PI3K/Akt/FoxO Pathway Mediates Antagonistic Toxicity in HepG2 Cells Coexposed to Deoxynivalenol and Enniatins.

The emerging mycotoxins enniatins (ENNs) and the traditional mycotoxin deoxynivalenol (DON) often co-contaminate various grain raw materials and foods. While the liver is their common target organ, the mechanism of their combined effect remains unclear. In this study, the combined cytotoxic effects of four ENNs (ENA, ENA1, ENB, and ENB1) with DON and their mechanisms were investigated using the HepG2 cell line. Additionally, a population exposure risk assessment of these mycotoxins was performed by using in vitro experiments and computer simulations. The results showed that only ENA at 1/4 IC50 and ENB1 at 1/8 IC50 coexposed with DON showed an additive effect, while ENB showed the strongest antagonism at IC50 (CI = 3.890). Co-incubation of ENNs regulated the signaling molecule levels which were disrupted by DON. Transcriptome analysis showed that ENB (IC50) up-regulated the PI3K/Akt/FoxO signaling pathway and inhibited the expression of apoptotic genes (Bax, P53, Caspase 3, etc.) via phosphorylation of FoxO, thereby reducing the cytotoxic effects caused by DON. Both types of mycotoxins posed serious health risks, and the cumulative risk of coexposure was particularly important for emerging mycotoxins.

Double phage displayed peptides co-targeting-based biosensor with signal enhancement activity for colorimetric detection of Staphylococcus aureus.

The development of simple, fast, sensitive, and specific strategies for the detection of foodborne pathogenic bacteria is crucial for ensuring food safety and promoting human health. Currently, detection methods for Staphylococcus aureus still suffer from issues such as low specificity and low sensitivity. To address this problem, we proposed a sensitivity enhancement strategy based on double phage-displayed peptides (PDPs) co-targeting. Firstly, we screened two PDPs and analyzed their binding mechanisms through fluorescent localization, pull-down assay, and molecular docking. The two PDPs target S. aureus by binding to specific proteins on its outer membrane. Based on this phenomenon, a convenient and sensitive double PDPs colorimetric biosensor was developed. Double thiol-modified phage-displayed peptides (PDP-SH) enhance the aggregation of gold nanoparticles (AuNPs), whereas the specific interaction between the double PDPs and bacteria inhibits the aggregation of AuNPs, resulting in an increased visible color change before and after the addition of bacteria. This one-step colorimetric approach displayed a high sensitivity of 2.35 CFU/mL and a wide detection range from 10-2 × 108 CFU/mL. The combination with smartphone-based image analysis improved the portability of this method. This strategy achieves the straightforward, highly sensitive and portable detection of pathogenic bacteria.

Exploring the impact of fungal spores from agricultural environments on the mice lung microbiome and metabolic profile.

Exposure to particulate matter (PM) from agricultural environments has been extensively reported to cause respiratory health concerns in both animals and agricultural workers. Furthermore, PM from agricultural environments, containing fungal spores, has emerged as a significant threat to public health and the environment. Despite its potential toxicity, the impact of fungal spores present in PM from agricultural environments on the lung microbiome and metabolic profile is not well understood. To address this gap in knowledge, we developed a mice model of immunodeficiency using cyclophosphamide and subsequently exposed the mice to fungal spores via the trachea. By utilizing metabolomics techniques and 16 S rRNA sequencing, we conducted a comprehensive investigation into the alterations in the lung microbiome and metabolic profile of mice exposed to fungal spores. Our study uncovered significant modifications in both the lung microbiome and metabolic profile post-exposure to fungal spores. Additionally, fungal spore exposure elicited noticeable changes in α and ß diversity, with these microorganisms being closely associated with inflammatory factors. Employing non-targeted metabolomics analysis via GC-TOF-MS, a total of 215 metabolites were identified, among which 42 exhibited significant differences. These metabolites are linked to various metabolic pathways, with amino sugar and nucleotide sugar metabolism, as well as galactose metabolism, standing out as the most notable pathways. Cysteine and methionine metabolism, along with glycine, serine and threonine metabolism, emerged as particularly crucial pathways. Moreover, these metabolites demonstrated a strong correlation with inflammatory factors and exhibited significant associations with microbial production. Overall, our findings suggest that disruptions to the microbiome and metabolome may hold substantial relevance in the mechanism underlying fungal spore-induced lung damage in mice.

Rapid generation of high-quality recombinant antibodies using an Expi293F expression system for a 17 ß-estradiol immunoassay.

The rapid generation of high-quality target antibodies is essential for research employing immunoassays. The use of recombinant antibody technology that relies on genetic engineering is one such means to produce high-quality antibodies. Obtaining the gene sequence information of immunoglobulin is a prerequisite for the preparation of genetically engineered antibodies. At present, many researchers have shared their amino acid sequence data for various high-performance antibodies and their related properties. In this study, we obtained the protein sequence of a variable region of a 17 ß-estradiol (E2) antibody from the Protein Data Bank (PDB) and subsequently constructed heavy (H) and light (L) chain expression vectors through codon optimization. The transient expression, purification, and performance identification of the immunoglobulin G (IgG), antigen-binding fragment (Fab), and single-chain variable fragment (scFv) antibodies were carried out, respectively. The effects of the different expression vectors on the expression yield of the IgG antibody were further compared. Among them, the expression yield based on the pTT5 vector was the highest, reaching 27 mg/L. Based on the expressed IgG and Fab antibodies, an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) standard curve of E2 was constructed, and the half-maximal inhibitory concentrations (IC50) for these two antibodies were determined to be 0.129 ng/mL and 0.188 ng/mL, respectively. In addition, an immunochromatographic assay (ICA) based on the IgG antibody was constructed with an IC50 of 3.7 ng/mL. Therefore, in featuring the advantages of simplicity, high efficiency, rapid obtainment, and high titer yield, we propose the system for the rapid generation of high-quality recombinant antibodies by reusing the published antibody information and show that it has good implementation prospects in improving upon existing immunoassay techniques.

Metabolic pathway-based self-assembled Au@MXene liver microsome electrochemical biosensor for rapid screening of aflatoxin B1.

Cytochrome P450 enzymes (CYPs) catalyze the production of aflatoxin B1 (AFB1) metabolites, which play an important role in carcinogenesis. In this study, we report a simple electrochemical liver-microsome-based biosensor using a composite of gold nanoparticles adsorbed on MXene (Au@MXene) for rapid screening of AFB1. Rat liver microsomes (RLMs) were directly adsorbed on the Au@MXene nanocomposite. The high conductivity, large specific surface area, and good biocompatibility of the Au@MXene nanocomposite enabled the direct electron transfer between the RLMs and the electrode and maintained the biological activity of the enzyme in the RLMs to a large extent. The metabolic behavior of the RLM biosensor that was developed for the electrocatalyst of AFB1 to its hydroxylation metabolite aflatoxin M1 (AFM1) was confirmed. Based on the change in the electrical signal generated by this metabolic behavior, we established the relationship between AFB1 content and amperometric (I-t) current signal. When the AFB1 concentration ranged from 0.01 µM to 50 µM, the AFB1 concentration was linearly related to the electrical signal with a limit of detection of 2.8 nM. The results of the recovery experiments for corn samples showed that the recovery and accuracy of the sensor were consistent with the UPLC-MS/MS method.

Cell-Based Metabolomics Approach for Anticipating and Investigating Cytotoxicity of Gold Nanorods.

Despite the increasing application of gold nanoparticles, there has been little assessment of biological system toxicity to evaluate their potential impact on human health. In this study, the human hepatoma cell line (Hep G2) was used in a metabolomics approach to study the effects of shape, time, and dose of gold nanorods (GNRs). Using optimized parameters for chromatography and mass spectrometry, the metabolites detected by GC-MS were processed with MS DIAL and identified with Fiehnlib. Key metabolic pathways affected by GNRs were identified by endo-metabolic profiling of cells mixed with GNRs of varying shape while varying the dose and time of exposure. The shape of GNRs affected cytotoxicity, and short GNR (GNR-S) triggered disorder of cell metabolism. High concentrations of GNRs caused more significant toxicity. The cytotoxicity and bioTEM results illustrated that the mitochondria toxicity, as the main cytotoxicity of GNRs, caused declining cytoprotective ability. The mitochondrial dysfunction disrupted alanine, aspartate, glutamate, arginine, and proline metabolism, with amino acid synthesis generally downregulated. However, the efflux function of cells can exclude GNRs extracellularly within 24 h, resulting in reduced cell mitochondrial metabolic toxicity and allowing metabolic disorders to recover to normal function.

Microbial detoxification of mycotoxins in food and feed.

Mycotoxins are metabolites produced by fungi growing in food or feed, which can produce toxic effects and seriously threaten the health of humans and animals. Mycotoxins are commonly found in food and feed, and are of significant concern due to their hepatotoxicity, nephrotoxicity, carcinogenicity, mutagenicity, and ability to damage the immune and reproductive systems. Traditional physical and chemical detoxification methods to treat mycotoxins in food and feed products have limitations, such as loss of nutrients, reagent residues, and secondary pollution to the environment. Thus, there is an urgent need for new detoxification methods to effectively control mycotoxins and treat mycotoxin pollution. In recent years, microbial detoxification technology has been widely used for the degradation of mycotoxins in food and feed because this approach offers the potential for treatment with high efficiency, low toxicity, and strong specificity, without damage to nutrients. This article reviews the application of microbial detoxification technology for removal of common mycotoxins such as Aflatoxin, Ochratoxin, Zearalenone, Deoxynivalenol, and Fumonisins, and discusses the development trend of this important technology.

Universal fluorescence nanoprobes to enhance the sensitivity of immunochromatographic assay for detection of 17ß-estradiol in milk.

The pollution caused by estrogens in the environment and food has received increasing attention. It is still challenging for on-site immunochromatographic assay (ICA) detection of estrogens. The performance of the prepared probes plays a decisive role in the sensitivity and stability of the ICA system. The published probes usually directly couple the detection antibody to the label, ignoring the influence of the label on the activity of the antibody. In this study, 17ß-estradiol (E2) was used as a model analyte for the ICA system. Two universal probes were constructed based on quantum dot nanobeads (QBs), recombinant protein A (SPA, from Staphylococcus aureus), and rabbit anti-mouse immunoglobulin G antibody (anti-IgG). The probes were prepared by coupling QBs with SPA, releasing anti-E2 monoclonal antibody (mAb), and maintaining its activity. The prepared universal probes can orient recognize the Fc region of mAb and fully expose its Fab region, improving the detection sensitivity of the ICA system. The free anti-E2 mAb and the universal probe (QBs@SPA or QBs@SPA@anti-IgG) were used as the detection antibodies and signal donors, respectively. The results show that the proposed ICA based on QBs@SPA and QBs@SPA@anti-IgG probes could detect E2 with IC50 of 8.83 and 0.93 ng/mL, respectively, within 15 min under optimal conditions. The recovery results of ICA based on QBs@SPA and QBs@SPA@anti-IgG probes showed good agreement with the findings of the high-performance liquid chromatography (HPLC) analysis for spiked samples. The developed ICA system based on universal probes was superior in terms of sensitivity, rapidity, and applicability, and held great promise for its implementation in detecting environmental and food small-molecule pollutants.

Development of a living mammalian cell-based biosensor for the monitoring and evaluation of synergetic toxicity of cadmium and deoxynivalenol.

With increased interest in the toxic interactions of multiple toxins, biotoxicity models have to be urgently developed for joint toxicity evaluation. This study aimed to develop an optical biosensor based on living mammary cells for monitoring of cadmium (Cd)/deoxynivalenol (DON) in water and evaluating their combined toxicity. Our previous survey found that DON and Cd appeared simultaneously in various products, and RNA seq revealed that AP-1 participated in combined toxicity of DON+Cd in HT-29 cells. Thus AP-1 site-mCherry-based biosensors were constructed, optimized, and then tested for their applicability and stable fluorescence response activities. DON+Cd2+, DON, and Cd2+ induced dose-dependent fluorescence signal in the biosensors (at environmental exposure levels). The enhanced fluorescence signal suggested that the toxicity of DON+Cd2+ was enhanced compared with that of single toxin. The advantages of the biosensors include: I) The easy and visual screening of multiple toxins on the basis of environmental exposure levels; II) Potential as a broad-spectrum tool for joint toxicity evaluation of DON+Cd; III) Pollution-free and stable fluorescence response; IV) A slight effect on viability.

Highly sensitive real-time detection of intracellular oxidative stress and application in mycotoxin toxicity evaluation based on living single-cell electrochemical sensors.

Single-cell electrochemical sensor is widely used in the local selective detection of single living cells because of its high spatial-temporal resolution and sensitivity, as well as its ability to obtain comprehensive cellular physiological states and processes with increased accuracy. Functionalized nanoprobes can detect the oxidative stress response of cells in single-cell electrochemical sensors. Moreover, the T-2 toxin is one of the most toxic mycotoxins and widely occurs in field crops. T-2 toxin can cause mitochondrial damage in cells and increase intracellular reactive oxygen species (ROS) in various cells. As the most representative free radical of intracellular ROS, H2O2 can effectively reflect the toxic effects of intracellular T-2 toxin. In this study, a functionalized gold nanoprobe was used to dynamically monitor the production of H2O2 in a single live human hepatoma cell HepG2 stimulated by mycotoxin T-2. The concentration of H2O2 produced by HepG2 cells stimulated by T-2 toxin at 1 ppb-1 ppm was linearly correlated, R2 = 0.99055, and LOD = 0.13807 ng mL-1. Sample spiking experiments were conducted, and the recovery rate of spiking was 81.19%-130.17%. A comparative analysis of differences in the current produced by multiple toxins, HT-29 cells, as well as single cells in cell populations, was performed. This method can be applied in real-time monitoring of mycotoxin toxicity during food processing in living cells and provides a novel idea for enhancing food quality and safety in a nanoenvironment.

Opposite estrogen effects of estrone and 2-hydroxyestrone on MCF-7 sensitivity to the cytotoxic action of cell growth, oxidative stress and inflammation activity.

There are many kinds of estrogens, and endogenous estrogens produce a variety of estrogen metabolites with similar structure but with different physiological effects after metabolism in vivo. Studies have shown that estrone (E1) widely occurs in the environment and animal-derived food. Because of its estrogen effect, E1 can have adverse effects on the human body as an endocrine disruptor. In this study, we found that E1 and 2-hydroxyestrone (2-OH-E1), the hydroxylation metabolite of estrogen, have opposite proliferative effects on breast cancer cells (MCF-7) through cell proliferation experiments and comparison of their effects by molecular docking and detection of ROS, Ca2+, and cell pathway proteins. The effects of 2-methoxyestrone (2-MeO-E1) and 16α-hydroxyestrone (16α-OH-E1) on the biochemical and protein levels of MCF-7 were further studied to compare the effects of metabolic sites and modes on estrogen effects. Hydroxylation of E1 at the C2 site weakened the estrogen effect, down-regulated the expression of the mammalian target of rapamycin (mTOR) and protein kinase B (Akt) pathway proteins, inhibited the proliferation of cancer cells, and enhanced anti-oxidative stress and anti-inflammation. Methoxylation at the C2 position also inhibited the expression of inflammatory and oxidative stress pathway proteins but did not greatly affect the estrogen effects. However, hydroxylation on C16 had no significant effect on the biological effects of estrogen. Therefore, the structural changes of estrogen on C2 are important reasons for the different physiological effects of estrogen and its metabolites. Thus, by regulating the gene Cytochrome P450 1B1(CYP1B1), which affects the hydroxylation metabolism of estrogen, and promoting the hydroxylation of estrone at the C2 position, the estrogen effect of estrone can be effectively reduced, thus reducing the harm its poses in food and the environment.

MAPK/AP-1 and ROS participated in ratio- and time-dependent interaction effects of deoxynivalenol and cadmium on HT-29 cells.

Deoxynivalenol (DON) and cadmium (Cd) not only share target organs, but also share certain upstream and downstream toxic pathways. DON and Cd may accumulate in the food chain, increasing the risk of joint exposure. Therefore, there is a significant need to characterize the joint toxicity of these two compounds. The goal of this work was to investigate the toxic trends and interaction effects of DON and CdCl2 on HT-29 cells, and uncover a role of the MAPK/AP-1 and oxidative stress pathways. The experiment was designed based on the average exposure situation in real life (DON: CdCl2, ppm: ppm, 1.62:1) and commonly used designs in toxicology research (IC50: IC50, 12/24/48 h). We observed time-, and ratio-dependent toxicity and joint effects in mixtures of CdCl2 and DON. At the plausible intestinal level, the ratio of IC50: IC50 transitioned from synergism to antagonism with increased exposure time, while the other ratio showed differential behavior. Long-term or low-dose exposure mainly resulted in antagonism, while short-term or high-dose treatment mainly resulted in synergism. The change trends of MAPK/AP-1 and oxidative stress were consistent with the cytotoxicity trend, and activation of AP-1 was confirmed by transfection assay.

Microfluidic-based fluorescent electronic eye with CdTe/CdS core-shell quantum dots for trace detection of cadmium ions.

Cadmium ions (Cd2+) greatly threat human health and the environment due to its extremely severe toxicity. Therefore, it is of paramount importance to establish a sensitive and portable platform for monitoring Cd2+ on site. In this work, a novel microfluidic-based fluorescent electronic eye (E-eye) combined with tetrasodium iminodisuccinate (IDS)-etched CdTe/CdS quantum dots (QDs) was developed for portable and sensitive detection of trace Cd2+ in water environment. The fluorescent E-eye consists of a microfluidic chip for miniaturized flow analysis, an ultraviolet light excitation module for fluorescent excitation, an optical lens for device miniaturization and a smartphone for portable photographing and analysis. The IDS was added in the CdTe/CdS QDs to cause fluorescence quenching due to the chemical etching. Subsequently added Cd2+ will be recognized by etched QDs, thus inducing the fluorescence changes that can be directly captured by the E-eye for quantitative detection of Cd2+. With the optimization of all parameters including pH, reaction time and the concentration of IDS, the proposed platform could detect Cd2+ with a low detection limit of 0.26 µg/L in the range of 1-250 µg/L. It is worth noting that the performance of the developed fluorescent E-eye is quite comparable to a commercial microplate reader with a detailed comparison in linearity, sensitivity and detection limit. In summary, the proposed microfluidic-based fluorescent E-eye provides a promising platform for portable and high sensitive detection of trace cadmium in water environment.

A novel portable biosensor based on aptamer functionalized gold nanoparticles for adenosine detection.

Adenosine has received great attentions acting as a potential biomarker for monitoring lung cancer. Most of the reported studies for adenosine detection require large instruments and complicated procedures. Herein, a sensitive, rapid and in-situ colorimetric aptasensor was developed for adenosine detection. Moreover, a homemade biomimetic electronic-eye (E-eye) was established and utilized as a portable in-time detection equipment. The entire measurement can be completed within 20 min, including the combination of aptamer with adenosine or AuNPs and the detection of adenosine. Four different kinds of aptamer were compared and the results showed that the AuNPs-aptamer-biotin system was the most stable and with the widest detection range of 5.0 µM-60.0 µM and the lowest LOD of 0.17 µM. Moreover, the artificial urine samples were also tested with a linear range from 5.0 to 50.0 µM and a LOD of 0.48 µM. The results validated that the aptasensor together with the E-eye can be a promising platform for adenosine detection.

Ultrasensitive Fluorometric Angling Determination of Staphylococcus aureus in Vitro and Fluorescence Imaging in Vivo Using Carbon Dots with Full-Color Emission.

Rapid, accurate, and safe screening of foodborne pathogenic bacteria is essential to effectively control and prevent outbreaks of foodborne illness. Fluorescent sensors constructed from carbon dots (CDs) and nanomaterial-based quenchers have provided an innovative method for screening of pathogenic bacteria. Herein, an ultrasensitive magnetic fluorescence aptasensor was designed for separation and detection of Staphylococcus aureus (S. aureus). Multicolor fluorescent CDs with a long fluorescent lifetime (6.73 ns) and high fluorescence stability were synthesized using a facile hydrothermal approach and modified cDNA as a highly sensitive fluorescent probe. CD fluorescence was quenched by Fe3O4 + aptamer via fluorescence resonance energy transfer (FRET). Under optimal conditions, the FRET-based aptasensor can detect S. aureus accompanied by a wide linear range of 50-107 CFU·mL-1 and a detection limit of 8 CFU·mL-1. Compared with other standard methods, this method was faster and more convenient, and the entire test was finished within 30 min. The capability of the aptasensor was simultaneously investigated on food samples. Additionally, the developed CDs exhibited excellent biocompatibility and were thus applied as fluorescent probes for bioimaging both in vitro and in vivo. This new platform provided an excellent application of the CDs for detecting and bioimaging pathogenic bacteria.

Red-Emissive Carbon Dots for "Switch-On" Dual Function Sensing Platform Rapid Detection of Ferric Ions and l-Cysteine in Living Cells.

Ferric ions (Fe3+ ions) and l-cysteine (( l-Cys) in the human body have always played an irreplaceable role in biological processes, and overload or deficiency of Fe3+ ions and l-Cys in the biological system leads to various diseases. In this work, N,S-co-doped red-emitting carbon dots (R-CDs) were synthesized by a facile hydrothermal method. Because the doping of N and S gives a unique functional group distribution on the surface of R-CDs, it can be complexed with Fe3+ ions to construct an energy transfer quenching system. However, the presence of l-Cys competitively binds to Fe3+ ions, thus resulting in the photoluminescence recovery of R-CDs. Therefore, a "switch-on" dual function sensing platform has successfully been developed based on R-CDs for rapid identification and quantification of Fe3+ ions and l-Cys. The linear detection range of Fe3+ ions is 0-30 µM (limit of detection (LOD): 0.27 µM) and that of l-Cys is 0-24 µM (LOD: 0.14 µM). The sensor platform was used to detect Fe3+ ions and l-Cys in human serum samples with satisfactory results. Compared with traditional detection methods, this method is more time-saving and efficient and can be completed in 3 min. It is worth mentioning that the R-CDs not only has high optical stability but also has negligible cytotoxicity and has been successfully applied to in vitro/vivo imaging, indicating that R-CDs have excellent tissue penetration and biomarker potential. More interestingly, the switch-on fluorescence behavior for stepwise detection of Fe3+ ions and l-Cys can also be observed in cell imaging, which provides the possibility of visual detection of the probe to be applied in vivo.

Ultrasensitive fluorometric determination of iron(iii) and inositol hexaphosphate in cancerous and bacterial cells by using carbon dots with bright yellow fluorescence.

An ON-OFF-ON dual-function fluorescent nanoprobe is described for the trace detection of ferric ions and inositol hexaphosphate (IP6) in living cells. It is based on the use of yellow-fluorescent nitrogen-doped carbon dots (YN-CDs). Highly fluorescent YN-CDs were synthesized by a hydrothermal process. They have an absolute quantum yield of 2.15% and excitation/emission peaks at 420/575 nm. Fluorescence is quenched by Fe3+via photo-induced electron transfer. The quenchometric assay has a 34 nM detection limit for Fe(iii). On addition of IP6 which has a high affinity for Fe3+ due to the formation of Fe-O-P bonds, fluorescence becomes gradually restored. The resulting ON-OFF-ON assays for Fe(iii) and IP6 are reliable and sensitive. IP6 can be detected at concentrations as low as 2 nM. The nanoprobe was then applied to the determination of Fe3+ and IP6 in living cells in a food matrix. Furthermore, YN-CDs exhibited excellent biocompatibility. Hence, the probe can be applied as a fluorescent ink for bioimaging, both in vitro (cancer cells and bacteria) and in vivo (nematodes and mice).

A novel magnetic fluorescent biosensor based on graphene quantum dots for rapid, efficient, and sensitive separation and detection of circulating tumor cells.

We describe a "turn-on" magnetic fluorescent biosensor based on graphene quantum dots (GQDs), Fe3O4, and molybdenum disulfide (MoS2) nanosheets. It is used for rapid, efficient, and sensitive separation and detection of circulating tumor cells (CTCs). A facile approach (electrochemical synthesis method) for the preparation of photoluminescent GQDs functionalized with an aptamer [epithelial cell adhesion molecule (EpCAM) receptors] and a magnetic agent for one-step bioimaging and enrichment of CTCs is described. MoS2 nanosheets, as a fluorescence quencher, and the aforementioned aptamer@Fe3O4@GQD complex were assembled to construct "turn-on" biosensing magnetic fluorescent nanocomposites (MFNs). This system exhibits low cytotoxicity and an average capture efficiency of 90%, which is higher than that of other magnetic nanoparticles on account of the one-step CTC separation method. In addition, the MFNs could quickly identify and label CTCs within 15 min, surpassing other one-step and two-step marker detection methods. Furthermore, because of the presence of aptamers, the MFNs have specific capability to capture CTCs (both low- and high-EpCAM-expressing cells). In addition, high-sensitivity detection of up to ten tumor cells in whole blood was achieved. Therefore, the MFNs have great potential to be used as universal biosensing nanocomposites for fluorescence-guided tumor cell enrichment and bioimaging. Graphical abstract ᅟ.

Ultrasensitive "FRET-SEF" Probe for Sensing and Imaging MicroRNAs in Living Cells Based on Gold Nanoconjugates.

MicroRNAs (miRNAs), a kind of single-stranded small RNA molecule, play significant roles in the physiological and pathological processes of human beings. Currently, miRNAs have been demonstrated as important biomarkers critically related to many diseases and life nature, including several cancers and cell senescence. It is valuable to establish sensitive assays for monitoring the levels of intracellular up-regulated/down-regulated miRNA expression, which would contribute to the early prediction of the tumor risk and cardiovascular disease. Here, an oriented gold nanocross (AuNC)-decorated gold nanorod (AuNR) probe with "OFF-enhanced ON" fluorescence switching was developed based on fluorescence resonance energy transfer and surface enhanced fluorescence (FRET-SEF) principle. The nanoprobe was used to specifically detect miRNA in vitro, which gave two linear responses represented by the equation F = 1830.32 log C + 6349.27, R2 = 0.9901, and F = 244.41 log C + 1916.10, R2 = 0.9984, respectively, along with a detection limit of 0.5 aM and 0.03 fM, respectively. Furthermore, our nanoprobe was used to dynamically monitor the expression of intracellular up-regulated miRNA-34a from the HepG2 and H9C2 cells stimulated by AFB1 and TGF-ß1, and the experimental results showed that the new probe not only could be used to quantitively evaluate miRNA oncogene in vitro, but also enabled tracking and imaging of miRNAs in living cells.

Metabolomics Analysis To Evaluate the Anti-Inflammatory Effects of Polyphenols: Glabridin Reversed Metabolism Change Caused by LPS in RAW 264.7 Cells.

Inflammation has been shown to play a critical role in the development of many diseases. In this study, we used metabolomics to evaluate the inflammatory effect of lipopolysaccharide (LPS) and the anti-inflammatory effect of glabridin (GB, a polyphenol from Glycurrhiza glabra L. roots) in RAW 264.7 cells. Multivariate statistical analysis showed that in comparison with the LPS group, the metabolic profile of the GB group was more similar to that of the control group. LPS impacted the amino acid, energy, and lipid metabolisms in RAW 264.7 cells, and metabolic pathway analysis showed that GB reversed some of those LPS impacts. Metabolomics analysis provided us with a new perspective to better understand the inflammatory response and the anti-inflammatory effects of GB. Metabolic pathway analysis can be an effective tool to elucidate the mechanism of inflammation and to potentially find new anti-inflammatory agents.