Analytical applications of chemiluminescence systems assisted by carbon nanostructures

Atomic Dispersion of Zn2+ on N-Doped Carbon Materials: From Non-Activity to High Activity for Catalyzing Luminol-H2O2 Chemiluminescence

Fe and Co single-atom catalysts (SACs) have been widely explored in many fields, while Zn SACs are still in their infancy stage. Herein, we unexpectedly found that atomically dispersed Zn²⁺ on N-doped carbon material (Zn-N-C) exhibited high catalytic activity on luminol-H₂O₂ chemiluminescence (CL) reaction. The Zn-N-C SACs were readily prepared through simple pyrolyzation of the cheap precursors (dopamine and ZnCl₂). The mechanism of Zn SAC-catalyzed CL reaction of luminol-H₂O₂ was investigated in detail. The activity of Zn SACs originated from the Zn-N sites in the Zn-N-C structure. The monoatomic dispersion makes Zn²⁺ catalytic performance change from no activity to high activity in luminol-H₂O₂ CL reaction. This study demonstrated the particularity of the monatomic metal catalyst over the conventional metal ion. This work provides the unprecedented perspective for design of new metal SACs in CL reaction.

Synthesis of rod-like CeO2 nanoparticles and their application to catalyze the luminal-O2 chemiluminescence reaction used in the determination of oxcarbazepine and ascorbic acid

Rod-like CeO₂ nanoparticles (NPs) were produced by the quick precipitation approach and employed as a catalyzer to increase the chemiluminescence (CL) intensity of the luminol-O₂ reaction. The transmission electron microscopy (TEM) images of the CeO₂ NPs showed that rod-like particles with the length and diameter about 15 nm and 5 nm, respectively, were produced. Furthermore, pharmaceuticals including oxcarbazepine (OXP) and ascorbic acid (AA) showed an inhibitory effect against the CL intensity such that the more concentration of the pharmaceuticals, the less was the CL intensity. Therefore, the new CeO₂ NPs-luminol-O₂ CL reaction was developed to determine OXP and AA in the pharmaceutical formulations. It is the first CL method established for the quantification of OXP. The linear dynamic range of this method for OXP was from 6.0 × 10^-7 to 6.0 × 10^-5 mol L^-1 and for AA from 1.0 × 10^-6 to 1.0 × 10^-4 mol L^-1.

CuS nanoparticles-enhanced luminol-O2 chemiluminescence reaction used for determination of paracetamol and vancomycin

A new chemiluminescence (CL) method was proposed to measure two widely used drugs, including paracetamol (PCM) and vancomycin (VAN). The CL reaction used was the CuS nanoparticles (CuS NPs)-luminol-O₂ system. In this system, CuS NPs played the role of catalyst and increased the CL intensity. CuS NPs were easily synthesized by quick-precipitation. CuS NPs were characterized by spectroscopic techniques, and the mean size of NPs was estimated to be about 9 nm. In the developed CL methods, PCM and VAN decreased the CL intensity. In the proposed method, the linear concentration ranges were 4.0 × 10^-5-4.0 × 10^-4 mol L^-1 of PCM and 2.0 × 10^-5-6.0 × 10^-4 mol L^-1 of VAN. The limit of detections were 2.9 × 10^-5 mol L^-1 and 8.9 × 10^-6 mol L^-1 for PCM and VAN, respectively. The relative standard deviations (RSD) of the CL method were 2.99 and 4.31 (n = 6) for the determination of 3.0 × 10^-4 mol L^-1 PCM and VAN, respectively. It was also shown that the CL methods can measure PCM and VAN concentrations in various real samples.

Surface molecularly imprinted polymers fabricated by differential UV-vis spectra and reverse prediction method for the enrichment and determination of sterigmatocystin

A novel magnetic molecularly imprinted polymers (MMIPs) with a new functional monomer Triallyl isocyanurate was synthesized successfully to enrich and detect sterigmatocystin (STG) in wheat samples. The differential UV-vis spectra and the reverse prediction method were selected to achieve the optimal synthesis conditions of the MMIPs, which were characterized well. The adsorption experiment showed that MMIPs have high selectivity and sensitivity. A magnetic solid phase extraction combined with high performance liquid chromatography (MSPE-HPLC) method based on the MMIPs was successfully established with the optimal extraction condition. The linear range and RSD were 1.8-25 ng·g^-1 and 2.6-4.1%, respectively. The recovery of this method was 87.6-96.9% and the limit of detection (LOD) was 0.63 ng·g^-1. The excellent sensitivity and selectivity of this method were confirmed by experiment of the extraction and detection of STG in wheat extracts. This work extends the use of molecular imprinting in mycotoxins applications.

A Highly Efficient Chemiluminescence System Based on an Enhancing Effect of Ag Nanoclusters/Graphene Quantum Dots Mixture for Ultrasensitive Detection of Rabeprazole

Herein, an efficient chemiluminescence (CL) reaction with a high emission intensity is reported based on a synergistic improving effect of silver nanoclusters (AgNCs) and graphene quantum dots (GQDs). First, the syntheses of AgNCs and GQDs were simply performed by the chemical reducing of AgNO₃ and a thermal treatment of glucose, respectively. After the characterization steps, the beneficial behavior of the prepared nanomaterial was investigated in CL systems. The oxidation reaction of KMnO₄-rhodamine B produced weak CL emission. However, the presence of AgNCs and GQDs led to a synergetic enhancing effect, and thus higher emission was obtained. A possible mechanism was investigated for this effect using absorption and fluorescence experiments. Furthermore, rabeprazole showed a relatively selective enhancing impact on the CL emission. The CL intensity was linearly increased in the rabeprazole concentration range of 4 - 133 ng mL^-1 with a detection limit (3S_b/m) of 1.1 ng mL^-1. The developed CL method was utilized for the measurement of Rbp in biological samples with acceptable precision and accuracy.

Detection of chloramphenicol in meat with a chemiluminescence resonance energy transfer platform based on molecularly imprinted graphene

In this study, a novel composite was synthesized by polymerizing the dummy-template molecularly imprinted microspheres on the surface of magnetic graphene. This composite was used as recognition reagent and energy acceptor to develop a platform for determination of chloramphenicol according to the principle of chemiluminescence resonance energy transfer. The light signal was induced with luminolH₂O₂4-(imidazole-1-yl)phenol system, and the chemiluminescence intensity was positively correlated with the analyte concentration. The limit of detection for chloramphenicol in meat sample was 2.0 pg/g, and the recoveries from the standard fortified blank meat sample were in the range of 69.5%-97.3%. Furthermore, one single assay could be finished within 10 min, and the magnetic composite could be reused for at least thirty times. Therefore, this platform could be used as a rapid, simple, sensitive, accurate and recyclable tool for screening the residue of chloramphenicol in meat.

Ultrasensitive chemiluminescence assay for cimetidine detection based on the synergistic improving effect of Au nanoclusters and graphene quantum dots

A novel and sensitive chemiluminescence (CL) procedure based on the synergetic catalytic effects of gold nanoclusters (Au NCs) and graphene quantum dots (GQDs) was developed for the reliable measurement of cimetidine (CM). The initial experiments showed that the KMnO₄ -based oxidation of alkaline rhodamine B (RhoB) generated a very weak CL emission, which was intensively enhanced in the simultaneous presence of Au NCs and GQDs. CL intermediates can be adsorbed and gathered on the surface of Au NCs, becoming more stable. GQDs participate in the energy transferring processes and facilitate them. These improving effects were simultaneously obtained by adding both Au NCs and GQDs into the RhoB-KMnO₄ reaction. Consequently, the increasing effect of the Au NCs/GQDs mixture was more than that of pure Au NCs or GQDs, and a new nano-assisted powerful CL system was achieved. Furthermore, a marked quenching in the emission of the introduced CL system was observed in the presence of CM, so the system was examined to design a sensitive sensor for CM. After optimization of influencing parameters, the linear lessening in CL emission intensity of KMnO₄ -RhoB-Au NCs/GQDs was verified for CM concentrations in the range 0.8-200 ng ml^-1 . The limit of detection (3S_b /m) was 0.3 ng ml^-1 . Despite being a simple CL method, good sensitivity was obtained for CM detection with reliable results for CM determination in human urine samples.

Aptasensors as the future of antibiotics test kits-a case study of the aptamer application in the chloramphenicol detection

Antibiotics are a type of antimicrobial drug with the ubiquitous presence in foodstuff that effectively applied to treat the diseases and promote the animal growth worldwide. Chloramphenicol as one of the antibiotics with the broad action spectrum against Gram-positive and Gram-negative bacteria is widely applied for the effective treatment of infectious diseases in humans and animals. Unfortunately, the serious side effects of chloramphenicol, such as aplastic anemia, kidney damage, nausea, and diarrhea restrict its application in foodstuff and biomedical fields. Development of the sufficiently sensitive methods to detect chloramphenicol residues in food and clinical diagnosis seems to be an essential demand. Biosensors have been introduced as the promising tools to overcome the requirement. As one of the newest types of the biosensors, aptamer-based biosensors (aptasensors) are the efficient sensing platforms for the chloramphenicol monitoring. In the present review, we summarize the recent achievements of the accessible aptasensors for qualitative detection and quantitative determination of chloramphenicol as a candidate of the antibiotics. The present chloramphenicol aptasensors can be classified in two main optical and electrochemical categories. Also, the other formats of the aptasensing assays like the high performance liquid chromatography (HPLC) and microchip electrophoresis (MCE) have been reviewed. The enormous interest in utilizing the diverse nanomaterials is also highlighted in the fabrication of the chloramphenicol aptasensors. Finally, some results are presented based on the advantages and disadvantages of the studied aptasensors to achieve a promising perspective for designing the novel antibiotics test kits.

Ultrasensitive quantitative detection of small molecules with rapid lateral-flow assay based on high-affinity bifunctional ligand and magnetic nanolabels

An ultrasensitive lateral-flow assay is developed for rapid quantitative detection of small molecules on-site. The conceptual novelty, which transfers lateral-flow assays to the category of highly sensitive quantitative systems, is due to employment of a bifunctional ligand combined with volumetric registration of magnetic nanolabels. The ligand provides extremely high affinity for trapping the nanolabels and, simultaneously, efficiently competes with the analyzed molecules for the limited quantity of antigen-binding sites on the nanolabels. The developed assay has been demonstrated as the first express method for measuring in human serum of free thyroxine (fT4). The limit of detection is 20 fМ or 16 fg/ml at the assay time <30 min with the dynamic range of 3 orders. Besides, we present the results of first characterization of kinetic parameters of interaction between free thyroxine and monoclonal antibody, as well as of competitive relationship between fT4 and fT4-biotin. The proposed universal platform can be used for ultrasensitive detection of small molecules in human in vitro diagnostics, veterinary, biosafety and counter-terrorism, food quality control, environmental monitoring, etc., as well as for search of new, previously undetectable, diagnostic markers in medicine.

Recent advances and developments on integrating nanotechnology with chemiluminescence assays

Chemiluminescence (CL) techniques are extensively utilized for detection of analytes due to their high sensitivity, rapidity and selectivity. With the advent of nanotechnology and incorporation of the nanoparticles in the CL system has revolutionized the assays due to their unique optical and mechanical properties. Several CL-based reactions have been developed where these nanoparticle based CL sensors have evolved as excellent prospects for sensing in various analytical applications. This review article addresses the nanoparticles based CL detection system that are recently developed, the mechanisms has been summarized and the role of luminophors have been discussed. This article critically analyzes the optimal conditions for the CL detection along with quantitative assessment of the analytes. We have included the use of semiconductor nanoparticles, metal nanoparticles, graphene based nanostructures, mesoporous nanospheres, layered double hydroxides, clays for CL detection. The scope and application of these nanoscale material based CL system in various branches of science and technology including chemistry, biomedical applications, pharmaceutics, food, environmental and toxicological applications has been critically summarized.

Flow analysis with chemiluminescence detection: Recent advances and applications

This article highlights the most important developments in flow analysis with chemiluminescence (CL) detection, describing different flow systems that are compatible with CL detection, detector designs, commonly applied CL reactions and approaches to sample treatment. Recent applications of flow analysis with CL detection (focusing on outputs published since 2010) are also presented. Applications are classified by sample matrix, covering foods and beverages, environmental matrices, pharmaceuticals and biological fluids. Comprehensive tables are provided for each area, listing the specific sample matrix, CL reaction used, linear range, limit of detection and sample treatment for each analyte. Finally, recent and emerging trends in the field are also discussed.

Determination of dihydralazine based on chemiluminescence resonance energy transfer of hollow carbon nanodots

The famous weak chemiluminescence (CL) system of potassium permanganate and sodium bisulfite (KMnO₄-HSO₃^-) was enhanced by the hollow fluorescent carbon nanodots (HCNs). The investigation of mechanism revealed that the enhanced CL was induced by the excited-state HCNs (HCNs^⁎), which could be produced from the electron-transfer annihilation of positively charged HCNs (HCNs⁺) and negatively charged HCNs (HCNs^-) as well as by CL resonance energy transfer (CRET) from excited SO₂ (SO₂^⁎)/¹O₂ to HCNs. The dihydralazine sulfate (DHZS) had a diminishing effect on the CL of HCNs-KMnO₄-HSO₃^- system due to the competitive consumption of O₂^-. Under the optimal conditions, the reduced CL signal with the concentration of DHZS was linear in the range of 1.0×10^-7-7.0×10^-5mol/L with a detection limit of 3.0×10^-8mol/L. The relative standard deviation for seven repeated determination of 5.0×10^-6mol/L DHZS was 2.1%. The established method was applied to the determination of DHZS in pharmaceutical preparations, human urine and plasma samples with good precision and accuracy.

Chemiluminescence detection of trace iodide with flow injection analysis of KMnO4 -carbon dots system

Ultra-weak chemiluminescence (CL) from the reaction of iodide and KMnO₄ was strongly enhanced by carbon nanodots (CNDs) in an acidic medium. The CL intensity was directly proportional to the concentration of iodide in the solution. Therefore, a flow-injection CL system with high sensitivity, selectivity and reproducibility is proposed for the determination of iodide. The proposed method exhibited advantages over a linear range of 3.0 × 10^-6 -1.0 × 10^-4  mol/L and had a detection limit of 3.5 × 10^-7  mol/L. The method was successfully applied to the evaluation of iodide in food samples with recoveries of between 96 and 103%. The relative standard deviations were 2.1 and 4.1% for intra- and inter-assay precision, respectively.

Hybrid Magnetic-DNA Directed Immobilisation Approach for Efficient Protein Capture and Detection on Microfluidic Platforms

In this study, a hybrid magnetic-DNA directed immobilisation approach is presented to enhance protein capture and detection on a microfluidic platform. DNA-modified magnetic nanoparticles are added in a solution to capture fluorescently labelled immunocomplexes to be detected optically. A magnetic set-up composed of cubic permanent magnets and a microchannel was designed and implemented based on finite element analysis results to efficiently concentrate the nanoparticles only over a defined area of the microchannel as the sensing zone. This in turn, led to the fluorescence emission localisation and the searching area reduction. Also, compared to processes in which the immunocomplex is formed directly on the surface, the proposed approach provides a lower steric hindrance, higher mass transfer, lower equilibrium time, and more surface concentration of the captured targets leading to a faster and more sensitive detection. As a proof-of-concept, the set-up is capable of detecting prostate-specific membrane antigen with concentrations down to 0.7 nM. Our findings suggest that the approach holds a great promise for applications in clinical assays and disease diagnosis.

Carbon nanostructures in biology and medicine

Carbon nanostructures have unique physical, chemical, and electrical properties, which have attracted great interest from scientists. Carbon dots, carbon nanotubes, graphene and other carbon nanomaterials are being successfully implemented in electrochemical sensing, biomedical and biological imaging.

A graphene quantum dot-assisted morin–KMnO4 chemiluminescence system for the precise recognition of cypermethrin

A novel and efficient chemiluminescence (CL) probe was developed for cypermethrin (CYPM) based on the sensitizing effect of graphene quantum dots (GQDs) on the morin–KMnO₄ CL reaction.

Molecularly imprinted polymers on multi-walled carbon nanotubes as an efficient absorbent for preconcentration of morphine and its chemiluminometric determination

A simple and selective method was described for the determination of morphine based on its preconcentration by molecularly imprinted polymers on multi-walled carbon nanotubes prior to its chemiluminometric recognition.