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Listeria monocytogenes (L. monocytogenes) is a zoonosis pathogen that can cause listeriosis with a high morbidity and mortality. Accordingly, a strategy with high sensitivity and exploitability for detecting L. monocytogenes must be developed. Herein, we introduced a double mediation system based on polyethylene glycol (PEG) and bovine serum albumin (BSA) to prepare teicoplanin (Teic)-functionalized magnetic beads (MBs). This system was then combined with monoclonal antibody-modified quantum dot microspheres (QBs), to develop a rapid and sensitive strategy for detecting L. monocytogenes. Teic, as an antibiotic, mainly bind to Gram-positive bacteria via forming the five-point hydrogen bond between the heptapeptide on its main chain and the terminal D-alanyl-D-alanine (D-Ala-D-Ala) on the cell wall of Gram-positive bacteria. In addition, the antibody guaranteed the specificity for L. monocytogenes detection. The capture efficiency (CE) of MBs-PEG-BSA-Teic for L. monocytogenes at the concentrations ranging from 2.6 × 101 CFU/mL to 2.6 × 104 CFU/mL exceeded 92% in phosphate-buffered saline (PBS) and 89% in the spiked ground beef samples. The limit of detection of the strategy for L. monocytogenes was 2.6 × 101 CFU/mL in both PBS and spiked ground beef samples. Therefore, the proposed strategy is capable of detecting L. monocytogenes with a high specificity and an excellent sensitivity.

As a new type of liquid biopsy, circulating tumor cell (CTC) detection and analysis offers the possibility to monitor metastatic development, cancer recurrence, and therapeutic efficacy in real time. However, the inherent rarity and heterogeneity of CTCs pose great challenges for CTC detection and analysis. Effective CTC capture and detection are therefore of great importance in cancer diagnosis and prognosis. Since virtually all biological materials are diamagnetic or only weak magnetic, magnetic particle-based magnetic capture and isolation methods are promising as CTC catchers. In this review, we focus attention on the progress of technologies utilizing magnetic particles to assist CTCs capture. We summarized the influence of the physicochemical properties of magnetic particles on CTC enrichment, and some general strategies for enhancing CTC capture based on magnetic particles. In addition, we also reviewed some of the application progress of magnetic nanoparticles in CTC capture and analysis.

The effect of one of the most widely studied nanomaterials at present, TiO2 nanoparticles (NPs), on pregnancy-related diseases is not clear. In this study, the adverse effects of TiO2 NPs on mice with gestational diabetes mellitus (GDM) and their possible mechanism were investigated. GDM mice were orally administered 0, 10, 50 and 250 mg/kg TiO2 NPs for 14 days. GDM reduced the weight of pregnant mice, destroyed the placental structure and caused abnormal fetal development. After exposure to increasing doses of TiO2 NPs, blood glucose levels increased significantly and body weight further decreased in GDM mice. The accumulation of the Ti content was detected in the placenta and fetus, which may further damage the placental structure in GDM mice, thereby exacerbating abnormal fetal development. In addition, the MDA and SOD activities were obviously increased, and the expression of genes associated with endoplasmic reticulum stress (ERS) (PERK, eIF2α, AFT4, IRE1α, and XBP1s) and apoptosis (CHOP, JNK, Bax/Bcl-2, Caspase-12, Caspase-9, and Caspase-3) were also obviously increased in the placenta, which reflected the possible activation of apoptosis. It could be speculated that the reproductive toxicity of TiO2 NPs in GDM mice triggered oxidative stress that subsequently activated ERS pathways to induce cell apoptosis.

In this work, we study the band structures and intrinsic anomalous Hall conductivity (AHC) of the ferromagnetic multiorbital tight-binding (TB) model derived from the transition metal compound Sr$_2$RuO$_4$ under periodic driving of monochromatic polarized light. Within the framework of the Floquet theory, we adopt the continued fraction technique to attain the effective Hamiltonian valid in the weak-driving and low-frequency regimes, and the related Green's functions which are further employed for the transport calculations based on the Kubo formalism. The high-frequency circularly and linearly polarized (LP) light has limited impacts on the band structures, while the low-frequency light with the photon energy smaller than the bandwidth of the system opens up bandgaps at the edges of the Floquet-Brillouin zone (FBZ) since the transitions between Floquet sidebands become significant. For intrinsic AHC, the left-handed circularly polarized (LCP) light plays a distinct role on AHC compared to the right-handed circularly polarized (RCP) light. Furthermore, it reveals that the roles of LCP and RCP light can be interchanged by altering the incident plane of light. Finally, the intrinsic AHC with the interplay between the short-range disorder and circularly polarized light is also investigated.

Due to the massive use of antibiotics, clinical highly pathogenic bacteria methicillin-resistant Staphylococcus aureus (MRSA) have emerged. Given its non-uniform drug resistance, it brings numerous difficulties for clinical diagnostic tests. This study aimed to establish a fast and accurate method to detect MRSA in hospital samples. In order to shorten the detection time and eliminate the influence of matrix on the detection results, so as to improve the detection sensitivity. In this study, magnetic separation (MS) technology was used for pre-treatment of samples, and triplex PCR was established using mecA, nuc and flic genes to realize the detection of MRSA. The results showed that the lowest detection limit of MRSA in blood samples and cerebrospinal fluid could reach 102 CFU/mL and 103 CFU/mL. Therefore, the MS technology combined with triplex PCR assay established in this study is expected to provide a strong basis for the detection of MRSA in hospital samples.

Cronobacter sakazakii, Bacillus cereus, and Salmonella spp. are common food-borne pathogens. The aim of this study was to develop a sensitive, specific, and rapid method for the simultaneous detection of these 3 pathogens in milk and milk products. Three specific primers were designed based on ompA, invA, and cesB of C. sakazakii, Salmonella spp. and B. cereus, respectively, for use in a multiplex PCR (mPCR). To eliminate false-positive results, cells were pretreated with propidium monoazide (PMA) for the selective elimination of the genomic DNA of dead cells. An internal amplification control was applied as an indicator of false-negative results from the interference of inhibitors in the food matrix. Results showed that, in pure culture, the limits of detection of the assay for C. sakazakii, Salmonella Enteritidis, and B. cereus were 9.5 × 104, 7.4 × 102, and 7.5 × 102 cfu/mL, respectively. Moreover, 8 cfu/mL of viable B. cereus cells were detected after 5 h of enrichment, and 9 cfu/mL of viable C. sakazakii and 7 cfu/mL of Salmonella Enteritidis were detected after 7 h of enrichment in spiked pure milk, walnut peanut milk, and whole-wheat milk. To validate the PMA-mPCR assay, the PMA-mPCR assay and the traditional culture method were performed to detect the 3 bacterial strains in 1,165 milk product samples. The PMA-mPCR assay obtained the same results as the culture-based method. Results demonstrated that the PMA-mPCR assay has excellent sensitivity and specificity for the simultaneous detection of viable C. sakazakii, Salmonella Enteritidis, and B. cereus in milk and milk products.

We report in this study a method of synthesizing silver nanoparticles (AgNPs) by using the leaf extract of Cinnamomum camphora and evaluate their antimicrobial proficiency. The analysis from transmission electron microscopy indicates that the shapes of the biosynthetic AgNPs were uniformly dispersed spherical or ellipsoidal, and the average particle size was 19.57 nm. According to the results of dynamic light scattering, the zeta potential was −29.0 mV with good stability. Then, as detected by X-ray diffraction and selected electron diffraction, the AgNPs were a face-centered cubic lattice. The Fourier transform infrared spectroscopy also showed that the extract contained large amounts of reducing and stable components. The biosynthetic AgNPs achieved good antimicrobial activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans. The minimum inhibitory concentration of the gram (–) bacteria was 3 μg/mL. Then, the changes in the S. aureus and E. coli were further observed by scanning electron microscopy and other means, in which the AgNP treatment was prepared with slightly lower concentration than the minimum inhibitory concentration. The low-dose AgNPs could cause damage to S. aureus and E. coli. This green synthesis method for the AgNPs, with its merit of being able to reduce pollution, may serve as a good substitute to the traditional methods.

Cronobacter spp. are important opportunistic foodborne pathogens in powdered infant formula (PIF). In this study, a sensitive and specific assay was developed for fluorescent and colorimetric detection of Cronobacter spp. in PIF samples by using ligase chain reaction and rolling circle amplification (LCR-RCA) dual-amplification strategy. A pair of gap-padlock probes was designed to induce specific genomic DNA recognition and initiate the LCR. Hyperbranched rolling circle amplification (HRCA) combined with fluorescent dye and linear rolling circle amplification (LRCA) with AuNP probes were performed to achieve fluorescent or colorimetric detection of Cronobacter spp. The limits of detection (LODs) of the proposed assays were 8.6 × 101 CFU/mL (fluorescence) and 7.5 × 102 CFU/mL (colorimetric) in pure culture and 9.2 × 102 CFU/mL (fluorescence) and 8.4 × 103 CFU/mL (colorimetric) in spiked PIF samples, respectively. After 5–7 h enrichment, the proposed methods could detect as low as 100 CFU/mL bacteria in pure culture and PIF sample. The recovery of both methods was in the range of 89.4%–103.8% in pure culture or spiked PIF samples. The proposed assay has the potential to be a rapid and efficient method for detection of Cronobacter spp. in PIF.

Pseudomonas aeruginosa is one of the most commonly isolated nosocomial pathogens and is responsible for approximately 10 % of all hospital-acquired infections. P. aeruginosa is difficult to treat with known antibiotics due to its increasing antibiotic resistance. In our study, Ag NPs coated with e-polylysine (e-PL) and polyethyleneimine (PEI) were synthesized. These materials showed strong anti-P. aeruginosa capacity at an low concentration (IC50: 7.284 μg/mL). In addition, three drug-resistant clinical strains and biofilm formation were inhibited by e-PL/PEI-coated Ag NPs (MBIC: 15.63 μg/mL). We further studied the antibacterial mechanism of Ag NPs on different levels and found that a) the amount of reactive oxygen species (ROS) increased, b) the expression of oxidative stress-related genes were up-regulated, c) the activity of total superoxide dismutase decreased, and d) the inhibitory rate is increased on P. aeruginosa cells. These antibacterial effects were dependent on an increasing concentration of Ag NPs but were neutralized by the ROS scavenger N-acetyl-L-cysteine. Therefore, we suggested that oxidative stress induced by ROS is the primary antibacterial mechanism of synthesized Ag NPs.

In this study, vancomycin (Van) functionalized PEGylated-magnetic nanoparticles (Van-PMs) combined with polymerase chain reaction (PCR) showed great potential for highly efficient detection of L. monocytogenes at low infectious dose. Herein, Van-PMs played as universal molecular probes for targeting bacterial cells, while PEG was used to help Van close to D-alanyl- d -alanine (D-Ala- d -Ala) moieties on surface of L. monocytogenes. Under optimum conditions, the developed Van-PMs complexes exhibited extremely high capture efficiency (CE) in a 10 mL bacterium suspension with the value was higher than 90% and 83% in the phosphate-buffered saline (PBS) solution and lettuce samples, respectively. Meanwhile, Gram-negative bacteria slightly influenced CE even under concentrations as high as 106 CFU/mL. The assay of Van-PMs-PCR was applied to detect L. monocytogenes with detection limits of 30 CFU/mL and 30 CFU/g in PBS solution and lettuce samples, respectively. The whole experiment was completed within 4 h. This assay demonstrated the potential of this modified method in practical application involving the detection of L. monocytogenes or other Gram-positive pathogenic bacteria.

Salmonella Enteritidis, Eschericha coli O157:H7 and Listeria monocytogenes are important pathogens contaminating fresh vegetables. The aim of this study was to develop a rapid and accurate approach for simultaneous detection of viable S. Enteritidis, E. coli O157:H7 and L. monocytogenes in fresh vegetables. To detect viable cells, propidium monoazide (PMA) was applied to eliminate the false-positive results. In addition, an internal amplification control (IAC) was added to the quadruplex PCR as indicator of false negative results that are mainly caused by the PCR inhibitors. The limit of detection (LOD) for the viable cells with or without PMA treatment was 102 CFU/mL for S. Enteritidis, 103 CFU/mL for E. coli O157:H7 and 104 CFU/mL for L. monocytogenes, showing that the PMA treatment did not influence the sensitivity. After 12 h enrichment, the PMA-mPCR-IAC combination assay could detect as low as 101 CFU/g for viable S. Enteritidis, E. coli O157:H7 and L. monocytogenes in spiked vegetables. The PMA-mPCR-IAC combination assay holds promise for the simultaneous detection of viable S. Enteritidis, E. coli O157:H7 and L. monocytogenes in fresh vegetables.

A novel sandwich strategy was designed to detect Staphylococcus aureus. The strategy is based on an antibacterial agent that captures bacterial cells and a fluorescein-labeled antibody that acts as the signal-output probe. Vancomycin (Van), which exerts a strong antibacterial effect on Gram-positive bacteria, was utilized as a molecular recognition agent to detect pathogenic bacteria. To effectively concentrate S. aureus, we used bovine serum albumin (BSA) as the amplification carrier to modify magnetic beads (MBs), which were then functionalized with Van. To improve the specificity of the method for S. aureus detection, we adopted fluorescein isothiocyanate (FITC)-tagged pig immunoglobulin G (FITC-pig IgG) as the signal probe and the second recognition agent that bound between the Fc fragment of pig IgG and protein A in the surface of S. aureus. To quantify S. aureus, we measured the fluorescence signal by flow cytometry (FCM). The use of multivalent magnetic nanoprobes (Van-BSA-MBs) showed a high concentration efficiency (98%) at bacterial concentrations of only 33 colony-forming units (CFU)/mL. Furthermore, the sandwich mode (FITC-pig IgG/SA/Van-BSA-MBs) also showed ideal specificity because Van and IgG bound with S. aureus at two distinct sites. The detection limit for S. aureus was 3.3 × 10

Salmonella is one of the most common pathogens that cause foodborne diseases in humans, resulting in high medical and economical costs worldwide. The aim of this study was to develop a rapid and accurate approach for simultaneous detection of viable Salmonella spp. in raw meat, including Salmonella enterica serovars Paratyphi B, S. Typhimurium, and S. Enteritidis. To reduce detection time and improve sensitivity, immunomagnetic separation (IMS) was used as a pre-concentration and separation method. In addition, false positive and false negative results were removed by combining propidium monoazide (PMA) treatment with internal amplification control. Results showed that the detection limit of IMS-PMA combined with sextuplex polymerase chain reaction (PCR) assay reached as low as 101 CFU/mL in pure culture and 102 CFU/g in spiked raw meat (ground pork and ground beef), and the total assay time took less than 6 h. Thus, the novel IMS-PMA-mPCR assay developed in this study holds promise for routine screening of viable Salmonella serovars in meat and other samples.

Cronobacter sakazakii , Staphylococcus aureus , and Bacillus cereus are important pathogens contaminating infant food products. In this study, we developed a specific, sensitive, and accurate technique for the simultaneous detection of viable C. sakazakii , S. aureus , and B. cereus in infant food products. An internal amplification control (IAC) was added to the multiplex PCR (mPCR) as indicator of false negative results that are mainly caused by the PCR inhibitors in food products. In addition, to detect only the viable bacteria, propidium monoazide (PMA) was applied to selectively suppress the PCR signal from dead cells. The limit of detection (LOD) for the viable cells with or without PMA treatment was 10 4 CFU/mL for C. sakazakii and B. cereus , and 10 2 CFU/mL for S. aureus in pure culture, showing that the PMA treatment did not influence the sensitivity. After 12 h enrichment, the PMA-mPCR-IAC assay could detect as low as 10 1 CFU/g for C. sakazakii and S. aureus , and 10 0 CFU/g for B. cereus in spiked infant food products (infant formula, noodles, milk and rice noodles). This PMA-mPCR-IAC assay we developed hold promise for the simultaneous detection of C. sakazakii , S. aureus , and B. cereus in infant food products.

A rapid, reliable, and sensitive method for the detection of Cronobacter sakazakii, a common foodborne pathogen that may cause serious neonatal disease, has been developed. In this study, a rapid real-time quantitative PCR (qPCR) assay combined with sodium deoxycholate (SD) and propidium monoazide (PMA) was developed to detect C. sakazakii contamination in powdered infant formula (PIF). This method could eliminate the interference from dead or injured bacteria. Optimization studies indicated that SD and PMA at 0.08% (wt/vol) and 5µg/mL, respectively, were the most appropriate. In addition, qPCR, PMA-qPCR, SD-PMA-qPCR, and plate count assays were used to account for the number of viable bacteria in cell suspensions that were exposed to a 55°C water bath at different length of time. As a result, the viable number by PMA-qPCR showed significantly higher than of the number from SD-PMA-qPCR or plate counts. The number of viable bacteria was consistent between SD-PMA-qPCR and traditional plate counts, which indicated that SD treatment could eliminate the interference from dead or injured cells. Using the optimized parameters, the limit of detection with the SD-PMA-qPCR assay was 3.3×102 cfu/mL and 4.4×102 cfu/g in pure culture and in spiked PIF, respectively. A similar detection limit of 5.6×102 cfu/g was obtained in the presence of the Staphylococcus aureus (107 cfu/mL). The combined SD-PMA-qPCR assay holds promise for the rapid detection of viable C. sakazakii in PIF.

ZnO nanoparticles (NPs) have been assessed to show adverse effects on the liver, but the molecular mechanisms and the role of nanoparticle properties in these adverse reactions have not been sufficiently studied. In this study, the toxicity of various sizes of ZnO particles (bulk, 90nm, and 30nm) that were ingested orally over a period of 3days were evaluated in mice. The blood biochemistry, hematological analyses, and histopathological evaluation showed that there was apparent toxicity caused by smaller ZnO NPs (30nm) in liver. The smallest ZnO NPs showed highest accumulation in the mice liver. The RT-qPCR data indicated that 30nm ZnO NPs can induce significant endoplasmic reticulum (ER) stress responses. The ER stress marker of PERK, eIF2α, ATF4, Chop, JNK, caspase-12, caspase-9, GRP94, and Bax at the mRNA levels were higher expression in 30nm ZnO NP than that in bulk or 90nm ZnO. These findings implied that the smaller ZnO NPs (30nm) activated ER stress responses that signified severe apoptosis in murine liver.

In this study, the effects of cadmium containing QDs (such as CdSe/ZnS and CdSe QDs) and bulk CdCl2 in pregnant mice, their fetuses, and the pregnancy outcomes were investigated. It was shown that although the QDs and bulk CdCl2 were effectively blocked by the placental barrier, the damage on the placenta caused by CdSe QDs still led to fetus malformation, while the mice in CdSe/ZnS QDs treatment group exhibited slightly hampered growth but showed no significant abnormalities. Moreover, the Cd contents in the placenta and the uterus of CdSe QDs and CdSe/ZnS QDs treatment groups showed significantly higher than the CdCl2 treated group which indicated that the nanoscale size of the QDs allowed relative ease of entry into the gestation tissues. In addition, the CdSe QDs more effectively altered the expression levels of susceptive genes related to cell apoptosis, dysplasia, metal transport, cryptorrhea, and oxidative stress, etc. These findings suggested that the nanoscale size of the QDs were probably more important than the free Cd in inducing toxicity. Furthermore, the results indicated that the outer surface shell coating played a protective role in the adverse effects of QDs on late pregnancy mice.

Ultra-fine-ZnO showed low toxicity in complex water matrix containing multiple components such as PBS buffer and the toxic mechanism of ultra-fine-ZnO has not been clearly elucidated. In present study, enhanced antibacterial activity of 200 nm diameter ultra-fine-ZnO in PBS buffer against Bacillus cereus and Escherichia coli were observed in the presence of several organic acids in comparison with ultra-fine-ZnO in PBS buffer alone. These findings indicated that the toxic effects of the ultra-fine-ZnO was dependent on the concentration of released Zn2+ which was affected by organic acids. The production of reactive oxygen species (ROS) did not responsible to the toxic mechanism of ultra-fine-ZnO which was tested using the antioxidant N-Acetylcysteine (NAC). Indeed, ultra-fine-ZnO induced bacteria cell membrane leakages and cell morphology damages that eventually led to cell death, which were confirmed using propidium monoazide (PMA) in combination with PCR and scanning electron microscopy (SEM). All data gathered herein suggested that released Zn2+ played a major role in the microbial toxicity of ultra-fine-ZnO.

We study theoretically the effects of long-range and on-site Coulomb interactions on the topological phases and transport properties of spin–orbit-coupled quasi-one-dimensional quantum wires imposed on a s-wave superconductor. The distributions of the electrostatic potential and charge density are calculated self-consistently within the Hartree approximation. Due to the finite width of the wires and charge repulsion, the potential and density distribute inhomogeneously in the transverse direction and tend to accumulate along the lateral edges where the hard-wall confinement is assumed. This result has profound effects on the topological phases and the differential conductance of the interacting quantum wires and their hybrid junctions with superconductors. Coulomb interactions renormalize the gate voltage and alter the topological phases strongly by enhancing the topological regimes and producing jagged boundaries. Moreover, the multicritical points connecting different topological phases are modified remarkably in striking contrast to the predictions of the two-band model. We further suggest the possible non-magnetic topological phase transitions manipulated externally with the aid of long-range interactions. Finally, the transport properties of normal–superconductor junctions are further examined, in particular, the impacts of Coulomb interactions on the zero-bias peaks related to the Majorana fermions and near zero-energy peaks.

As the main factor leading to foodborne illnesses, foodborne pathogens have been attached great importance by people. The development of simple, rapid, high-sensitivity and low-cost food-borne pathogen detection methods is of great significance in reducing the incidence of foodborne diseases. Biosensor technology is a new micro-analysis technology developed by multi-disciplinary cross-infiltration. It has the characteristics of high sensitivity and fast analysis speed, and is widely used in the detection of food-borne pathogens. This paper introduces the basic principles of biosensors, summarizes the application of common biosensors in the detection of foodborne pathogens, and prospects for future development.食源性致病菌作为引起食源性疾病的主要因素，受到人们的高度重视，发展简便、快速、高灵敏度和低成本的食源性致病菌检测方法对降低食源性疾病发病率具有重要意义。生物传感器技术是一种由多学科交叉渗透发展形成的全新微量分析技术，具有灵敏度高、分析速度快等特点，被广泛应用于食源性致病菌的检测。文中介绍了生物传感器的基本原理，综述了常见的生物传感器在食源性致病菌检测中的应用，并对其发展趋势进行了展望。.

Cronobacter spp. are important opportunistic foodborne pathogens in powdered infant formula that cause many serious diseases in neonates and infants. In this study, a novel assay based on dual signal amplification strategy was developed by coupling asymmetric tailing PCR (AT-PCR) with rolling circle amplification (RCA) for the detection of Cronobacter spp. in milk. The tailing single-stranded DNA was generated through AT-PCR and used to initiate RCA, generating tandem repetitive G-quadruplex sequences. In the presence of the fluorescence dye thioflavin T that could intercalate into the G-quadruplex structures, the fluorescence signal was detected with a microplate reader. The AT-PCR coupled with RCA assay was specific for Cronobacter spp. detection because of the highly specific primers chosen for the AT-PCR. The limits of detection were 4.3 × 101 cfu/mL in pure culture and 4.5 × 102 cfu/mL in spiked milk, respectively. The fixed sequences designed in the hairpin DNA allowed this AT-PCR coupled with RCA assay to serve as a universal platform for the detection of other pathogens by modifying the specificity of the PCR primers.

Rolling circle amplification is a rapid, sensitive and isothermal single-stranded DNA amplification technique that can be used with staining or probes to amplify the detection signal. This technology has been widely used in biological detection and other aspects. The present paper introduces how to design rolling circle amplification, summarize its application in the detection of pathogens, nucleic acid tumor markers, proteins, biological small biomolecules, and viruses in recent years and prospects for future development.滚环扩增 (Rolling circle amplification ， RCA) 是一种快速、灵敏且恒温的单链DNA(Single-stranded DNA，ssDNA) 扩增技术，与染色或探针联用可实现检测信号的放大，在生物检测等方面得到广泛的应用。文中对RCA 的构建方法进行了简介，综述了近几年其在致病菌、核酸肿瘤标记物、蛋白质、生物小分子和病毒等检测中的研究进展，并对其未来的发展趋势进行了展望。.

Emetic Bacillus cereus is one of the causative agents of foodborne diseases which can cause vomiting-type food poisoning after ingestion of contaminated food. To minimize B. cereus food poisoning, propidium monoazide (PMA) combined with quantitative polymerase chain reaction (qPCR) called PMA-qPCR was applied for detecting viable emetic B. cereus in milk. The cereulide synthetase gene of emetic B. cereus (cesB) was chosen for the primer, and PMA treatment was optimized at 3 μg/mL to inhibit the PCR amplification of DNA from dead cells. Under optimized assay parameters, the limit of detection (LOD) using this method were 102 CFU/mL in both pure culture and in spiked milk matrix. The cycle threshold (Ct) values obtained for this assay was not significantly affected by the presence of non-target bacteria such as E. coli O157:H7 which indicated the high selectivity of the assay for emetic B. cereus. The PMA-qPCR assay used in this study has the potential for sensitive detection of viable emetic B. cereus in milk.

We study the band structures and time-averaged transport properties of the Floquet systems irradiated by variously polarized monochromatic light theoretically based on the Floquet-Green's function method. It reveals that the circularly polarized light can generate the anisotropic chiral edge modes and the polarization of light further manipulates these modes by altering their spatial distributions and spin orientations. Benefitting from external electric and exchange fields, the valley polarizations and band gaps can be induced to implement a variety of exotic photo-dressed topological phases. Furthermore, the circularly polarized light modifies the spin-resolved dc conductance remarkably, giving rise to a highly spin-polarized transport in the bulk band-gap regime. The short-range disorder manifests itself by forming a conductance arc symmetrically with respect to zero energy as well as a half-integer quantized conductance plateau in the two-terminal Floquet devices. The transverse dc conductance in T-shape devices is sensitive to the polarization of light; namely, the left-circularly polarized light minimizes the transverse conductance while the right-handed one greatly enhances it by inverting the moving directions of the edge modes. The strong correlation between the spin and light polarizations offers us a feasible tool to either realize devices in spintronic or detect the polarization of monochromatic light by simple transport measurements.

A fluorescence assay combined with PCR, catalytic hairpin assembly (CHA), and graphene oxide (GO) was established to detect emetic Bacillus cereus in milk samples. The processes of the assay are not new, but components of the processes make the assay useful. Two partially complementary hairpin probes (H1 and FAM-H2) were designed according to the target single-strand DNA (ssDNA). The CHA reaction could be initiated only by the target ssDNA, which was generated by the denaturation of PCR amplicons. In the absence of the target ssDNA, CHA reaction could not be triggered, which caused the H1 and FAM-H2 adsorbing on the surface of GO and exhibiting a low fluorescence intensity. Addition of the target ssDNA resulted in opening of the hairpin H1 that subsequently hybridized with H2. Then, target ssDNA would be replaced from the H1 and recycled to promote another CHA reaction. Through the CHA reaction, multiple H1-H2 duplexes were generated that could not adsorb on the surface of GO. Thus, a strong fluorescence signal would be obtained. The assay showed a limit of detection for emetic B. cereus of 6.2 × 101 cfu/mL in pure culture and 5.9 × 102 cfu/mL in spiked milk without enrichment. By changing the PCR primer, the assay developed in this study had potential to detect other bacteria.

The potential toxicity of titanium dioxide nanoparticles (TiO2 NPs) to mammals has become a widespread concern. Young individuals exposed to TiO2 NPs have a higher risk than adults. In this study, the protective effects of Lactobacillus rhamnosus GG (LGG) on liver toxicity in young rats induced by TiO2 NPs were explored. Results show that the four-week-old rats that underwent LGG after the oral intake of TiO2 NPs could prevent weight loss, reduce hematological indicators (WBC and NEUT) and serum biochemical indicators (AST, ALT, AST/ALT, and ALP). Moreover, it alleviated the pathological damage of the liver (as indicated by the disordered hepatocytes, more eosinophilic, ballooning degeneration, and accompany with blood cells), but it did not reduce the Ti contents in the liver. In addition, RT-qPCR results indicated that LGG restored the expression of anti-oxidative stress-related genes, such as SOD1, SOD2, CAT, HO-1, GSH, GCLC, and GCLM in the liver. In summary, the hepatotoxicity of TiO2 NPs in young rats is closely related to oxidative stress, and the antioxidant effect of LGG might protect the harmful effects caused by TiO2 NPs.

Titanium dioxide nanoparticles (TiO2 NPs) are amongst the most frequently used nanomaterial in everyday consumer products, and their widespread applications have raised concerns of the consequent deleterious effects on human health, particularly to vulnerable populations, such as lactating females remains elusive. Therefore, this study was initiated to investigate the detrimental effects and toxic mechanisms induced by TiO2 NPs in maternal dams and offspring during the lactation period. Dams were randomly divided into three groups. The water (Control; Group I) and TiO2 NPs (100 mg/kg; Group II) were orally administered from postnatal day 1–20, respectively. The results indicated that TiO2 NPs could cause toxicity in the dams, such as pathological damages to mammary gland tissues. The excessive accumulation of TiO2 NPs could induce oxidative stress in the mammary gland, leading to the dysfunctional blood-milk barrier; besides, TiO2 NPs could also be transferred to offspring via breastfeeding, causing abnormal development of infant. We further accessed the possible underlying molecular mechanism; for this, we orally administered TiO2 NPs with vitamin E (100 mg/kg; Group III). The results revealed that toxicity induced by TiO2 NPs was rescued. Collectively, this study presented the deleterious pathological effects of oral exposure to TiO2 NPs in the mammary gland tissues and blood-milk barrier via the production of reactive oxygen species (ROS) in dams and developmental concerns in offspring. However, the administration of VE could mitigate the toxic effects induced by the TiO2 NPs.

Staphylococcus aureus is a common foodborne pathogenic microorganism. A modified propidium monoazide (PMAxx) dye combined with recombinase aided amplification (RAA) was proposed for the rapid and real-time detection of viable S. aureus. PMAxx, a kind of nucleic acid dye is used to distinguish viable bacteria from dead bacteria. Additionally, RAA technique has the advantage of a short detection time (20 min) and uniform temperature (39 °C), which is of great significance for the efficient detection of S. aureus. The S. aureus nuc gene was used as primer and probe in a microplate assay. The effect of PMAxx treatment exhibited permeation of the dead cell membranes that was observed under confocal laser scanning microscope (CLSM). After the enrichment of viable target bacteria ranging from 5.4 × 101 to 5.4 × 103 CFU/mL, the LOD for viable S. aureus was 102 CFU/mL under 3 h enrichment and 101 CFU/mL under 6 h enrichment in artificially contaminated milk, respectively. In the presence of nontarget bacteria at 106 CFU/mL, the system could detect 107 CFU/mL S. aureus in milk sample. The proposed PMAxx-RAA assay exhibited potential for the accurate and rapid viable S. aureus detection in milk.

Human were given a lot of opportunities to ingest TiO2 NPs in the environment. Children have low, sensitive intestinal tolerance, and they could be exposed to higher levels of TiO2 NPs than adults. Few studies have been conducted on the interaction between TiO2 NPs and juvenile intestine phase models. Thus, in this work, weaning rats were orally exposed to TiO2 NPs for 7 and 14 days. Results indicate that Ti accumulated in the intestine, liver, and feces. Inflammatory infiltration damage was observed in the colonic epithelial tissue, and gut microbiota fluctuated with a decreased abundance of Lactobacilli in feces. Oral supplementation with Lactobacillus rhamnosus GG (LGG) lessened TiO2 NPs-induced colonic inflammatory injury, which might due to downregulation of nuclear factor kappa-B (NF-κB). Meanwhile, LGG maintained normal intestinal microbiome homeostasis, thereby improving TiO2 NPs-induced colon injury in juvenile rats. Moreover, fecal microbiota transplant (FMT) experiment indicated possible TiO2 NPs-induced intestinal microbiota disorder led to colonic inflammation. Our works suggested the urgent need for additional studies on the risk safety assessment, mechanism, and prevention of juvenile health damage from exposure to TiO2 NPs.

Bacillus cereus is a major foodborne pathogen that can cause a type of diarrhea. Diarrheal syndrome results from the ingestion of food products contaminated with enterotoxin-producing B. cereus. This study investigated the presence of four enterotoxins genes in 130 B. cereus isolated from various food products from Jiangxi, China. The expression levels of the enterotoxin genes in three B. cereus strains of different origins were subsequently analyzed. All of the B. cereus strains harbor at least 1 enterotoxin gene, whereas 34 strains harbor 2 enterotoxin genes, 44 strains harbor 3 enterotoxin genes, and 47 strains carry all of the four enterotoxin genes. The detection rates of the cytK, hblD, nheA, and entFM enterotoxin genes in all B. cereus isolates were 71%, 43%, 92%, and 99%, respectively. Moreover, the food matrix significantly affected the expression of these enterotoxin genes. The majority of the enterotoxin genes were also downregulated in four food matrices, indicating that the relative expression of certain enterotoxin genes, especially the entFM gene, was lower in a real food matrix than in laboratory broths. Hence, these data revealed that B. cereus is a serious health hazard and that the food matrix may influence the virulence expression of B. cereus. Our results provide better insights into the physiology of the microorganism grown in food products.

The goal of this study was to evaluate the viability and gene expression relating to probiotic functionality of encapsulated Lactobacillus plantarum CCTCC M 2014170 during freeze-drying. Sodium alginate with or without inulin was applied as an inner layer and skim milk was used as an outer layer for coating sodium alginate particles. The results indicated that skim milk coated inulin-sodium alginate (ISA) encapsulation beads improved the survival of L. plantarum during exposure to adverse environment. The viability of L. plantarum from ISA encapsulation beads did not change after 2 h incubation in simulant gastric fluid (SGF). In 1% bile salt solution, the L. plantarum from ISA encapsulation beads only had 1.21 log CFU/mL reduction after 2 h treatment. After 7 weeks storage, the survival rate of L . plantarum was 20.89%, which showed reduction from 8.52 to 7.84 log CFU/mL. In addition, all genes relating to probiotic functionality of L. plantarum were similarly but not significantly up-regulated except the plnEF , which exhibited the highest up-regulation at more than 17-fold increase. This study indicated that encapsulation with alginate and skim milk in the presence of inulin before freeze-drying protected and improved the probiotic functionality of L. plantarum from the adverse freeze drying environment.

Plasmonic enzyme-linked immunosorbent assay (pELISA) based on catalase (CAT)-mediated gold nanoparticle growth shows great potential for the determination of disease-related biomarkers at ultralow concentrations by using sandwich formats. However, the relatively low sensitivity of this strategy using competitive formats limits its adoption for hapten detection. Herein, we present an improved competitive pELISA for ultrasensitive detection of ochratoxin A (OTA), where silica nanoparticles carrying poly(acrylic acid) brushes (SiO2@PAA) were used to decrease the affinity of competing antigens to anti-OTA monoclonal antibodies and amplify the signal as a "CAT container" (SiO2@PAA@CAT). The developed competitive pELISA exhibits extremely high sensitivity for OTA with detection limits of 10(-18) and 5 × 10(-20) g/mL by the naked eye and microplate reader, respectively. These values are at least 7 orders of magnitude lower than that of competitive CAT-based pELISA (10(-11) g/mL by the naked eye) and 8 orders of magnitude lower than that of horseradish peroxidase-based conventional ELISA (10(-11) g/mL by the microplate reader), respectively. Reliability and robustness of the proposed method were evaluated using actual agricultural products and human serum samples. This study demonstrated the potential of this modified method in practical applications involving the ultrasensitive detection of mycotoxins or other haptens.

Multiplex polymerase chain reaction (mPCR) has been widely used for the simultaneous detection of various target bacteria in vegetables. However, an enrichment period is necessary to improve the sensitivity of the mPCR method. In this paper, large-volume (10 mL) immunomagnetic separation (IMS) combined with mPCR for the rapid detection of Listeria monocytogenes and Listeria ivanovii in lettuce without further enrichment process is reported for the first time. Various parameters that affected the capture efficiency (CE) of IMS, including the amounts of streptavidin and biotinylated anti- Listeria monoclonal antibodies on the surface of magnetic nanobeads, the amount of immunomagnetic beads, immunoreaction time, and magnetic separation time, were systematically investigated. Moreover, the concentrations of primers, PCR conditions, and genomic DNA isolation for mPCR assay were optimized. Under optimum conditions, the CE of large-volume IMS for L . monocytogenes and L . ivanovii was greater than 90% when the concentration of target bacteria was less than 10 6 CFU/mL in pure culture, and was more than 80% when the concentration was below 10 5 CFU/mL in lettuce samples. The limit of detection of IMS combined with mPCR assay reached as low as 1.0 CFU/mL in pure culture and 10 CFU/g in lettuce. The overall assay time, including sample preparation, large-volume IMS, and mPCR assay, took less than 7 h. In summary, the developed large-volume IMS-based mPCR system exhibits great potential for routine screening detection of foodborne pathogenic bacteria for safety monitoring.

Herein, for the first time we report an improved competitive fluorescent enzyme linked immunosorbent assay (ELISA) for the ultrasensitive detection of ochratoxin A (OTA) by using hydrogen peroxide (H2O2)-induced fluorescence quenching of mercaptopropionic acid-modified CdTe quantum dots (QDs). In this immunoassay, catalase (CAT) was labeled with OTA as a competitive antigen to connect the fluorescence signals of the QDs with the concentration of the target. Through the combinatorial use of H2O2-induced fluorescence quenching of CdTe QDs as a fluorescence signal output and the ultrahigh catalytic activity of CAT to H2O2, our proposed method could be used to perform a dynamic linear detection of OTA ranging from 0.05 pg mL(-1) to 10 pg mL(-1). The half maximal inhibitory concentration was 0.53 pg mL(-1) and the limit of detection was 0.05 pg mL(-1). These values were approximately 283- and 300-folds lower than those of horseradish peroxidase (HRP)-based conventional ELISA, respectively. The reported method is accurate, highly reproducible, and specific against other mycotoxins in agricultural products as well. In summary, the developed fluorescence immunoassay based on H2O2-induced fluorescence quenching of CdTe QDs can be used for the rapid and highly sensitive detection of mycotoxins or haptens in food safety monitoring.

Plasmonic enzyme-linked immunosorbent assay (pELISA) based on catalase (CAT)-mediated gold nanoparticle growth exhibits ultrahigh sensitivity for detecting disease-related biomarkers using sandwich formats. However, the limit of detection (LOD) of this strategy for Listeria monocytogenes is only around 10(3) CFU/mL, which considerably exceeds the amount of L. monocytogenes commonly present in food products (100 CFU/g). Herein, we report an improved pELISA method for detection of L. monocytogenes at ultralow concentrations with the sandwich formats using silica nanoparticles carrying poly(acrylic acid) brushes as a "CAT container" to increase enzyme loading for enhancing the detection signal. Under optimal conditions, the proposed pELISA exhibits good specificity and excellent sensitivity for L. monocytogenes with a LOD of 8 × 10(1) CFU/mL in 0.01 M phosphate-buffered saline, via a reaction that can be discriminated by the naked eye. The LOD obtained by this method was 2 and 5 orders of magnitude lower than that of conventional CAT-based pELISA and horseradish peroxidase (HRP)-based conventional ELISA, respectively. Coupled with large-volume immunomagnetic separation, the LOD for L. monocytogenes-spiked lettuce samples reached 8 × 10(1) CFU/g. The improved pELISA also exhibited a great potential in detecting a single cell of L. monocytogenes in 100 μL of solution.

In this work, a specific, sensitive, and accurate technique was presented for simultaneous detection of Salmonella spp., Shigella spp., and Staphylococcus aureus in food products, three of the more frequent foodborne pathogens that were usually reported in a variety of food matrices. An internal amplification control (IAC) was added in a multiplex PCR (mPCR) reaction system as an indicator of false negative result that can come from the presence of PCR inhibitors in food products. In the presence of inhibitor, no signal would result for the target genes as well as the IAC which results in a positive signal, thereby, eliminating false negative results. To ensure detection of only the viable cells, the effects of sodium deoxycholate (SD) in combination with propidium monoazide (PMA) treatment in the presence of dead cells and viable cells were investigated. Results showed that PMA treatment alone could not effectively inhibit the detection of 10 7 CFU/mL of dead Salmonella Typhimurium , Shigella sonnei , and S. aureus from PCR amplification. However, the SD in combination with PMA treatment gave negative results for PCR amplification of dead S. Typhimurium, S. sonnei, and S. aureus in pure culture and food products. When the developed SD-PMA-mPCR assay in combination with IAC was applied to detect the spiked food (milk, ground beef), the LOD of SD-PMA-mPCR assay for S. Typhimurium , S. sonnei, and S. aureus inoculated individually or inoculated simultaneously into milk or ground beef were 10 1 CFU/mL or 10 1 CFU/g after 15 h enrichment. The results suggested that the SD-PMA-mPCR assay in combination with IAC held promise for the detection of foodborne S. Typhimurium, S. sonnei, and S. aureus.

In this study, we established a novel polymerase chain reaction-hybridization chain reaction (PCR-HCR) dual signal amplification assay for sensitive detection of Escherichia coli O157:H7 in milk. In this assay, a blocker forward primer and a biotin reverse primer based on E. coli O157:H7 specific fliCh7 gene were specifically designed for PCR amplification resulting in a single-double stranded DNA with biotin (ss-dsDNA~biotin). These PCR products, ss-dsDNA~biotin, were captured by magnetic beads (MBs) decorated with streptavidin (SA) forming the ss-dsDNA~biotin+SA~MBs. The ssDNA on the PCR products opened the hairpin probe (H1 and H2) to trigger the HCR for secondary signal amplification. This is the first to use HCR to directly amplify PCR products through a novel blocker primer. With the help of two nucleic acid dual signal amplification techniques, PCR-HCR analysis can effectively improve the detection sensitivity and the limit of detection is 7.2 × 101 CFU/mL. In addition, this assay has been successfully used to detection target bacteria in skim milk spiked samples.

To improve the stability and enable luminescent devices, colloidal perovskite nanocrystals (NCs) are usually encapsulated by polymer host matrices. Here, colloidal CsPbX3 (X = Cl, Br or I, or mixture) NCs with bright emissions covering wide color gamut (~410–700 nm) are incorporated into the off-stoichiometry thiol-ene (OSTE) for solid state luminescence. The impact of polymer encapsulation on electronic transitions is investigated by comparison of absorption, photoluminescence (PL), and time resolved PL (TRPL) of the CsPbX3 NCs before and after the encapsulation by the OSTE. The PL bandwidth increase pronouncedly, while the PL peak position apparently blue shifts after encapsulation. The spectral changes suggest the energy transfer between the CsPbX3 NCs and OSTE matrix and decreased exciton binding energy due to the suppressed dielectric screen effect, which are further validated by the TRPL results. This work sheds light on the fluorescence of CsPbX3 NCs incorporated in the polymer host matrices, which will facilitate their future applications in light-emitting and other optoelectronic devices.

Listeria monocytogenes (L. monocytogenes) is a foodborne pathogen which can cause significant threats to human health, thus, a highly specific and accurate method for detection in food is urgently needed. In this study, an enzyme-linked aptasensor with rolling circle amplification (ELARCA) assay was developed for the sensitive and specific detection of L. monocytogenes. The assay was based on the competition between the aptamer (that was specific for L. monocytogenes) that was bound to the biotin probe 1 (BP1~A) and the RCA probe that was complementary to the BP1. Addition of the bacteria released the BP1 making it available for the RCA probe which initiated the RCA process. In the presence of the RCA buffer, multiple copies of the DNA were formed which attached the biotin probe 3 (BP3). The biotin in BP3 interacted with streptavidin labeled with horse radish peroxidase (SA-HRP) to complete the assay complex. In the presence of the enzyme substrate, HRP produced a chromophore that led to the colorimetric detection. Under the optimal conditions, the ELARCA assay for L. monocytogenes showed a limit of detection (LOD) of 4.6 × 102 CFU/mL in pure culture, which was three orders of magnitude higher than without RCA. The ELARCA assay in spiked fresh lettuce showed an LOD of 6.1 × 103 CFU/g. The method developed was fast, low-cost, sensitive, and highly specific for L. monocytogenes. By changing the specificity of the aptamer, the proposed ELARCA method provided a potential platform for the detection of other pathogenic bacteria.

We study the transport properties of the silicene nanoribbons subject to periodically driving electric and exchange fields. The multiple barriers made up of corresponding fields reshape the DC conductance by imposing pronounced both Fabry-Perot- and Fano-type resonances accompanied with high spin polarizations. In particular, a transport gap can be generated by the electric barriers with an appropriate strength, which is absent in the case of the barriers of the exchange field. The effects of the hybrid barriers including both electric and exchange fields, however, are not simply a mixture of two individual barriers, while depend on the relative phase of the time-varied barriers. In contrast to static barriers, the further studies of the driving frequency indicate that the in-gap states can survive in the transport gap for electric barriers as the frequency increases. This feature is particularly valuable for building spin-filter or spin-switcher devices.

Various surface modifications of iron oxide magnetic nanoparticles (IOMNs) can improve their stability and long-term retention time in vivo, expanding applications of biomedical fields. However, whether the long-term retention of IOMNs coated with different surface modifications has toxic effects remains poorly understood. Here, the toxicity of IOMNs modified with polyethylene glycol (PEG), bovine serum albumin (BSA), and carboxyl group (COOH), forming PEG-IOMNs, BSA-IOMNs, and COOH-IOMNs, respectively, were evaluated in the rats. The high accumulation of PEG-IOMNs and COOH-IOMNs both in the liver and lung, and the high accumulation BSA-IOMNs in blood after 24 day recovery were observed by elemental content analysis. Except individual neutrophils in the local portal area, PEG-IOMNs can also induce cytoplasmic vacuolisation in partial liver cells by histopathological examination. Furthermore, the results of RT-qPCR showed that PEG-IOMNs, BSA-IOMNs, and COOH-IOMNs can change the transcript levels of most genes related to iron homeostasis, mitochondria apoptosis, inflammatory response, but

The electronic structure and the persistent current of the hexagonal MoS2 quantum rings are investigated within the multi-orbital tight-binding formalism. It is shown that the degenerate energy levels split owing to spin-orbit coupling of Mo and S atoms, especially for the highest occupied state. The energy levels show the periodic oscillation with the increase of perpendicular magnetic flux. The spin-up electrons induced by magnetic flux flow clockwise around the rings resulting in paramagnetism. However, the spin-down electrons flow anticlockwise around the rings resulting in diamagnetism. Thus the hexagonal MoS2 quantum rings exhibit paramagnetic or diamagnetic effect, which is the result of competition of spin-up and spin down states.

Escherichia coli O157:H7 is a kind of waterborne pathogen and recognized as a common pathogenic microorganism in irrigation water. In this study, a quantitative PCR (qPCR) assay with propidium monoazide (PMA) treatment called PMA-qPCR assay was developed to detect the presence of E. coli O157:H7 in natural irrigation water that was more specific, more sensitive, and was unaffected by dead cells compared with traditional and conventional methods. Specific gene, fliC from E. coli O157:H7 was selected to design the unique primer and probe for the assay while propidium monoazide (PMA) was used to effectively prevent the interference of DNA from dead cells. Evaluation of the effect of PMA treatment exhibited permeation of the dead cell membranes that was observed under confocal laser scanning microscope (CLSM). The PMA-qPCR assay efficiently detected viable cells even in the presence of 104 CFU/mL dead cells. Under optimized conditions the limit of detection for viable cells was 102 CFU/mL or 10 CFU/mL in pure culture and spiked irrigation water in a 3 h assay. The PMA-qPCR assay did not show significant difference in the absence of the dead bacteria indicating specificity and selectivity for viable E. coli O157:H7. The PMA-qPCR assay developed in this study has potential for precise and sensitive detection of viable E. coli O157:H7 in irrigation water.

Dairy-related food safety outbreaks, such as food-borne pathogen contamination, mycotoxin contamination, and veterinary drug contamination, sometimes happen and have been reported all over the world, affecting human health and, in some cases, leading to death. Thus, rapid yet robust detection methods are needed to monitor milk and milk powder for the presence of hazardous substances. The lateral flow immunoassay (LFI) is widely used in onsite testing because of its rapidity, simplicity, and convenience. In this review, we describe some traditional LFI used to detect hazardous substances in milk and milk powder. Furthermore, we discuss recent advances in LFI that aim to improve sensitivity or detection efficiency. These advances include the use of novel label materials, development of signal amplification systems, design of multiplex detection systems, and the use of nucleic acid-based LFI.

Studies regarding circulating tumor cells (CTCs) have great significance for cancer prognosis, treatment monitoring, and metastasis diagnosis. However, due to their extremely low concentration in peripheral blood, isolation and enrichment of CTCs are the key steps for early detection. To this end, targeting the folic acid receptors (FRs) on the CTC surface for capture with folic acid (FA) using bovine serum albumin (BSA)-tether for multibiotin enhancement in combination with streptavidin-coated magnetic nanoparticles (MNPs-SA) was developed for ovarian cancer CTC isolation. The streptavidin-biotin-system-mediated two-step binding strategy was shown to capture CTCs from whole blood efficiently without the need for a pretreatment process. The optimized parameters for this system exhibited an average capture efficiency of 80%, which was 25% higher than that of FA-decorated magnetic nanoparticles based on the one-step CTC separation method. Moreover, the isolated cells remained highly viable and were cultured directly without detachment from the MNPs-SA-biotin-CTC complex. Furthermore, when the system was applied for the isolation and detection of CTCs in ovarian cancer patients' peripheral blood samples, it exhibited an 80% correlation with clinical diagnostic criteria. The results indicated that FA targeting, in combination with BSA-based multibiotin enhancement magnetic nanoparticle separation, is a promising tool for CTC enrichment and detection of early-stage ovarian cancer.

The in vivo toxicity of QDs in animals has been broadly studied; however, their reproductive toxicity towards lactating rodents is currently unknown. This study therefore aims to assess the potential toxicity against dams and offspring after postnatal QD exposure at two doses (5 and 1 nmol per rat) and unravel whether QDs can translocate to pups via breastfeeding. The dose-dependent systemic toxicity of QDs in dams was observed by examining the body weight, hematology, biochemistry, histopathological changes, and sex hormone levels. It was found that the QDs primarily accumulated in the liver and spleen of dams at 1 day post injection (dpi), but the highest concentrations were found in the kidneys at 18 dpi. A few QDs were detected in breast milk and stomach and intestine of pups; this suggested that the QDs were transmitted to breast milk via blood circulation and then transferred to pups via breastfeeding. High-dose QDs induced severe growth inhibition and a 71.08% offspring mortality, while pups showed growth restriction within 90 dpi in the low-dose group. Moreover, the hematology, biochemistry, and histology results showed limited chronic toxicity against offspring in the long term. This study provides a theoretical foundation for the exposure assessment of nanomaterials in lactating animals and for the advancement of QDs in the biomedical field.

Increasing evidence suggests that Enterococcus faecalis strains can pass through placental barriers and cause adverse outcomes during pregnancy. However, the underlying molecular mechanism of the interaction between E. faecalis and the host placental barrier has yet to be fully elucidated. In this study, we have used DNA microarray analysis to investigate the response of human placental trophoblast-like BeWo cells to infection with E. faecalis OG1RF. These results indicate that a total of 2191 genes in BeWo cells are differentially expressed in the presence of E. faecalis OG1RF, with 1357 genes being upregulated and 834 genes being downregulated. These differentially expressed genes (DEGs) are involved in apoptosis, stress and stimulus response, placental and embryonic development, immune response, and cell adhesion. Therefore, these results provide information on the molecular mechanisms that E. faecalis invasion can trigger to cause adverse pregnancy outcomes.

Infectious diseases caused by Listeria monocytogenes pose a great threat to public health worldwide. Therefore, a rapid and efficient method for L. monocytogenes detection is needed. In this study, a biotin-exposure-based immunomagnetic separation (IMS) method was developed. That is, biotinylated antibody was first targeted to L. monocytogenes. Then, streptavidin-functionalized magnetic nanoparticles were added and anchored onto L. monocytogenes cells indirectly through the strong noncovalent interaction between streptavidin and biotin. Biotin-exposure-based IMS exhibited an excellent capability to enrich L. monocytogenes. Specifically, more than 90% of L. monocytogenes was captured when the bacterial concentration was lower than 104 colony-forming units (CFU)/mL. Importantly, the antibody dosage was reduced by 10 times of that in our previous study, which used antibody direct-conjugated magnetic nanoparticles. Propidium monoazide (PMA) treatment prior to PCR amplification could eliminate the false-positive results from dead bacteria and detected viable L. monocytogenes sensitively and specifically. For viable L. monocytogenes detection, enriched L. monocytogenes was treated with PMA prior to asymmetric PCR amplification. The detection limits of the combined IMS with nucleic acid lateral flow (NALF) biosensor for viable L. monocytogenes detection were 3.5 × 103 CFU/mL in phosphate buffer solution and 3.5 × 104 CFU/g in lettuce samples. The whole assay process of recognizing viable L. monocytogenes was completed within 6 h. The proposed biotin-exposure-mediated IMS combined with a disposable NALF biosensor platform posed no health risk to the end user, and possessed potential applications in the rapid screening and identification of foodborne pathogens.