Magnetic Separation Technique Research Articles

Investigation on modified Linz-Donawitz slag for the treatment of Pb2+ ion-laden wastewater - A slag utilization sustainable approach

The present study investigated the adsorptive chemistry of Pb2+ ions eradication using modified Linz-Donawitz slag (LDS), a byproduct of steelmaking industries. The processing of LDS was carried out using a magnetic separation technique followed by planetary micro-crushing. The morphology of surface texture and elemental composition of LDS were examined using SEM and EDS techniques, respectively. XRD and FTIR analysis revealed that the divalent cation of Pb2+ was replaced by Ca2+ to form metal silicate (Pb2SiO4) and ferrite (Pb2Fe2O5) through ion exchange and finally precipitated. The experiment data best fitted Langmuir isotherm and showed excellent adsorption capacity of LDS for Pb2+ adsorption (479 mg/g). Thermodynamic parameters, Gibbs free energy (ΔGo), and enthalpy change (ΔHo) indicated the adsorption was spontaneous and endothermic. The leachability study done by the ICP-OES technique suggested the possibility of immobilizing Ca and Si due to the dissolution of CaO and SiO2. The study demonstrated the potential of LDS for treating Pb2+ ions as part of the waste utilization of the steel industry for a sustainable approach.

A new eco-friendly approach for recovery of iron from copper smelting slag: Using CO2 and Cl2 recycling strategies

Copper smelting slag (CSS) is a by-product of modern copper production. In this study, iron resources were extracted from copper smelting slag using chlorine roasting and magnetic separation techniques for the first time. The results showed that hydrogen could reduce the ferrous chloride on the surface of the pellet to environmentally friendly iron, followed by the complete reduction of the ferrous chloride inside the pellet, thus increasing the metallic iron content in the roasted ore. Finally, the concentrate with a TFe (total iron) mass fraction of 73.41 wt% and iron recovery of 86.50 % was obtained, and XRF, XRD, and XPS analysis showed that iron is mainly enriched in the concentrate, and calcium, silicon, aluminum, and other elements are mainly enriched in the tailing. The innovative addition of recyclable additives in the roasting process not only reduces the production cost but also plays an important role in the current total environmental protection and environmentally sustainable development. Analytical methods such as thermodynamic evaluation, evolutionary trends of key elemental compounds, and molecular simulation were used to fully characterize the complex chemical processes of the chlorination roasting process. This study provides theoretical strategies for the cleaning of CSS and facilitates the industrial implementation of technologies for efficient and economical extraction of iron from CSS.

Biotite and ZnO embedded carbon aerogel composite for enhanced photocatalytic activity to degrade ciprofloxacin under sunlight stimulation

This study was explored the photocatalytic efficiency of biotite and ZnO embedded carbon aerogel (CA) photocatalyst to degrade ciprofloxacin (CIP) antibiotic from an aqueous medium by sunlight harvesting. CA came from waste newspaper through pyrolysis technique. Biotite was extracted from Bramapurta River's sand through high-tension magnetic separation techniques. The developed catalyst was characterized by applying FESEM, EDS, XRD, and XPS. The bandgap (1.69 eV) of the catalyst was determined from Tauc's plot. The photocatalytic study showed that, optimum degradation was achieved at 98.471 %, 84.576 %, 77.997 % and 59.607 % for 2, 5, 10 and 20 mg/L CIP containing solution respectively in 180 min at its natural pH applying only employing 0.25 g/L dosage. Moreover, in the pH study, catalyst showed maximum degradation 88.773 % for 5 mg/L CIP containing solution at pH 7 exposing the same irradiation time and dosage. The degradation followed pseudo-first-order kinetics with a maximum rate constant of 0.01831 min−1 which attributes to the first degradation of CIP through ROS. The scavenger test suggested that •OH− and e− played a vital role in the photodegradation process. Regeneration studies confirmed that photocatalysts showed better degradation efficiency until five cycles. Fusion of metal oxides in the catalyst might play a vital role in the multiple photodegradation cycles without losing stability of the composite. FESEM, EDS, and XPS characterization of the spent catalyst was performed for understanding its morphological and chemical change. An antimicrobial study was performed to confirm its efficiency against of gram-negative bacteria (E. coli) and gram-positive bacteria (S. aureus), which suggested that the catalyst is very effective in destroying gram-negative bacteria compared to gram-positive bacteria.

A New Eco-friendly Approach for Recovery of Iron from Copper Smelting Slag: Using CO2 and Cl2 Recycling Strategies

Copper smelting slag (CSS) is a by-product of modern copper production. In this study, iron resources were extracted from copper smelting slag using chlorine roasting and magnetic separation techniques for the first time. The results showed that hydrogen could reduce the ferrous chloride on the surface of the pellet to environmentally friendly iron, followed by the complete reduction of the ferrous chloride inside the pellet, thus increasing the metallic iron content in the roasted ore. Finally, the concentrate with a TFe (total iron) mass fraction of 73.41wt% and iron recovery of 86.50% was obtained, and XRF, XRD, and XPS analysis showed that iron is mainly enriched in the concentrate, and calcium, silicon, aluminum, and other elements are mainly enriched in the tailing. The innovative addition of recyclable additives in the roasting process not only reduces the production cost but also plays an important role in the current total environmental protection and environmentally sustainable development. Analytical methods such as thermodynamic evaluation, evolutionary trends of key elemental compounds, and molecular simulation were used to fully characterize the complex chemical processes of the chlorination roasting process. This study provides theoretical strategies for the cleaning of CSS and facilitates the industrial implementation of technologies for efficient and economical extraction of iron from CSS.

Experimental research on combined magnetic separation and flotation for coal gasification fine slag

ABSTRACT To address the challenging issue of achieving high-precision carbon-ash separation in coal gasification fine slag, magnetic separation and flotation techniques were employed to study their respective separation effect. Optimization tests were conducted to determine the optimal magnetic field gradient and magnetic field intensity, and the ash content of magnetic separation concentrates was 72.18%, with a reduction of 7.28% compared to the sample. Additionally, the magnetic separation tailings exhibited an ash content of 93.99%. Through flotation tests, the optimum conditions for kerosene and composite collector was established. The ash content of flotation concentrates decreased by 16.39% compared to the sample, and the ash content of flotation tailings was 95.83%. A comparative analysis revealed that the combined separation process outperforms single separation methods in reducing the ash content of the concentrates, and realize the further quality improvement and separation effect. Detailed analysis of magnetic characteristics and XRD, XPS analysis studies on the sample and the products, indicated that the magnetic separation effectively pre-removes a certain amount of magnetic high ash minerals. Furthermore, the collector treatment significantly increased hydrophobicity difference between residual carbon and ash matter, which ultimately enhancing the flotation effect.

Magnetic Ion-Imprinted Materials for Selective Adsorption of Cr(VI): Adsorption Behavior and Mechanism Study.

With the increase of hexavalent Cr(VI) wastewater discharged from industrial production, it seriously pollutes water bodies and poses a risk to human health. Adsorption is used as an effective means to treat Cr(VI), but its effectiveness is affected by pH, and the adsorption performance decreases when acidity is strong. Furthermore, research on the mechanism of Cr(VI) adsorption using DFT calculations needs to be developed. This study focuses on the development of magnetically responsive core-shell nano-ion imprinted materials (Fe3O4@GO@IIP) through magnetic separation and surface imprinting techniques. Characterization techniques including FT-IR, XRD, and EDS confirmed the core-shell nanostructure of Fe3O4@GO@IIP. Batch adsorption experiments and model simulations demonstrated the exceptional adsorption capacity of Fe3O4@GO@IIP for Cr(VI) in strongly acidic solutions (pH = 1), reaching a maximum of 89.18 mg/g. The adsorption mechanism was elucidated through XPS and DFT calculations, revealing that Fe3O4@GO@IIP operates through electrostatic interactions and chemical adsorption, with charge transfer dynamics quantified during the process. This research provides new insights for addressing Cr(VI) treatment in highly acidic environments.

Conventional technologies and recent developments in the nanotechnological approach for the remediation of persistent organic pollutants

ABSTRACT Persistent organic pollutants (POPs) are one of the important concerns in the environmental sciences and ecotoxicology fields. Various deadly illnesses and environmental problems are caused by them. It is a major issue in society that there are no new and effective ways to eliminate POPs from the atmosphere. Nanotechnology is a rapidly developing area that has uses in every aspect of life. A lot of attention is being paid to the investigation of novel synthetic methods for shaping and controlling the size of nanomaterials due to their outstanding uses and qualities. One of the most significant groups of nanoparticles is the magnetic nanoparticles. A novel class of magnetic separation techniques for water treatment has been made possible through the utilization of magnetic nanoparticles as nano adsorbents. Our aim in this study is to give a concise, focused review of POP, emphasize the sources, types, and potentially hazardous impacts they have on living organisms, and to offer some observations on their detection and monitoring strategies. To highlight specific conventional removal technologies of importance, as well as recent advancements such as nanotechnology and magnetic nanoparticles, including their synthesis methods. Finally, hybrid nanotechnology for POP removal has been investigated.

Rapid identification of MRSA directly from sterile body fluids by co-magnetic bead enrichment and MALDI-TOF mass spectrometry

As a result of the extensive use of antibiotics, methicillin-resistant Staphylococcus aureus (MRSA) has emerged, leading to serious clinical and epidemiological problems. This study established a rapid and accurate method for detection of MRSA in clinical samples. The MRSA detection procedure involved a magnetic separation technique and Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), and the characteristic peaks of proteins were compared to achieve the detection of MRSA. We treated PBS, blood and cerebrospinal fluid with MRSA, and identified it after short-term culture. The time and detection limit for identifying MRSA were determined. At the same time, we used the method to detect different proportions of mixed bacteria. The results revealed that the enrichment efficiency of Amp-MBs for MRSA in PBS, blood and cerebrospinal fluid was greater than 95 %, 80.95 % and 83.6 %, respectively. The whole detection process could be completed within 1.5 h. The negative and positive percent agreement of MRSA detection were 83 % and 95 %, respectively. In mixed bacterial samples, bacteria can be detected when the proportion of MRSA is greater than 50 %. Overall, this study provides an effective method for bacterial preconcentration and detection, which has high potential for rapid and sensitive diagnosis of MRSA infection

Magnetic Pd–Fe nanoparticles for sustainable Suzuki–Miyaura cross-coupling reactions

The development of palladium-catalyzed cross-coupling reactions has been revolutionized by bimetallic co-catalysis and magnetic separation techniques, which address the dual challenges of reducing the reliance on palladium (Pd) and advancing sustainable chemistry practices.

SPIONs Magnetophoresis and Separation via Permanent Magnets: Biomedical and Environmental Applications

Superparamagnetic iron oxide nanoparticles (SPIONs) have emerged as cutting-edge materials, garnering increasing attention in recent years within the fields of chemical and biomedical engineering. This increasing interest is primarily attributed to the distinctive chemical and physical properties of SPIONs. Progress in nanotechnology and particle synthesis methodologies has facilitated the fabrication of SPIONs with precise control over parameters such as composition, size, shape, stability, and magnetic response. Notably, these functionalized materials exhibit a remarkable surface-area-to-volume ratio, biocompatibility, and, most importantly, they can be effectively manipulated using external magnetic fields. Due to these exceptional properties, SPIONs have found widespread utility in the medical field for targeted drug delivery and cell separation, as well as in the chemical engineering field, particularly in wastewater treatment. Magnetic separation techniques driven by magnetophoresis have proven to be highly efficient, encompassing both high-gradient magnetic separation (HGMS) and low-gradient magnetic separation (LGMS). This review aims to provide an in-depth exploration of magnetic field gradient separation techniques, alongside a comprehensive discussion of the applications of SPIONs in the context of drug delivery, cell separation, and environmental remediation.

Mitochondrial Dysfunction after Repeated Mild Blast Traumatic Brain Injury Is Attenuated by a Mild Mitochondrial Uncoupling Prodrug.

Mild traumatic brain injury (mTBI) results in impairment of brain metabolism, which is propagated by mitochondrial dysfunction in the brain. Mitochondrial dysfunction has been identified as a pathobiological therapeutic target to quell cellular dyshomeostasis. Further, therapeutic approaches targeting mitochondrial impairments, such as mild mitochondrial uncoupling, have been shown to alleviate behavioral alterations after TBI. To examine how mild mitochondrial uncoupling modulates acute mitochondrial outcomes in a military-relevant model of mTBI, we utilized repeated blast overpressure of 11 psi peak overpressure to model repeated mild blast traumatic brain injury (rmbTBI) in rats followed by assessment of mitochondrial respiration and mitochondrial-related oxidative damage at 2 days post-rmbTBI. Treatment groups were administered 8 or 80 mg/kg MP201, a prodrug of 2,4 dinitrophenol (DNP) that displays improved pharmacokinetics compared with its metabolized form. Synaptic and glia-enriched mitochondria were isolated using fractionated a mitochondrial magnetic separation technique. There was a consistent physiological response, decreased heart rate, following mbTBI among experimental groups. Although there was a lack of injury effect in mitochondrial respiration of glia-enriched mitochondria, there were impairments in mitochondrial respiration in synaptic mitochondria isolated from the prefrontal cortex (PFC) and the amygdala/entorhinal/piriform cortex (AEP) region. Impairments in synaptic mitochondrial respiration were rescued by oral 80 mg/kg MP201 treatment after rmbTBI, which may be facilitated by increases in complex II and complex IV activity. Mitochondrial oxidative damage in glia-enriched mitochondria was increased in the PFC and hippocampus after rmbTBI. MP201 treatment alleviated elevated glia-enriched mitochondrial oxidative damage following rmbTBI. However, there was a lack of injury-associated differences in oxidative damage in synaptic mitochondria. Overall, our report demonstrates that rmbTBI results in mitochondrial impairment diffusely throughout the brain and mild mitochondrial uncoupling can restore mitochondrial bioenergetics and oxidative balance.

Recovering cobalt from cobalt oxide ore using suspension roasting and magnetic separation technique

Cobalt ore is a scarce resource in China, often associated with iron ore, and it is well known that its separation and effective recovery are extremely difficult. In this paper, cobalt oxide ore is used as raw material and reduced by suspension roasting method at the atmosphere of H2. Magnetic separation is carried out to obtain cobalt (Co) and Fe concentrate. The experimental results show that the optimal magnetic separation performance of cobalt oxide ore is achieved at 650 °C and 30 % H2 concentration. The Co and Fe concentration are obtained synchronously with the grade of 7.32 % and 62.13 % respectively. X-ray diffraction (XRD) and scanning electron microscope (SEM) reveals that the phase of cobalt oxide ore in H2 roasting process is transformed into CoO→Co and Fe2O3→Fe3O4. The surface of the sample appears cracks after roasting. The vibrating sample magnetometer (VSM) test reflects the magnetic changes of minerals that the optimum roasting condition leads to an increased magnetism. The specific surface and fracture structure are analyzed to illustrate the specific surface area and pore volume of the particles decrease and the average pore size increases as the roasting temperature increases. In general, reduction roasting of cobalt ore makes it possible to recover Co and Fe simultaneously, following by magnetic separation. The beneficiation efficiency is improved along with the reduced cost.

A novel magneto-mediated electrochemical biosensor integrated DNAzyme motor and hollow nanobox-like Pt@Ni–Co electrocatalyst as dual signal amplifiers for vanilla detection

Herein, a novel magneto-mediated electrochemical aptasensor using the signal amplification technologies of DNAzyme motor and electrocatalyst for vanilla (VAN) detection was fabricated. The D/B duplex, formed by the DNAzyme motor that was each silenced by a blocker, and hairpin DNA1 (H1) containing adenosine ribonucleotide (rA) site were tethered on the sites of the gold nanoparticles@hollow porphyrinic-Metal-organic framework/polyethyleneimine-reduced graphene oxide (AuHPCN-222/PEI-rGO)-modified gold electrode (AuE). Then, after homogeneous and specific recognition in the presence of the VAN, trigger DNA was released and enriched by magnetic separation technique and introduced to the sensing platform to activate the DNAzyme motor, which efficiently improved target recognition capability and avoided the obstacle of multiple DNA strands tangling. More interestingly, the activated DNAzyme motor could repeatedly bind to and cleave H1 in the presence of Mg2+, leading to the exposure of a plethora of capture probes. The thionine (Thi) functionalized hairpin DNA2 (H2)–Pt@Ni–Co as signal probes could hybridize with capture probes. Additionally, the Pt@Ni–Co electrocatalysts presented catalytic activity towards Thi to obtain stronger electrochemical signals. VAN with concentrations ranging from 1 × 10−6 to 10 μM was determined and a detection limit was down to 0.15 pM. The designed electrochemical sensor was highly selective with specificity, stability, reproducibility, and reliable capability for monitoring the VAN in real samples.

All-in-One Microfluidic Chip for Online Labeling, Separating, and Focusing Rare Circulating Tumor Cells from Blood Samples Followed by Inductively Coupled Plasma Mass Spectrometry Detection.

Circulating tumor cell (CTC) detection is essential for early cancer diagnosis and evaluating treatment efficacy. Despite the growing interest in isolating CTCs and further quantifying surface biomarkers at the single-cell level, highly efficient separation of rare CTCs from massive blood cells is still a big challenge. Here, we developed an all-in-one microfluidic chip system for the immunolabeling, magnetic separation, and focusing of HepG2 cells (as a CTC model) and online combined it with single cell-inductively coupled plasma mass spectrometry (SC-ICP-MS) for quantitative analysis of the asialoglycoprotein receptor (ASGPR) on single HepG2 cells. Lanthanide-labeled anti-ASGPR monoclonal antibody and antiepithelial cell adhesion molecule-modified magnetic beads were prepared as signal and magnetic probes, respectively. Target cells were highly efficiently labeled with signal and magnetic probes in the mixing zone of the microfluidic chip and then focused and sorted in the separation zone by specific magnetic separation techniques to avoid matrix contamination. The average cell recovery of HepG2 cells was derived to be 94.1 ± 5.7% with high separation efficiency and purity. The sorted cells with signal probes were detected for enumeration and quantification of ASGPR on their surface by SC-ICP-MS. The developed method showed good specificity and high sensitivity, detecting an average of (1.0 ± 0.2) × 105 ASGPR molecules per cell surface. This method can be used for absolute quantitative analysis of ASGPR on the surface of single hepatocellular carcinoma cells in real-world samples, providing a highly efficient analytical platform for studying targeted drug delivery in cancer therapy.

In situ construction of Fe3O4@PDA@Au multi hotspot SERS probe for trace detection of benzodiazepines in serum

The abuse of benzodiazepines is a serious health hazard that can cause damage to the central nervous system.Trace monitoring of benzodiazepines in serum can effectively prevent the damage caused by these drugs. Therefore, in this study, a Fe3O4@PDA@Au core–shell satellite nanomaterial SERS(Surface-Enhanced Raman Scattering) probe that integrates magnetic separation techniques and a multi-hotspot structure was synthetized by in situ growth of gold nanoparticles on the surface of PDA(Polymerized dopamine)-coated Fe3O4. The size and gap of Au nanoparticles on the surface of the SERS probe can be modulated by regulating the amount of HAuCl4 to create 3D multi-hotspot structures. The good dispersion and superparamagnetic properties of this SERS probe enable it to fully contact and load the target molecules in the serum, and the applied magnetic field facilitates separation and enrichment.This process increases the molecular density and number of SERS hotspots, thereby enhancing detection sensitivity. Based on the above considerations, this SERS probe can detect traces of eszopiclone and diazepam in serum at concentrations as low as 1 μg/ml with good linearity, offering promising applications in clinical monitoring of drug concentrations in blood.

An Overview of Precious Metal Recovery from Steel Industry Slag: Recovery Strategy and Utilization

Steel slag is a solid waste of the steel industry, produced during steel production. Three types of slag, namely electric arc furnace (EAF), basic oxygen furnace (BOF), and Linz-Donawitz processed slag (LD-slag) are the steel industry byproducts. That slag comprises precious elements including zinc (Zn), chromium (Cr), iron (Fe), nickel (Ni), silicon (Si) , aluminum (Al), and vanadium (V) and is considered a secondary source of many metals. These metal constituents can be recovered from slags by employing mineral processing techniques like crushing, grinding, magnetic separation, eddy current separation, flotation, leaching, and/or roasting. Metal extraction from steelmaking slag and slag utilization is essential not only for conserving metal supplies but also for environmental protection. This review article evaluated and summarized various extraction methods including magnetic separation, roasting, pyrometallurgical method, hydrometallurgical and bio hydrometallurgical technique to recover precious metal constituents from obtained slag. The state-of-the-art of metal recovery from slag using the aforementioned methodologies and the merits, and demerits of each procedure have been illustrated comprehensively. Suggestions have been made to overcome the shortfall and or lacuna of the technology for better performance and efficiency. The opportunities and difficulties portion of this article paints a vivid picture of turning such a beneficial technology into a more adaptable procedure with some additions that may motivate and lead future research in new directions. The essence of this survey indicates that extracted metal and treated slag might be reutilized in various fields ranging from biomedical to fertilizer applications.

Upgrading silica rock quality by using attrition scrubbing and magnetic separation techniques

The study was carried out to produce high-purity silica sand used for glass making. Generally, all grades of silica sands are comparable in their chemical composition except for iron oxide (Fe2O3) content, which is slightly rigid and its concentration varies for different applications. The objective of this work was to increase silicon dioxide (SiO2) content to at least 99.5% and to reduce iron oxide content to less than 0.015% using attrition scrubbing and magnetic separator technique for the purification process. Gravimetric analysis was carried out on the original sample to determine SiO2 content, and minor elements of Fe2O3 quantification using ultraviolet–visible (UV–VIS). A complete chemical and phase analysis were carried out on the raw sample and post-treatment samples. Field Emission Scanning Electron Microscopy (FESEM) was also employed for morphological and mineral phase identification. In this analysis, 70% of solid percent in pulp was used. The optimization of the scrubbing process was performed by studying the effect of using distilled water and citric acid at various concentrations of 0.25 M, 0.5 M, and 0.75 M. The processing time and rotational speed were kept constant at 20 min and 1250 rpm, respectively. The scrubbed silica rocks were then deslimed and dried before being subjected to a wet high intensity magnetic separator (WHIMS) with a magnetic field intensity of 3A, 5A, and 7A. According to this research work, more than 99.5% of SiO2 content and less than 0.015% of Fe2O3 content was achieved although using only distilled water in the scrubbing process. The optimum consumption of citric acid was 0.5 M in the acidic scrubbing process.

Recycling of siliceous by-products to reduce their impacts on the environment

Currently, there is a tendency to use less silica rich ores given the depletion of high-quality resources. The raw kaolin treatment of Tamazert (Eastern Algeria) produces, by hydrocyclone process, approximately 80 % of siliceous by-products. These siliceous wastes, which are stored in the open air, constitute a significant environmental problem. This research work aims to improve the quality of siliceous by-products, more particularly, to a process for the elimination of iron oxides and aluminum to make this raw material usable industrially as well as solving environmental issues. The collected by-products, were characterized by different techniques, such as X-ray fluorescence (XRF) and X-ray diffraction (XRD). XRF confirmed that the by-products east siliceous, with content going up to 82 % of SiO2. The by-product resulted from the raw kaolin treatment, mainly contains varying amounts of impurities such as iron oxide, titanium oxide and alumina. In all cases, the presence of these impurities affects the color and the physical properties of the mineral, and so lowers the economic value and limits the industrial application. In this framework, the classified fraction (–500)–(+100) µm was directed to attrition scrubbing followed by magnetic separation technique and chemical treatment by sulphuric acid with different concentrations. The results of the beneficiation tests of by-product indicate that using the attrition scrubbing alone not provides a suitable product for glass manufacture. The magnetic separation was tested with attrition on the useful fraction ((–500)–(+100) μm). The non-magnetic attritional fraction concentrates less than 0.45 % of Al2O3 and 0.05 % of Fe2O3. This low content coupled with a remarkable percentage in silica of 97.98 %.The tests by attrition and leaching with 40 % of sulphuric acid show, on the one hand, significant results with a high percentage of silica (>98.5 %) against 0.04 % Fe2O3 and 0.66 % Al2O3 ,and on the other hand, that the enriched product meets the standards required by glass making.

An electrochemical and colorimetric dual-mode aptasensor for Staphylococcus aureus based on a multifunctional MOF and magnetic separation technique

Staphylococcus aureus (S. aureus) is a widespread pathogenic bacterium, causing foodborne disease and posing threat to public safety. Thus, it is of great importance for rapid and effective determination of S. aureus. In this protocol, we synthesized a smart DNA-modified Au/CuMOF bioconjugate material (ssDNA-Au/CuMOF) with multiple functions of biorecognition, electrochemical and catalytical activity, and explored its application in dual-mode determination of S. aureus. Magnetic bead (MB) modified with aptamers (MB-Apt) was employed for specific S. aureus capture. The incubation of ssDNA-Au/CuMOF and MB-Apt with different concentration of S. aureus led to the difference in quantity of ssDNA-Au/CuMOF confined on MB or released in supernatant. After magnetic separation, dual-mode detection was realized by the electrochemical measurement and the material-catalyzed colorimetry. This method demonstrated a satisfied analytical performance with a broad linear range from 10 to 108 CFU mL−1, a colorimetric minimum resolution as low as 48 CFU mL−1, an electrochemical detection limit of 5 CFU mL−1, and good selectivity in distinguishing target from non-target bacteria. Its application in detecting S. aureus in complex samples also showed good response, indicating the great potential for S. aureus detection in real samples and providing a methodological and technical support for food monitoring.

Simultaneous Detection of Ovarian Cancer-Concerned HE4 and CA125 Markers Based on Cu Single-Atom-Triggered CdS QDs and Eu MOF@Isoluminol ECL.

Simultaneous detection of different disease markers is significant for clinical diagnosis. In this work, a dual-signal electrochemiluminescence (ECL) immunosensor was constructed for the simultaneous detection of carbohydrate antigen 125 (CA125) and human epithelial protein 4 (HE4) markers of ovarian cancer. The results showed that the Eu metal-organic framework-loaded isoluminol-Au nanoparticles (Eu MOF@Isolu-Au NPs) could generate a strong anodic ECL signal through synergistic interaction; as cathodic luminophore, the composite of carboxyl-functionalized CdS quantum dots and N-doped porous carbon-anchored Cu single-atom catalyst could catalyze H2O2 co-reactant to produce a large amount of •OH and O2•-, making the anodic and cathodic ECL signals significantly increase and become stable. Based on the enhancement strategy, a sandwich immunosensor was constructed for the simultaneous detection of ovarian cancer-associated CA125 and HE4 markers by combining antigen-antibody specific recognition and magnetic separation technique. The resulting ECL immunosensor displayed high sensitivity, a wide linear response range of 0.005∼500 ng mL-1, and low detection limits of 0.37 and 1.58 pg mL-1 for CA125 and HE4, respectively. Furthermore, it had excellent selectivity, stability, and practicability in the detection of real serum samples. This work establishes a framework for in-depth design and application of single-atom catalysis in ECL sensing.