Magnetic-Nanowaxberry-Based Simultaneous Detection of Exosome and Exosomal Proteins for the Intelligent Diagnosis of Cancer.

Exosome concentration and exosomal proteins are regarded as promising cancer biomarkers. Herein, a waxberry-like magnetic bead (magnetic-nanowaxberry) which has huge surface area and strong affinity was synthesized to couple with aptamer for exosome capture and recovery. Subsequently, we developed a fluorescent assay for the sensitive, accurate, and simultaneous quantification of exosome and cancer-related exosomal proteins [epidermal growth factor receptor (EGFR) and epithelial cell adhesion molecule (EpCAM)] by using triple-colored probes to recognize EGFR and EpCAM or spontaneously anchor to the lipid bilayer. In this design, the interference of soluble proteins can be avoided due to the dual recognition strategy. Moreover, the lipid-based quantification of exosome concentration can improve the accuracy. Besides, the simultaneous detection mode can save samples and simplify the operation steps. Consequently, the assay shows high sensitivity (the limits of detection are down to 0.96 pg/mL for EGFR, 0.19 pg/mL for EpCAM, and 2.4 × 104 particles/µL for exosome), high specificity, and satisfactory accuracy. More importantly, this technique is successfully used to analyze exosomes in plasma to distinguish cancer patients from healthy individuals. To improve the diagnostic efficacy, the deep learning was used to exploit the potential pattern hidden in data obtained by the proposed method. Also, the accuracy for the intelligent diagnosis of cancer can achieve 96.0%. This study provides a new avenue for developing new biosensors for exosome analysis and intelligent disease diagnosis.

In situ detection of plasma exosomal microRNA for lung cancer diagnosis using duplex-specific nuclease and MoS2 nanosheets.

MicroRNAs (miRNAs) encapsulated in tumor-derived exosomes are becoming ideal biomarkers for the early diagnosis and prognosis of lung cancer. However, the accuracy and sensitivity are often hampered by the extraction process of exosomal miRNA using traditional methods. Herein, this study developed a fluorogenic quantitative detection method for exosomal miRNA using the fluorescence quenching properties of molybdenum disulfide (MoS2) nanosheets and the enzyme-assisted signal amplification properties of duplex-specific nuclease (DSN). First, a fluorescently-labeled nucleic acid probe was used to hybridize the target miRNA to form a DNA/RNA hybrid structure. Under the action of the DSN, the DNA single strand in the DNA/RNA hybrid strand was selectively digested into smaller oligonucleotide fragments. At the same time, the released miRNA target triggers the next reaction cycle, so as to achieve signal amplification. Then, MoS2 was used to selectively quench the fluorescence of the undigested probe leaving the fluorescent signal of the fluorescently-labeled probe fragments. The fluorometric signals for miRNA-21 had a maximum excitation/emission wavelength of 488/518 nm. Most importantly, the biosensor was then applied for the accurate quantitative detection of miRNA-21 in exosome lysates extracted from human plasma and this method was able to successfully distinguish lung cancer patients from healthy people. This biosensor provides a simple, rapid, and a highly specific quantitative method for exosomal miRNA and has promising potential to be used in the early diagnosis of lung cancer.

Preparation of molecularly imprinted resin/polydopamine nanofibers mat for the highly efficient extraction and determination of sulfonamides in environmental water.

With polyacrylonitrile nanofibers mat (PAN NFsM) as a template, molecularly imprinted resin/polydopamine nanofibers mat (MIR/PDA NFsM) was synthesized for the extraction of sulfonamides (SAs) in water. The specific surface area and pore volume were increased obviously due to the functionalization of MIR. The adsorption efficiencies of MIR/PDA NFsM under optimized conditions for SAs were 92.3-99.3%. Possible adsorption mechanisms of imprinting recognition and hydrogen bond interactions were also put forward. Compared with MIR particles, the MIR/PDA NFsM exhibited much superior adsorption performance. Particularly, the outstanding mass transfer efficiency of MIR/PDA NFsM was much higher than the other reported adsorbents for SAs. Finally, a new method based on the solid-phase extraction (SPE) of MIR/PDA NFsM was successfully developed for the detection of five SAs in environmental water with HPLC-MS/MS and applied to the analysis of actual samples. Under the selected conditions, the enrichment factors of MIR/PDA NFsM of SCP, SMT, SMZ, SMR, and SMX were between 23.0 and 25.0. Low detection limits (0.26-0.76 ng L-1), broad linear range (1.0 ng L-1 to 10.0 µg L-1), and satisfactory recoveries (82.8-115.6%) and precisions (RSDs < 7.2%) were obtained. Moreover, the excellent reusability properties and storage stability endowed MIR/PDA NFsM with great value for practical applications.

The association between soy-based food and soy isoflavone intake and the risk of gastric cancer: a systematic review and meta-analysis.

Soy contains many bioactive phytochemicals, such as isoflavones, which have the effect of preventing many cancers. Some studies have shown the beneficial effect of soy-based food and isoflavone intake on gastric cancer (GC), while others claimed no effect. Therefore, whether the beneficial effect of soy-based food is related to its fermentation or whether its protective effect comes from isoflavones still remains inconclusive. Our aim was to investigate the relationship between total soybean, fermented soybean, non-fermented soybean and isoflavone intake, and the risk of GC. Ten cohort studies and 21 case-control studies involving 916 354 participants were included. The association between soy-based food and isoflavone intake and the risk of GC was calculated with the pooled relative risks (RRs) for the highest versus lowest intake categories. The results showed that isoflavone intake might be a protective factor to GC, but the result was not statistically significant (RR = 0.92; 95% CI: 0.79-1.07). However, total soybean intake could significantly decrease the risk of GC by 36% (RR = 0.64; 95% CI: 0.51-0.80), which might be credited to non-fermented soybean products (RR = 0.79; 95% CI: 0.71-0.87). In contrast, high intake of fermented soybean products could increase the risk of GC (RR = 1.19; 95% CI: 1.02-1.38). High intake of total soybean and non-fermented soybean products could reduce the risk of GC, and high intake of fermented soybean products could increase the risk, which indicated that the beneficial effect of soy-based food might be related to its non-fermentation. However, high intake of isoflavones may not be associated with the incidence of GC. © 2021 Society of Chemical Industry.

Fluorometric immunoassay for the simultaneous determination of the tumor markers carcinoembryonic antigen and cytokeratin 19 fragment using two kinds of CdSe/ZnS quantum dot nanobeads and magnetic beads.

A method is described for the simultaneous determination of the carcinoembryonic antigen (CEA) and cytokeratin 19 fragment (CYFRA21-1). Two kinds of CdSe/ZnS quantum dot nanobeads (QBs), with emission maxima at 530 nm (green) and 585 nm (yellow), were used as labels, and magnetic beads (MBs) for separation. The MBs were used as substrates to couple CEA and CYFRA21-1 antibody for isolating the proteins. Then, the differently colored QBs were linked to the antibodies against CEA and CYFRA21-1, respectively. Following the formation of the immunocomplex, the intensities of the green and yellow emissions were measured at the same excitation wavelength of 340 nm. The detection limits are 0.1 ng⋅mL- 1 for CEA, and of 0.2 ng⋅mL- 1 for CYFRA21-1. The recoveries from spiked serum are 92.1 - 118.1% for CEA, and from 90.8% to 115.2% for CYFRA21-1, with the relative standard deviations of 6.3 - 12.3% and 7.1 - 11.8%. The method was successfully applied to the simultaneous determination of the two proteins in human serum sample (n = 45). The results correlated well with those of the chemiluminescent enzyme immunoassay kit. Graphical AbstractSchematic presentation of the fluorescence immunoassay for the simultaneous determination of carcinoembryonic antigen (CEA) and cytokeratin 19 fragment (CYFRA21-1) based on quantum dot nanobeads (QBs) and magnetic beads (MBs) is reported. The intensities of two kinds of CdSe/ZnS QBs, with the emission maxima at 530 nm (green) and 585 nm (yellow) were measured at the same excitation wavelength of 340 nm.

Magnetism and electronic properties of ConMoP (n = 1 ~ 5) cluster: a DFT study.

CONTEXT: Hydrogen has emerged as a promising clean energy carrier, underscoring the imperative need to comprehend its adsorption mechanisms. This study delves into the magnetic and electronic properties of Co-Mo-P clusters, aiming to unveil their catalytic potential in hydrogen production. Employing density functional theory (DFT), we optimized cluster configurations and scrutinized their magnetic behaviors. Our investigation unveiled 16 stable configurations of the ConMoP (n = 1 ~ 5) cluster, predominantly in steric forms. The magnetic attributes were primarily ascribed to the d orbitals of Co metal atoms, with Co3MoP exhibiting exceptional magnetic characteristics. Analysis of density of state diagrams revealed the prevalence of spin-up α-electrons in d orbitals, while spin-down ß-electrons attenuated overall magnetic properties. Localized orbital (LOL) analysis highlighted stable covalent bonds within the clusters, affirming their catalytic potential. Orbital delocalization index (ODI) analysis revealed diverse spatial distribution ranges for orbitals across different configurations, suggesting a progressive attenuation of off-domain properties with increasing cluster size. Furthermore, infrared spectroscopy unveiled distinct vibrational peaks in various configurations, indicative of unique infrared activities. These findings contribute to a nuanced theoretical understanding of Co-Mo-P clusters and pave the path for future research aimed at augmenting their catalytic efficiency in hydrogen production. This study underscores the viability of Co-Mo-P clusters as alternatives to conventional Pt catalysts, offering insights into the design of novel materials for sustainable energy applications. Further research is warranted to explore the behavior of the Co-Mo-P system under diverse reaction conditions, fostering advancements in materials and energy science. METHODS: In this study, we harnessed the ConMoP (n = 1 ~ 5) cluster as a simulation platform for probing the local structure of the material. Our aim was to scrutinize the magnetism, electronic characteristics influenced by the varying metal atoms within these clusters. A systematic exploration involved incrementing the number of metal atoms and expanding the cluster size to elucidate the corresponding property variations. Density functional theory (DFT) calculations were pivotal to our methodology, employing the B3LYP hybrid functional implemented in the Gaussian 16 software package. The ConMoP (n = 1 ~ 5) cluster underwent optimization calculations and vibrational analysis at the def2-tzvp quantization level, yielding optimized configurations with diverse spin multiplet degrees. To comprehensively characterize and visually represent the stability, electronic features, and catalytic attributes of these configurations, we employed a suite of computational tools. Specifically, quantum chemistry software GaussView and wave function analysis software Multiwfn played integral roles. Through the integrated use of these computational tools, we acquired valuable insights into the magnetism, electronic characteristics of the ConMoP (n = 1 ~ 5) cluster, shedding light on their dependency on distinct metal atoms.

Simple, fast and eco-friendly micro-solid phase extraction based on thiol and ionic liquid bi-functional nanofibers membrane for the determination of sulfonamides in environmental water.

BACKGROUND: Sulfonamides (SAs) are a class of synthetic antibacterial agents that are diffusely used in the medical industry and animal husbandry. Their prevalence in the influents and effluents of water treatment plants, as well as in rivers and groundwater, has provoked worldwide concern. Monitoring SAs in environmental water is of great significance for public health. However, most of the available detection techniques for SAs are cumbersome and time-consuming. With the increasing number of actual samples, simple, fast and environmentally friendly analytical methods are always in demand. RESULTS: Herein, we describe a highly efficient micro-solid phase extraction (µ-SPE) sample preparation technique based on a novel thiol and ionic liquid bi-functional nanofibers membrane (IL-SH-PAN NFsM) for multi-residue detection of sulfonamides (SAs) in water samples. By the synergistic effect of -SH and -IL, the as-prepared IL-SH-PAN NFsM demonstrated high adsorption capacity and excellent selectivity for SAs. The water samples can be directly used for µ-SPE without pH and ionic strength adjustment, and the eluent can be directly collected for HPLC-MS/MS analysis. Compared with other methods reported in the literature, this method required much shorter extraction time (2 min for a batch), much less amount of adsorbent (4.0 mg) and organic solvent (0.5 mL), while providing much higher sensitivity (1.4-3.9 ng L-1), and fine recoveries (88.8%-117.7%) with relative standard deviations less than 4.26%. SIGNIFICANCE AND NOVELTY: A bi-functional nanofibers membrane was prepared for efficient extraction of SAs. The adsorbent exhibited superior adsorption performance and excellent selectivity. The underlying interaction mechanisms derived from -SH and -IL were proposed, which provide a new idea for preparing versatile adsorbents. Rapid, efficient and sensitive detection of SAs in water was achieved. The novel sample preparation technique can be expected as an efficient method for routine trace SAs residue monitoring in various water samples.

Self-assembly of cascade nanoenzyme glucose oxidase encapsulated in copper benzenedicarboxylate for wearable sweat-glucose colorimetric sensors with smartphone readout.

BACKGROUND: With the advent of personalized medical approaches, precise and tailored treatments are expected to become widely accepted for the prevention and treatment of diabetes. Paper-based colorimetric sensors that function in combination with smartphones have been rapidly developed in recent years because it does not require additional equipment and is inexpensive and easy to perform. In this study, we developed a portable, low-cost, and wearable sweat-glucose detection device for in situ detection. RESULTS: The sensor adopted an integrated biomimetic nanoenzyme of glucose oxidase (GOx) encapsulated in copper 1, 4-benzenedicarboxylate (CuBDC) (GOx@CuBDC) through a biomimetic mineralization process. CuBDC exhibited a peroxide-like effect, cascade catalytic effect with the encapsulated GOx, and increased the enzyme stability. GOx@CuBDC and 3,3,5,5-tetramethylbenzidine were combined to form a hybrid membrane that achieved single-step paper-based glucose detection. SIGNIFICANCE AND NOVELTY: This GOx@CuBDC-based colorimetric glucose sensor was used to quantitatively analyze the sweat-glucose concentration with smartphone readings. The sensor exhibited a good linear relationship over the concentration range of 40-900 µM and a limit of detection of 20.7 µM (S/N = 3). Moreover, the sensor performed well in situ monitoring and in evaluating variations based on the consumption of foods with different glycemic indices. Therefore, the fabricated wearable sweat-glucose sensors exhibited optimal practical application performance.

A signal-switchable photoelectrochemical biosensor for ultrasensitive detection of long non-coding RNA in cancer cells.

Long non-coding RNA (LncRNA) as an emerging tumor biomarker plays a key factor in the early diagnosis of cancer. Herein, an innovative signal-switchable photoelectrochemical (PEC) biosensor based on ZrO2@CuO bimetallic oxides and T7 Exo-assisted signal amplification is reported for the ultrasensitive and selective detection of lncRNA (HOX gene antisense intergenic RNA, HOTAIR) in cancer cells. Firstly, MOFs-derived TiO2 nanodisks as an excellent photoactive material show an anodic background signal. When target lncRNA exists, the abundant auxiliary DNA1 is freed from T7 Exo-assisted cycle signal amplification, and then competitively hybridizes with auxiliary DNA2 on the electrode. Subsequently, bimetallic MOFs-derived ZrO2@CuO octahedra with a high specific surface area and porous structure are introduced into TiO2 nanodisks-modified biosensor, which appears a cathodic photocurrent and achieves a switchable signal. The developed signal-switchable PEC biosensor shows ultrasensitive detection of lncRNA HOTAIR with a detection limit of 0.12 fM, and can eliminate the false interference. Importantly, the established PEC biosensor has good correlation with RT-qPCR analysis (P < 0.05) for the quantification of lncRNA HOTAIR in cancer cells, which has great potential application for biomarker detection in the early diagnosis of cancer.

Research progress of human key DNA and RNA methylation-related enzymes assay.

Gene methylation-related enzymes (GMREs) are disfunction and aberrantly expressed in a variety of cancers, such as lung, gastric, and pancreatic cancers and have important implications for human health. Therefore，it is critical for early diagnosis and therapy of tumor to develop strategies that allow rapid and sensitive quantitative and qualitative detection of GMREs. With the development of modern analytical techniques and the application of various biosensors, there are numerous methods have been developed for analysis of GMREs. Therefore, this paper provides a systematic review of the strategies for level and activity assay of various GMREs including methyltransferases and demethylase. The detection methods mainly involve immunohistochemistry, colorimetry, fluorescence, chemiluminescence, electrochemistry, etc. Then, this review also addresses the coordinated role of various detection probes, novel nanomaterials, and signal amplification methods. The aim is to highlight potential challenges in the present field, to expand the analytical application of GMREs detection strategies, and to meet the urgent need for future disease diagnosis and intervention.

Application of density functional theory to study the electronic structure and magnetic behavior of clusters MnPS3 (M = Fe, Co, Ni; n = 0 ~ 3).

CONTEXT: The article explores and compares the electronic structure and magnetic properties of transition metal phosphate materials, namely FePS3, CoPS3, and NiPS3. RESEARCH FINDINGS: Analysis of the optimized configuration reveals significant insights into the electronic properties of MnPS3 clusters. Electrons within the cluster exhibit a flow from the metal atom M and the non-metal atom P to the non-metal atom S. The S atom serves as the primary site for electrophilic reactions within the cluster, while the metal atom hosts the main site for nucleophilic reactions. Configurations 2a(2), 2b(2), 3a(4), 3b(3), and 3c(2) exhibit enhanced electron mobility and optimal electronic properties. Moreover, the analysis of the magnetic properties of the optimized configurations demonstrates that the magnetic behavior of MnPS3 clusters is influenced by the spin motion of α electrons in the p orbital. Metal atoms make a relatively significant contribution to the magnetic properties of MnPS3 clusters. Configurations 1b(3), 2c(4), and 3a(4) exhibit comparatively higher magnetic properties compared to other configurations of the same size. This study identifies the optimal configuration for the magnetic and electronic properties of transition metal phosphorothioate materials. It also elucidates the trends in magnetic and electronic properties as the number of metal atoms varies, thereby providing valuable theoretical support for the application of these materials in the fields of magnetic materials and electronic devices. METHODS: In this study, the Fe-based transition elements, namely Fe, Co, and Ni, are selected as the metal atoms M. The cluster MPS3 is used to simulate the local structure of the material, allowing for an investigation into the influence of the metal atoms on its electronic and magnetic properties. By increasing the number of metal atoms and expanding the cluster size, the variations in these properties are explored. Density functional theory (DFT) calculations are performed using the B3LYP functional within the Gaussian09 software package. The MnPS3 cluster is subjected to optimal calculations and vibrational analysis at the def2-tzvp quantization level, resulting in optimized configurations with different spin multiplet degrees. Quantum chemistry software GaussView, wave function analysis software Multiwfn, and plotting software Origin are utilized for data characterization and graphical representation of the magnetic and electronic properties of the optimized configurations. Through the employment of these computational tools, valuable insights into the magnetic and electronic properties of the MnPS3 cluster and its dependency on different metal atoms are obtained.

Density functional theory studies on properties of cluster ConMoS (n=1 ~ 5): interatomic interactions, electronic properties, frontier orbitals.

CONTEXT: To comprehend the microscopic property alterations within the ConMoS cluster (n=1-5), this study investigates its internal interactions, electronic characteristics, and orbital correlations employing density functional theory. Structural optimization and theoretical analysis of the cluster are conducted using the Gaussian09 software package, considering various spin multiplicities and employing the B3LYP/def2tzvp quantum chemical method as the computational standard. The outcomes reveal the optimization of the cluster, resulting in 21 stable configurations while continually acquiring energy from the external environment. Analysis of the interaction region indicator functions, the independent gradient model based on Hirshfeld partition, the localized orbital indicator functions, and the electron localization function reveals a trend toward chemical bonding interactions within the interatomic interaction regions. Moreover, the interatomic forces exhibit a high likelihood of engaging in covalent bonding interactions. Both Co and Mo atoms display greater electron delocalization, facilitating the exchange of electrons with the external environment. The paper discuss electron space range, hardness and softness, polarizability, dipole moment, Mulliken population analysis, density of states, HOMO-LUMO diagram, and UV-Vis spectra. Configuration 5a exhibits the broadest electron delocalization and the highest reactivity. It maintains structural stability in external conditions and displays the most polarized molecules. Metal atoms in this cluster exhibit superior mobility compared to non-metal atoms. We elucidate the electron density aggregation region within the cluster. Configuration 1a demonstrates the highest correlation with molar absorption coefficient for its peak. Analyzing the HOMO and LUMO orbital delocalization index and center-of-mass distances revealed that the front orbits of configuration 5a exhibited a broad distribution in space and the minimum center-of-mass distance. METHODS: This study presents a theoretical investigation of Co-Mo-S clusters employing density functional theory (DFT). DFT is a prevalent method for exploring the electronic structure and characteristics of atoms, molecules, and solids. The paper examines cluster attributes encompassing interatomic interactions, electronic properties, and frontier orbitals. Gaussian09 software is employed for optimizing cluster structures, while the analysis is augmented using Multiwfn wave function analysis software. By harnessing these theoretical and computational tools, it aims to delve deeper into cluster properties, yielding valuable insights.

Stability, electronic and catalytic properties of ConMoP(n = 1 ~ 5) clusters: A DFT study.

CONTEXT: The investigation of the stability, electronic properties, and catalytic activity of clusters ConMoP holds significant applications and implications in catalyst design, materials science, energy conversion and storage, and environmental protection. The study aims to delve into the unique features of the clusters ConMoP(n = 1 ~ 5), aiming to drive advancements in these related fields. The results obtained from the analysis revealed the stable configurations of the ten clusters, primarily characterized by steric structures. Furthermore, the energy of the clusters was found to increase continuously during growth, as indicated by calculations of atomic fragmentation energy and atomic binding energy. The researchers conducted an analysis of the Natural Population Analysis(NPA) charge, which revealed that Co atoms acted as electron donors, while P and Mo atoms acted as electron acceptors within the clusters. Additionally, an examination of the electrostatic potential indicated that Co and Mo atoms displayed nucleophilic tendencies, while P atoms exhibited electrophilic characteristics. Moreover, the density of states curves, HOMO and LUMO orbitals, and Kooperman's theorem were applied to the clusters ConMoP(n = 1 ~ 5).Through this study, a deeper understanding of the properties and behavior of clusters ConMoP has been achieved, shedding light on their potential as catalysts. The findings contribute to the existing knowledge of these clusters and provide a basis for further research and exploration in this field. METHODS: In this study, we employed the clusters ConMoP(n = 1 ~ 5) to simulate the local structure of the material, enabling us to investigate the stability, electronic properties, and catalytic properties influenced by the metal atoms. By systematically increasing the number of metal atoms and expanding the cluster size, we explored the variations in these properties. Density functional theory (DFT) calculations were performed using the B3LYP hybrid functional implemented in the Gaussian09 software package. The clusters ConMoP(n = 1 ~ 5) underwent optimization calculations and vibrational analysis at the def2-tzvp quantization level, resulting in optimized configurations with different spin multiplet degrees. For data characterization and graphical representation of the stability, electronic properties, and catalytic properties of the optimized configurations, we utilized a range of computational tools. Specifically, the quantum chemistry software GaussView, wave function analysis software Multiwfn were employed. Through the comprehensive utilization of these computational tools, we gained valuable insights into the stability, electronic properties, and catalytic properties of the clusters ConMoP(n = 1 ~ 5) and their dependence on different metal atoms.

Simple and efficient solid phase extraction based on molecularly imprinted resorcinol-formaldehyde resin nanofibers for determination of trace sulfonamides in animal-origin foods.

Novel molecularly imprinted resorcinol-formaldehyde resin nanofibers (MIRF NFs) was prepared using polydopamine as an intermediate. With high specific surface area and favorable usability, MIRF NFs presented high efficiency for the solid phase extraction (SPE) of sulfonamides (SAs) in complex animal foods. After optimizing the operating conditions, a new method for SAs quantification coupled with HPLC-MS/MS was developed. By simple water dilution of the solvent extracts, SPE could be carried out. In addition, the eluent could be analyzed directly without any further treatment. The newly developed method was simplified greatly with much fewer sample pretreatment procedures (4 steps). Moreover, much fewer amounts of sample (1.0 g), adsorbent (3.0 mg), organic solvent (1.5 mL) and preparation time (20 min for 24 samples) were needed. The obtained good linearity (R2 > 0.9957), low detection limits (0.01-0.14 µg kg-1), satisfactory recoveries (83.0 %-112.9 %) and precisions (RSDs < 12.6 %) further proved the feasibility of the method in practical application.

Comparative analysis of electronic, magnetic, catalytic properties of clusters (PS4, CrnPS4, AlnPS4, GanPS4, n = 1 ~ 3) based on density functional theory.

CONTEXT: The article presents a comparative study of the electronic, magnetic and catalytic properties of CrPS4, AlPS4, GaPS4 and their expanded structures. It is finally found that: When n = 2, 3, the internal electron mobility of the configurations is stronger than when n = 0,1. When n = 1, the five configurations, except configuration 1Cr(4), are susceptible to both electrophilic and nucleophilic reactions at the same time. The configurations are more prone to nucleophilic reactions when n = 2 and 3, and the reaction sites are mainly located on the metal atoms; the more metal atoms, the more nucleophilic reaction sites. When the M atoms in the configuration are Al and Ga atoms, there is no big difference between the contribution of metal atoms and non-metal atoms to the magnetism in the configuration, while in the configuration containing Cr atoms, the metal atoms contribute more to the magnetism and mainly originate from the d-orbitals, which has better magnetic properties and greater application value. Configuration 2Cr(4) and configuration 1Cr(2) have better catalytic and adsorption activities and are most suitable as catalysts. METHODS: In the article, based on topological principles, density functional theory, B3LYP functional and def2-tzvp basis group and Gaussian16 quantum chemistry software were used to optimise the calculations of the clusters CrPS4, AlPS4, GaPS4 and their expanded configurations, with the most stable structure selected for each cluster, and finally, with the help of Multiwfn program, the required analytical data were obtained by assisting the calculations.

Universal DNAzyme walkers-triggered CRISPR-Cas12a/Cas13a bioassay for the synchronous detection of two exosomal proteins and its application in intelligent diagnosis of cancer.

Exosomal proteins are considered to be promising indicators of cancer. Herein, a novel DNAzyme walkers-triggered CRISPR-Cas12a/Cas13a strategy was proposed for the synchronous determination of exosomal proteins: serum amyloid A-1 protein (SAA1) and coagulation factor V (FV). In this design, the paired antibodies were used to recognize targets, thereby ensuring the specificity. DNAzyme walkers were employed to convert the contents of SAA1 and FV into activators (P1 and P2), and one target can produce abundant activators, thus achieving an initial amplification of signal. Furthermore, the P1 and P2 can activate CRISPR-Cas12a/Cas13a system, which in turn trans-cleaves the reporters, enabling a second amplification and generating two fluorescent signals. The assay is highly sensitive (limits of detection as low as 30.00 pg/mL for SAA1 and 200.00 pg/mL for FV), highly specific and ideally accurate. More importantly, it is universal and can be used to detect both non-membrane and membrane proteins in exosome. Besides, the method can be successfully applied to detect SAA1 and FV in plasma exosomes to differentiate between lung cancer patients and healthy individuals. To explore the application of the developed method in tumor diagnosis, a deep learning model based on the expressions of SAA1 and FV was developed. The accuracy of this model can achieve 86.96%, which proves that it has a promising practical application capacity. Thus, this study does not only provide a new tool for the detection of exosomal proteins and cancer diagnosis, but also propose a new strategy to detect non-nucleic acid analytes for CRISPR-Cas system.

Fluorescent Sensor Based on Magnetic Separation and Strand Displacement Amplification for the Sensitive Detection of Ochratoxin A.

Ochratoxin A (OTA) is a common mycotoxin, and it is a significant threat to human health throughout the food chain. In this study, a sensitive and specific fluorescent sensor based on magnetic separation technology combined with chain displacement amplification was developed for fast and easy detection of OTA in food. The designed strand displacement amplification can improve the sensitivity for the detection, and the magnetic nanomaterials can provide a large surface area, thus enhancing the capture efficiency of the target from the sample. Based on those designs, the experimental results showed that the proposed method displayed excellent performance. The linearity range was 0.5-128.0 ng/mL. The detection limit was 0.125 ng/mL; the relative standard deviations were 3.92-7.71%. Additionally, the developed method was satisfactorily applied to determine OTA in wheat, corn, and red wine samples at three spiked levels (1.0, 8.0, and 64.0 ng/mL). The recoveries ranged from 85.45 to 107.8% for wheat flour, 101.34 to 108.35% for corn flour, and 91.15 to 93.80% for red wine, respectively. Compared with high-performance liquid chromatography, the proposed method showed a lower limit of detection and equal recovery. Hence, the designed method is a potential and good detecting tool for OTA residue analysis in complex matrix samples.

Correction to "Fluorescent Sensor Based on Magnetic Separation and Strand Displacement Amplification for the Sensitive Detection of Ochratoxin A".

[This corrects the article DOI: 10.1021/acsomega.3c01408.].

Fluorescence quenching determination of tetracyclines based on the synergistic oxidation effect between Fe3O4nanoparticles and tetracyclines.

In recent years, tetracyclines (TCs) is a hot research topic. Herein, we report an interesting discovery using the complexation of oxytetracycline and metal ions. In this study, according to the properties of Fe3O4nanoparticles (Fe3O4NPs) as a nanoenzyme, it can be used to catalyze the oxidation of KI by H2O2to produceI3-,while at the same timeI3-binds to rhodamine 6G (Rh6G) to form a conjoined particle (Rh6G ∼ I3)n, leading to a decrease in the fluorescence intensity of Rh6G. However, in the presence of TCs, Fe3O4NPs have a synergistic effect with TCs, leading to enhanced catalytic activity, as well as better selectivity compared to the activity of other reducing enzymes. Consequently,the fluorescent signal based on a resonance scattering effect between Rh6G andI3-is dependent on the concentration of TCs, thus achieving highly facile and robust detection of TCs. The limits of detection (LOD) of the method were 20 nM, 10 nM and 40 nM for oxytetracycline(OTC), tetracycline(TC) and chlortetracycline(CTC), respectively. Most importantly, the method can be successfully applied to the detection of TCs in milk, eggs, and honey. The recoveries of spiked samples ranged from 83.11 to 118.95%. Thus, a stable, hands-on strategy for the detection of TCs is proposed, which has potential applications in the field of food safety and environmental protection.