Magnetic Gold Nanoparticles Research Articles

Induced magnetic field and thermal regulation of synovial fluid flow through irregular surfaces with first-order slip and gold nanoparticles

ABSTRACT The current computational exploration develops a poroelastic model of the knee cartilage to elevate its temperature under cyclic sinusoidal loading. A contributing factor to the rise in temperature is this tissue’s viscous dissipation, which converts some of the mechanical energy supplied into heat. The manipulation of cartilage temperature is mostly reliant on the movement of synovial fluid inside the space between joints and within the permeable cartilage. We developed the region flow model in the presence of induced magnetic fields and gold nanoparticles, which enhanced the efficiency of joint lubrication by boosting the load-carrying capacity. We dealt with the problem for two different models. Model 1 assumes that viscosity is exponentially dependent on concentration. The shear thinning index in Model 2 is regarded as a concentration-dependent variable. We introduce these models for a complex wavy surface, where the first-order slip effect occurs. We modified the governing problem by assuming a long wavelength and a low Reynolds number. We followed up with a computational analysis utilizing the Rung–Kutta–Merson approach with Newton iteration in a shooting and matching strategy. We have conducted detailed comparisons between Model 1 and Model 2. The graphical findings have been shown for the distributions of velocity, temperature, and nanoparticle concentration. Additionally, the pressure gradients, streamlines, and axially generated magnetic fields have also been included. These results are presented for numerous physical parameters. The mechanics of trapping are thoroughly examined through the use of streamlines.

Ultrasensitive Electrochemiluminescence Biosensor Based on DNA-Bio-Bar-Code and Hybridization Chain Reaction Dual Signal Amplification for Exosomes Detection.

Exosomes have received considerable attention as potent reference markers for the diagnosis of various neoplasms due to their close and direct relationship with the proliferation, adhesion, and migration of tumor. The ultrasensitive detection of cancer-derived low-abundance exosomes is imperative, but still a great challenge. Herein, we report an electrochemiluminescence (ECL) biosensor based on the DNA-bio-bar-code and hybridization chain reaction (HCR)-mediated dual signal amplification for the ultrasensitive detection of cancer-derived exosomes. In this system, two types of aptamers were modified on the magnetic nanoprobe (MNPs) and gold nanoparticles (AuNPs) with numerous bio-bar-code DNA, respectively, which formed "sandwich" structures in the presence of specific target exosomes. The "sandwich" structures were separated under magnetic field, and the numerous bio-bar-code DNA were released by dissolving AuNPs. The released bio-bar-code DNA triggered the HCR procedure to produce a good deal of long DNA duplex structure for embedding in hemin, which generated strong ECL signal in the presence of coreactors for ultrasensitive detection of exosomes. Under the optimal conditions, it exhibited a good linearly of exosomes ranging from 10 to 104 exosomes particle μL-1 with limit of detection down to 5.01 exosome particle μL-1. Furthermore, the high ratio of ECL signal and minor change of ECL intensity indicated the good specificity, stability, and repeatability of this ECL biosensor. Given the good performance for exosome analysis, this ultrasensitive ECL biosensor has a promising application in the clinical diagnosis of early cancers.

A Lateral Flow Biosensor Based on Isothermal Amplification for Visual Identification of Species and Sex from Bloodstain.

The prompt species identification from biological samples at a crime scene can rapidly filter out truly valuable biometric information for subsequent personal identification. Meanwhile, early sex determination can assist in narrowing the pool of suspects. However, the current methods for forensic DNA analysis, particularly in point-of-care scenarios, are often limited by the intricate equipment for signal generation and the laborious procedure for DNA purification. The present study introduces a novel portable lateral flow biosensor that possesses extraction-free and anti-aerosol characteristics for on-site determination of species and sex. The bloodstain can be directly submitted to loop-mediated isothermal amplification (LAMP) for the analysis of both mitochondrial and nuclear DNA. The incorporation of a lateral flow device with gold magnetic nanoparticle probes allows for visual interpretation of results through colorimetric signals while also preventing interference on result judgment from pigments such as hemoglobin. Carryover contamination, which is a disharmonious factor in LAMP, especially as the inherent contradiction derived from uncapping in the lateral flow strategy, has been effectively addressed through the integration of uracil DNA glycosylase without compromising the isothermy throughout the process. As a proof-of-concept experiment, species and sex can be accurately identified within 40 min from trace bloodstains amidst significant background interference by targeting cytochrome b and Y-chromosomal amelogenin. Furthermore, the single-blind study revealed a concordance rate of up to 100% in both simulative degraded and true dated bloodstains. This suggests that this biosensor has the potential to be utilized in forensic DNA analysis at crime scenes.

Heteromultivalent DNA Enhances the Assembly Yield of Hybrid Nanoparticles and Facilitates Dynamic Disassembly for Bioanalysis Using ICP-MS.

To obtain enhanced physical and biological properties, various nanoparticles are typically assembled into hybrid nanoparticles through the binding of multiple homologous DNA strands to their complementary counterparts, commonly referred to as homomultivalent assembly. However, the poor binding affinity and limited controllability of homomultivalent disassembly restrict the assembly yield and dynamic functionality of the hybrid nanoparticles. To achieve a higher binding affinity and flexible assembly choice, we utilized the paired heteromultivalency DNA to construct hybrid nanoparticles and demonstrate their excellent assembly characteristics and dynamic applications. Specifically, through heteromultivalency, DNA-functionalized magnetic beads (MBs) and gold nanoparticles (AuNPs) were efficiently assembled. By utilizing ICP-MS, the assembly efficiency of AuNPs on MBs was directly monitored, enabling quantitative analysis and optimization of heteromultivalent binding events. As a result, the enhanced assembly yield is primarily attributed to the fact that heteromultivalency allows for the maximization of effective DNA probes on the surface of nanoparticles, eliminating steric hindrance interference. Subsequently, with external oligonucleotides as triggers, it was revealed that the disassembly mechanism of hybrid nanoparticles was initiated, which was based on an increased local concentration rather than toehold-mediated displacement of paired heteromultivalency DNA probes. Capitalizing on these features, an output platform was then established based on ICP-MS signals that several Boolean operations and analytical applications can be achieved by simply modifying the design sequences. The findings provide new insights into DNA biointerface interaction, with potential applications to complex logic operations and the construction of large DNA nanostructures.

Colorimetric aptasensor based on magnetic beads and gold nanoparticles for detecting mucin 1

In this work, a colorimetric aptasensor based on magnetic beads (MBs), gold nanoparticles (AuNPs) and Horseradish Peroxidase (HRP) was prepared for the detection of mucin 1 (MUC1). Complementary DNA of the MUC1 aptamer (Apt) immobilized on the MBs was combined with the prepared AuNPs-Apt-HRP complex (AuNPs@Apt-HRP). In the presence of MUC1, it specifically bound to Apt, resulting in the detachment of gold nanoparticles from the MBs. After magnetic separation, AuNPs@Apt-HRP was separated into the supernatant and reacted with 3,3′,5,5′-Tetramethylbenzidine (TMB) to produce color reaction from colorless to blue. The linear range of MUC1 was from 75 to 500 μg/mL (R2 = 0.9878), and the detection limit was 41.95 μg/mL. The recovery rate of MUC1 in human serum was 99.18 %∼101.15 %. This method is simple and convenient. Moreover, it does not require complex and expensive equipment for detection of MUC1. It provides value for the development of MUC1 colorimetric sensors and a promising strategy for the determination of MUC1 in clinical diagnosis.

Whole‐Cell Electrochemical Aptasensors for Cancer Diagnosis: Current Advances and Prospects

AbstractCancer is one of the most life‐threatening diseases worldwide. Numerous diagnostic and therapeutic techniques, such as nanomaterials‐based cancer detection and imaging‐guided focal therapy, are successfully developed to achieve highly precise cancer theranostic strategies. However, due to unpredictive alterations occurring in cancer cell morphology, a lack of sensitivity and selectivity is a critical challenge among most biomarkers’ detection. To address this issue, instead of targeting proteins or biomarkers, the detection of cancer using whole cell‐based biosensors are ubiquitously discovered through a selective oligonucleotide, so‐called aptamer. Aptamer‐based whole‐cell detection is concurrently engaged with various nanomaterials, such as magnetic beads, gold (Au) nanoparticles, and graphene family to establish a better performance of the biosensor. In this research review, the recent strategies and prospects on whole‐cell cancer detection platform based on electrochemical aptasensors integrated with nanomaterials are thoroughly discussed and summarized. Finally, future challenges and prospects are also provided.

Development of a Magnetically-Assisted SERS Biosensor for Rapid Bacterial Detection.

Ultrasensitive bacterial detection methods are crucial to ensuring accurate diagnosis and effective clinical monitoring, given the significant threat bacterial infections pose to human health. The aim of this study is to develop a biosensor with capabilities for broad-spectrum bacterial detection, rapid processing, and cost-effectiveness. A magnetically-assisted SERS biosensor was designed, employing wheat germ agglutinin (WGA) for broad-spectrum recognition and antibodies for specific capture. Gold nanostars (AuNSs) were sequentially modified with the Raman reporter molecules and WGA, creating a versatile SERS tag with high affinity for a diverse range of bacteria. Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) antibody-modified Fe3O4 magnetic gold nanoparticles (MGNPs) served as the capture probes. Target bacteria were captured by MGNPs and combined with SERS tags, forming a "sandwich" composite structure for bacterial detection. AuNSs, with a core size of 65 nm, exhibited excellent storage stability (RSD=5.6%) and demonstrated superior SERS enhancement compared to colloidal gold nanoparticles. Efficient binding of S. aureus and P. aeruginosa to MGNPs resulted in capture efficiencies of 89.13% and 85.31%, respectively. Under optimized conditions, the developed assay achieved a limit of detection (LOD) of 7 CFU/mL for S. aureus and 5 CFU/mL for P. aeruginosa. The bacterial concentration (10-106 CFU/mL) showed a strong linear correlation with the SERS intensity at 1331 cm-1. Additionally, high recoveries (84.8% - 118.0%) and low RSD (6.21% - 11.42%) were observed in spiked human urine samples. This study introduces a simple and innovative magnetically-assisted SERS biosensor for the sensitive and quantitative detection of S. aureus or P. aeruginosa, utilizing WGA and antibodies. The developed biosensor enhances the capabilities of the "sandwich" type SERS biosensor, offering a novel and effective platform for accurate and timely clinical diagnosis of bacterial infections.

CRISPR/Cas13a-assisted amplification-free miRNA biosensor via dark-field imaging and magnetic gold nanoparticles.

MicroRNAs (miRNAs) are short (about 18-24 nucleotides) non-coding RNAs and have emerged as potential biomarkers for various diseases, including cancers. Due to their short lengths, the specificity often becomes an issue in conventional amplification-based methods. Next-generation sequencing techniques could be an alternative, but the long analysis time and expensive costs make them less suitable for routine clinical diagnosis. Therefore, it is essential to develop a rapid, selective, and accurate miRNA detection assay using a simple, affordable system. In this work, we report a CRISPR/Cas13a-based miRNA biosensing using point-of-care dark-field (DF) imaging. We utilized magnetic-gold nanoparticle (MGNPs) complexes as signal probes, which consist of 200 nm-sized magnetic beads and 60 nm-sized gold nanoparticles (AuNPs) linked by DNA hybridization. Once the CRISPR/Cas13a system recognized the target miRNAs (miR-21-5p), the activated Cas13a cleaved the bridge linker containing RNA sequences, releasing 60 nm-AuNPs detected and quantified by a portable DF imaging system. The combination of CRISPR/Cas13a, MGNPs, and DF imaging demonstrated amplification-free detection of miR-21-5p within 30 min at a detection limit of 500 attomoles (25 pM) and with single-base specificity. The CRISPR/Cas13a-assisted MGNP-DF assay achieved rapid, selective, and accurate detection of miRNAs with simple equipment, thus providing a potential application for cancer diagnosis.

Orchestration of ferro- and anti-ferromagnetic ordering in gold nanoclusters.

The unpaired electron in the gold clusters (Aun, n = no. of Au atoms) with an odd number of total electrons is solely responsible for the magnetic properties in the small-sized Au nano-clusters. However, no such unpaired electron is available due to pairing in the even number of atom gold clusters and behaving as a diamagnetic entity similar to bulk gold. In this work, we unveiled the spin-density distribution of odd Aun clusters with n = 1 to 19 that reveals that a single unpaired electron gets distributed non-uniformly among all Au-atoms depending on the cluster size and morphology. The delocalization of the unpaired electron leads to the spin dilution approaching a value of ∼1/n spin moments on each atom for the higher clusters. Interestingly, small odd-numbered gold clusters possess spin-magnetic moments similar to the delocalized spin moments as of organic radicals. Can cooperative magnetic properties be obtained by coupling these individual magnetic gold nanoparticles? In this work, by applying state-of-the-art computational methodologies, we have demonstrated ferromagnetic or anti-ferromagnetic couplings between such magnetic nanoclusters upon designing suitable organic spacers. These findings will open up a new avenue of nanoscale magnetic materials combining organic spacers and odd-electron nano-clusters.

Multiple Isothermal Amplification Coupled with CRISPR-Cas14a for the Naked-eye and Colorimetric Detection of Aflatoxin B1.

Aflatoxin B1 (AFB1) is highly toxic and challenging to remove, posing significant risks to both human health and economic development. Therefore, there is an urgent need to develop rapid, simple, and sensitive detection technologies. In this study, we introduce a naked-eye and colorimetric method based on multiple isothermal amplifications coupled with CRISPR-Cas14a and investigate its biosensing properties. This technique utilizes composite nanoprobes (MAPs) comprising magnetic nanoparticles and gold nanoparticles. AFB1 is efficiently identified through an aptamer competition process facilitated by magnetic nanoparticles , which triggers multiple isothermal amplification. This converts trace amounts of the toxin into a large quantity of DNA signal. Upon specific activation of the CRISPR-Cas14a complex, the MAPs are cleaved, resulting in significant changes in both color and colorimetric signal. The method demonstrates acceptable sensitivity, with a detection limit of 31.90 pg mL-1 and a wide detection range from 0.05 to 10 ng mL-1. Furthermore, the assay exhibits satisfactory specificity and high accuracy when it is applied to practical samples. Our approach offers a universal sensing platform with potential applications in food safety, environmental monitoring, and clinical diagnostics.

Analysis of Correlation Between Coronary Heart Disease and Genetic Polymorphism Detected by Gold Magnetic Nanoparticles Chromatography.

It aimed to explore the correlation of Glu504Lys locus mutation of aldehyde dehydrogenase-2 (ALDH2) with coronary heart disease (CHD) based on gold magnetic nanoparticles (GMNPs) chromatography and amplification refractory mutation system-PCR (ARMS-PCR). 120 CHD patients admitted to the cardiovascular Department of Wenling First People's Hospital affiliated to Wenzhou Medical University from December 2020 to December 2021 were selected as Case group and 80 non-CHD patients admitted during the same period were selected as Ctrl group. The venous blood and indexes of Total Cholesterol (TC), Triglyceride (TG), Low Density Lipoprotein Cholesterol (LDL-C), High Density Lipoprotein Cholesterol (HDL-C), and Fasting Blood Glucose (FBS) were collected. The ARMS-PCR GMNPs chromatography based on ARMS-PCR and immunochromatography assay was adopted to detect gene polymorphism of ALDH2. Correlation between ALDH2 gene polymorphism and risk factors of CHD was analyzed via logistic regression. In contrast to Ctrl group, the genotypes of GG, GA, and AA in Case group were evidently different (P < 0.05), and the frequency of A allelic gene was obviously increased (P < 0.05). Under the dominant model, frequency of GA + AA genotype in Case group was remarkably higher in contrast to Ctrl group (P < 0.05). Under the recessive model, there was no obvious difference in genotype frequency between two groups. In contrast to Ctrl group, TC, LDL-C, and FBS in Case group were notably increased (P < 0.05), while HDL-C was notably decreased (P < 0.05). The distribution frequency of abnormal LDL-C, HDL-C, and FBS in Case group was notably higher in contrast to Ctrl group (P < 0.05). LDL-C and FBS had no obvious effect on the genotypes and frequency distribution of alleles in CHD patients. However, the frequency distribution of genotypes of GA and AA and A allelic gene in patients with abnormal HDL-C was notably lower in contrast to those with normal HDL-C (P < 0.05). Logistic regression analysis showed that abnormal HDC-C with A allelic gene were independent risk factors for CHD (P = 0.001, OR = 1.934). The gene polymorphism of Glu504Lys locus of ALDH2 was closely related to the pathogenesis of CHD, A allelic gene may be a susceptibility gene for CHD, and patients with abnormal HDC-C and carried A allelic gene had relatively higher incidence of CHD.

Dual Tumor Exosome Biomarker Co-recognitions Based Nanoliquid Biopsy for the Accurate Early Diagnosis of Pancreatic Cancer.

Pancreatic cancer, with extremely limited treatment options and poor prognosis, urgently needs a breakthrough in early diagnosis and monitoring. Tumor exosomes (T-Exos) detection is presently one of the most clinically significant liquid biopsy approaches for non-invasive pancreatic cancer early diagnosis, which, unfortunately, cannot be applied as a routine diagnostic tool until a number of obstacles, such as unsatisfactory specificity and sensitivity, as well as labor-intensive purification and analysis procedures by ultracentrifugation and enzyme-linked immunosorbent assay, are overcome. Here, we report a facile nanoliquid biopsy assay for the especially specific, ultrasensitive yet economical T-Exos detection by a dual specific biomarker antigen co-recognition and capturing strategy, which is enabled by grafting two corresponding capture antibodies on magnetic nanoparticles and gold nanoparticles, for the accurate detection of target tumor exosomes. This approach exhibits excellent specificity and ultrahigh sensitivity of detecting as low as 78 pg/mL pancreatic cancer exosome specific protein GPC1. Successful screening of 21 pancreatic cancer samples from 22 normal control cases with the enhanced specificity and sensitivity ensures the promising non-invasive monitoring and diagnosis for early stage pancreatic cancer.

Iron tolerant Bacillus badius mediated bimetallic magnetic iron oxide and gold nanoparticles as Doxorubicin carrier and for hyperthermia treatment

Among the different types of nanoparticles (NPs), iron oxide magnetic nanoparticles (IOMNPs) and bimetallic gold-magnetic iron oxide NPs (Au-IOMNPs) are gaining impetus for biomedical applications. Due to their unique properties such as super-paramagnetic behaviour, biocompatibility, and ease of surface modification, IOMNPs become suitable for drug delivery and hyperthermia applications. In this study, iron tolerant bacterium Bacillus badius was used in the optimized biogenic synthesis of gold NPs (AuNPs), IOMNPs, and bimetallic Au-IOMNPs and functionalized with doxorubicin (Dox). When analyzed by MTT assay, Dox functionalized Au-IOMNPs showed cytotoxicity against MCF7 cells line with an IC50 value of 147 μg/mL. Noteworthy, IOMNPs were found suitable for hyperthermia treatment as the temperature rise was up to 48 °C under an applied current of 400 Oe. Thus, this study demonstrated the application of Bacillus badius mediated IOMNPs and Au-IOMNPs for Dox delivery and hyperthermia treatment.

Monte Carlo simulation of physical dose enhancement in core-shell magnetic gold nanoparticles with TOPAS.

The application of metal nanoparticles (MNPs) as sensitization materials is a common strategy that is used to study dose enhancement in radiotherapy. Recent in vitro tests have revealed that magnetic gold nanoparticles (NPs) can be used in cancer therapy under a magnetic field to enhance the synergistic efficiency in radiotherapy and photothermal therapy. However, magnetic gold NPs have rarely been studied as sensitization materials. In this study, we obtained further results of the sensitization properties of the magnetic gold NPs (Fe3O4@AuNPs) with or without magnetic field using the TOPAS-nBio Monte Carlo (MC) toolkit. We analyzed the properties of Fe3O4@AuNP in a single NP model and in a cell model under monoenergetic photons and brachytherapy, and we investigated whether the magnetic field contributes to the physical sensitization process. Our results revealed that the dose enhancement factor (DEF) of Fe3O4@AuNPs was lower than that of gold nanoparticles (AuNPs) in a single NP and in a cell irradiated by monoenergetic photons. But it’s worth mentioning that under a magnetic field, the DEF of targeted Fe3O4@AuNPs in a cell model with a clinical brachytherapy source was 22.17% (cytoplasm) and 6.89% (nucleus) higher than those of AuNPs (50 mg/mL). The Fe3O4@AuNPs were proved as an effective sensitization materials when combined with the magnetic field in MC simulation for the first time, which contributes to the research on in vitro tests on radiosensitization as well as clinical research in future.

Super-assembly of integrated gold magnetic assay with loop-mediated isothermal amplification for point-of-care testing.

With the increasing global threat of various diseases and infections, it is essential to develop a fast, low-cost, and easy-to-use point-of-care testing (POCT) system for inspections at all levels of medical institutions and self-examination at home. In this work, gold magnetic nanoparticles (GMNPs) are used as the key material, and a rapid visual detection method is designed through integrating loop-mediated isothermal amplification (LAMP) and lateral flow assay (LFA) biosensor for detecting a variety of analytes which includes whole blood, buccal swabs, and DNA. It is worth to note that the proposed method does not need DNA extraction. Furthermore, uracil DNA glycosylase (UDG) is employed to eliminate carrier contamination for preventing false positive results. The whole detection process can be finished within 25 min. The accuracy of detection is measured by assessing the polymorphisms of the methylenetetrahydrofolate reductase (MTHFR) C677T. The detection limit of the newly developed extraction-free detection system for MTHFR C677T is 0.16 ng/μL. A preliminary clinical study of the proposed method is carried out by analyzing 600 clinical samples (including 200 whole blood samples, 100 buccal swabs, and 300 genomic DNA samples). The results indicate that the proposed method is 100% consistent with the sequencing results which provides a new choice for POCT and shows a broad application prospect in all levels of medical clinics and at home.Electronic Supplementary MaterialSupplementary material (details for MTHFR C677T primer sequences, the cell count results of samples at different dilution ratios, genotyping results and frequency samples, a Hardy—Weinberg equilibrium test, the sensitivity of the system, detection results of multiple samples, and optimization of the system) is available in the online version of this article at 10.1007/s12274-022-4692-9.

Recent Advances of Magnetic Gold Hybrids and Nanocomposites, and Their Potential Biological Applications

Magnetic gold nanoparticles (mGNP) have become a great interest of research for nanomaterial scientists because of their significant magnetic and plasmonic properties applicable in biomedical applications. Various synthetic approaches and surface modification techniques have been used for mGNP including the most common being the coprecipitation, thermal decomposition, and microemulsion methods in addition to the Brust Schiffrin technique, which involves the reduction of metal precursors in a two-phase system (water and toluene) in the presence of alkanethiol. The hybrid magnetic–plasmonic nanoparticles based on iron core and gold shell are being considered as potential theranostic agents. In this critical review, in addition to future works, we have summarized recent developments for synthesis and surface modification of mGNP with their applications in modern biomedical science such as drug and gene delivery, bioimaging, biosensing, and neuro-regeneration, neuro-degenerative and arthritic disorders. This review includes techniques and biological applications of mGNP majorly based on research from the previous six years.

Internet of things-based design of maternal and infant monitoring system and adoption of gold nanoparticles bacterial DNA detection technology in probiotic treatment of pregnancy reaction

it aimed to establish a maternal and child monitoring system based on medical Internet of Things (IoT) technology and explore the application of gold magnetic nanoparticles (Au-MNPs) in bacterial detection. The effect of active Bifidobacterium tablet (Siliankang) on intestinal flora of pregnant women and reaction to early pregnancy was analyzed. A real-time fetal heart rate monitoring method was established based on median filtering algorithm, and a maternal and infant monitoring system was established by organically combining portable monitoring equipment and hospital monitoring center through the IoT. Fe3O4 nanoparticles and Au-NPs were prepared by co-precipitation method and Turkevitch-Frens method. Fe3O4-Au-SiO2 NPs was obtained by polymerizing Au-NPs into Fe3O4 nanoparticles and coating the surface with SiO2. The characterization of NPs and its bacterial adsorption efficiency were analyzed, and a capture sensor for the detection of bacterial Deoxyribonucleic acid (DNA) was prepared. A total of 120 patients with pregnancy reaction were selected as the research object, and were divided into the placebo group and the experimental group (compound probiotics supplement group) according to different treatment methods, with 60 patients in each group. The bacterial DNA detection sensor was used to detect the difference of bacterial flora in feces of patients in different groups. The results showed that the particle size of Fe3O4-Au-SiO2 NPs was 15–47 nm, and the adsorption efficiency of Fe3O4-Au-SiO2 NPs to S. aureus, S. epidermidi, E. coli, and P. aeruginosa was higher than 80%. The Fe3O4-Au-SiO2 NPs of the prepared bacterial DNA detection sensor could be hybridized with the target bacterial DNA sequence. the intestinal enterobacteria, enterococci, and Bacteroides of patients in test group were remarkably reduced in contrast to control group, while the Bifidobacterium, Lactobacillus, and Fusobacterium flora were greatly increased (P < 0.05). the number of NVP patients in the control group and test group was 19 case (31.7%) and 5 case (8.3%). The probability of early pregnancy reaction was notably reduced (P < 0.05). It showed that the maternal and infant monitoring system based on Internet of things technology had potential application value for maternal and infant health. Tetralogy of viable Bifidobacterium tablets (Siliankang) can reduce the pathogenic bacteria in the intestines of pregnant women, and then reduced the incidence of early pregnancy reactions.

A Novel Fluorescence Aptasensor Based on Magnetic Beads/Gold Nanoparticles/DNA-Stabilized Silver Nanoclusters for Detection of Salmonella Typhimurium.

Salmonella Typhimurium (S. Typhimurium) is a globally distributed foodborne pathogen, which can lead to outbreaks of foodborne infectious diseases. It is essential to guarantee food safety by timely and correct detection of S. Typhimurium. In this investigation, an original fluorescence aptasensor was constructed to detect S. Typhimurium rapidly and sensitively. Through the coupling of magnetic beads, aptamer, and gold nanoparticles (AuNPs), a fluorescence quenching system with a “sandwich structure” was established. The aptamer acted as a link, and its specific binding to S. Typhimurium could release AuNPs from the system. Meanwhile, fluorescent DNA-stabilized silver nanoclusters (DNA-AgNCs) were synthesized. The fluorescence intensity changes caused by the fluorescence resonance energy transfer between DNA-AgNCs and AuNPs were utilized to detect S. Typhimurium. The purposed aptasensor exhibited high selectivity and sensitivity with a linear response to S. Typhimurium, ranging from 3.7 × 102 to 3.7 × 105 cfu/mL. The limit of detection (LOD) was estimated to be 98 cfu/mL within 2 h 10 min. In addition, this method showed excellent application for detection of S. Typhimurium in artificially contaminated milk, with LOD reaching 3.4 × 102 cfu/mL. Therefore, the developed fluorescence aptasensor has great potential to identify S. Typhimurium in foodstuffs.

Hybrid nanoparticles consisting of magnetic iron oxide and gold nanoparticles modified with Arabic gum

Hybrid nanoparticles consisting of magnetic iron oxide and gold nanoparticles modified with Arabic gum

Recent Progress of Magnetically Actuated DNA Micro/Nanorobots.

In the past few decades, the field of DNA origami-based micro/nanotechnology has developed dramatically and spawned attention increasingly, as its high integrality, rigid structure, and excellent resistance ability to enzyme digestion. Many two-dimensional and three-dimensional DNA nanostructures coordinated with optical, chemical, or magnetic triggers have been designed and assembled, extensively used as versatile templates for molecular robots, nanosensors, and intracellular drug delivery. The magnetic field has been widely regarded as an ideal driving and operating system for micro/nanomaterials, as it does not require high-intensity lasers like light control, nor does it need to change the chemical composition similar to chemical activation. Herein, we review the recent achievements in the induction and actuation of DNA origami-based nanodevices that respond to magnetic fields. These magnetic actuation-based DNA nanodevices were regularly combined with magnetic beads or gold nanoparticles and applied to generate single-stranded scaffolds, assemble various DNA nanostructures, and purify specific DNA nanostructures. Moreover, they also produced artificial magnetism or moved regularly driven by external magnetic fields to explain deeper scientific issues.