new way for using wood to produce a low-cost, multifunctional, and green adsorbent for removing antibiotics.

An electrochemically induced dual-site adsorption composite film of Ni-MOF derivative/NiCo LDH for selective bromide-ion extraction

An electrochemically induced electrode with bromide ion (Br-) dual adsorption sites was obtained by in-situ growing of Ni-MOF derivative/NiCo layered double hydroxide (Ni-MOF(D)/NiCo LDH) composite film on the stainless-steel wire mesh via an electrodeposition-assisted solvothermal method, which exhibited excellent Br- selectivity from ionic mixture solutions of Br-, NO3– and I- in an electrochemically switched ion exchange (ESIX) system. The Br- extraction capacity was as high as 126.30 mg·g−1 and the separation factors of Br-/NO3– and Br-/I- were 8.29 and 4.83 respectively. Combining the simulation and experimental results, it was confirmed that the highly efficient selective extraction of Br- in neutral solution should be derived from the dual-site (i.e., electrochemically induced laminate metal coordination sites and interlayer anion exchange sites of NiCo LDH) adsorption. Furthermore, the electrode demonstrated superior adsorption–desorption performance and electrochemical stability because of the in-situ growth strategy, which enhanced the binding force between NiCo LDH and substrate and improved the electrical conductivity of NiCo LDH, and provided a storage space for Br-. This study served deep understanding of ions selective extraction mechanism of LDH-based materials in the ESIX process, which could be a novel reaction concept for the design of those electrodes with specific recognition sites in the applications of them in other fields such as supercapacitors, sensors and batteries.

Two-stage nicking enzyme signal amplification (NESA)-based biosensing platform for the ultrasensitive electrochemical detection of pathogenic bacteria.

The sensitive and selective detection of pathogenic bacteria represents an essential approach in food safety analysis and clinical diagnostics. We report the development of a simple, rapid, and low-cost electrochemical biosensing strategy for the detection of pathogenic bacteria with ultrasensitivity and high specificity. The biosensor relies on the target and aptamer binding-triggered two-stage nicking enzyme signal amplification (NESA) and three-way junction probe-mediated electrochemical signal transduction. In the presence of the target S. typhimurium, the specific binding of S. typhimurium and aptamer results in the release of a primer, which hybridizes with HAP1 and initiates an extension reaction with the aid of polymerase and dNTPs. A specific recognition site for Nt.BsmaI is generated in the DNA duplex; thus, the produced DNA is nicked and the secondary primer is released (named recycle I). Subsequently, the reaction solution supplemented with a helper DNA is dropped on the electrode surface, and a three-way junction probe containing a specific recognition site for Nt.BsmaI is thus formed. The MB-labeled probe is nicked with the help of Nt.BsmaI and the dissociated primer-helper DNA duplex combines with another HAP2 (named recycle II). Thus, a remarkably decreased electrochemical signal is generated because the electroactive MB is far away from the electrode surface. As far as we know, this work is the first time that NESA and three-way junction probe-mediated electrochemical signal transduction has been used for pathogenic bacteria detection. Under optimal conditions, the results reveal that the calibration plot obtained for S. typhimurium is approximately linear from 9.6 to 9.6 × 105 cfu mL-1 with the limit of detection of 8 cfu mL-1. Additionally, the proposed strategy has been successfully applied to the quantitative assay of S. typhimurium in the real samples. Therefore, the NESA-based biosensing strategy might create a useful and practical platform for pathogenic bacteria identification, and the related food safety analysis and clinical diagnosis.

Function and Mechanism of RGD in Bone and Cartilage Tissue Engineering.

Bone and cartilage injury is common, tissue engineered scaffolds are potential means to repair. Because most of the scaffold materials used in bone and cartilage tissue engineering are bio-inert, it is necessary to increase the cellular adhesion ability of during tissue engineering reconstruction. The Arginine - Glycine - Aspartic acid (Arg-Gly-Asp, RGD) peptide family is considered as a specific recognition site for the integrin receptors. Integrin receptors are key regulators of cell-cell and cell-extracellular microenvironment communication. Therefore, the RGD polypeptide families are considered as suitable candidates for treatment of a variety of diseases and for the regeneration of various tissues and organs. Many scaffold material for tissue engineering and has been approved by US Food and Drug Administration (FDA) for human using. The application of RGD peptides in bone and cartilage tissue engineering was reported seldom. Only a few reviews have summarized the applications of RGD peptide with alloy, bone cements, and PCL in bone tissue engineering. Herein, we summarize the application progress of RGD in bone and cartilage tissue engineering, discuss the effects of structure, sequence, concentration, mechanical stimulation, physicochemical stimulation, and time stimulation of RGD peptide on cells differentiation, and introduce the mechanism of RGD peptide through integrin in the field of bone and cartilage tissue engineering.

Filling gaps of genome scaffolds via probabilistic searching optical maps against assembly graph

BackgroundOptical maps record locations of specific enzyme recognition sites within long genome fragments. This long-distance information enables aligning genome assembly contigs onto optical maps and ordering contigs into scaffolds. The generated scaffolds, however, often contain a large amount of gaps. To fill these gaps, a feasible way is to search genome assembly graph for the best-matching contig paths that connect boundary contigs of gaps. The combination of searching and evaluation procedures might be “searching followed by evaluation”, which is infeasible for long gaps, or “searching by evaluation”, which heavily relies on heuristics and thus usually yields unreliable contig paths.ResultsWe here report an accurate and efficient approach to filling gaps of genome scaffolds with aids of optical maps. Using simulated data from 12 species and real data from 3 species, we demonstrate the successful application of our approach in gap filling with improved accuracy and completeness of genome scaffolds.ConclusionOur approach applies a sequential Bayesian updating technique to measure the similarity between optical maps and candidate contig paths. Using this similarity to guide path searching, our approach achieves higher accuracy than the existing “searching by evaluation” strategy that relies on heuristics. Furthermore, unlike the “searching followed by evaluation” strategy enumerating all possible paths, our approach prunes the unlikely sub-paths and extends the highly-probable ones only, thus significantly increasing searching efficiency.

Molecularly Imprinted Polymers (MIPs) in Sensors for Environmental and Biomedical Applications: A Review.

Molecular imprinted polymers are custom made materials with specific recognition sites for a target molecule. Their specificity and the variety of materials and physical shapes in which they can be fabricated make them ideal components for sensing platforms. Despite their excellent properties, MIP-based sensors have rarely left the academic laboratory environment. This work presents a comprehensive review of recent reports in the environmental and biomedical fields, with a focus on electrochemical and optical signaling mechanisms. The discussion aims to identify knowledge gaps that hinder the translation of MIP-based technology from research laboratories to commercialization.

A novel electrochemiluminescence sensor based on MXene and sodium ascorbate coordinated amplification CNNS signal strategy for ultrasensitive and selective determination of histamine

A highly selective and sensitive molecularly imprinted electrochemiluminescence sensor (MIECLS) was fabricated on the basis of carbon nitride nanosheets (CNNS) and MXene-Ti3C2 for the determination of histamine (HA) in foods in this study. The introduction of sodium ascorbate (NaAsc) into the electrochemiluminescence (ECL) system not only prevented Ti3C2 from aggregation to a certain extent, but also promoted the generation of more SO4− • by the S2O82-, which enhancing the ECL intensity of CNNS. Molecularly imprinted polymers (MIP) with specific recognition sites formed on the electrode surface by electropolymerization endowed the sensor with high sensitivity and selectivity. Taking advantage of the MIECLS, the sensitive and selective detection of HA has been achieved in a linear range 5 × 10−9 to 1 × 10−4 mol L−1 with a detection limit of 1.71 × 10−9 mol L−1. In the actual sample analysis, the detection results with MIECLS were consistent with the obtained from HPLC, demonstrating that the MIECLS will have a great potential application in rapid and sensitive determination of HA analysis in actual samples.