Ultrafast Ratiometric Detection of Aflatoxin B1 Based on Fluorescent ß-CD@Cu Nanoparticles and Pt2+ Ions.

Rapid detection of aflatoxin B1 (AFB1) is a very important task in food safety monitoring. However, it is still challenging to achieve highly sensitive detection without antibody or aptamer biomolecules. In this work, a rapid detection of aflatoxin B1 was achieved using a ratiometric fluorescence probe without antibody or aptamer for the first time. In the ratiometric fluorescence system, the fluorescence emission of AFB1 at 433 nm was significantly enhanced due to the ß-cyclodextrin-AFB1 host-guest interaction and the complexation of AFB1 and Pt2+. Meanwhile, the inclusion of aflatoxin B1 also quenched the fluorescence emission of ß-CD@Cu nanoparticles (NPs) at 650 nm based on inner filter effect mechanism. On the basis of the above effects, the ratiometric detection of aflatoxin B1 was achieved in the range of 0.03-10 ng/mL with a low detection limit of 0.012 ng/mL (3σ/s). In addition, the ß-CD@Cu NPs based nanoprobe could achieve stable response within 1 min to AFB1. The above ratiometric detection also demonstrated excellent application potential in the rapid on-site detection of AFB1 in food due to the advantages of convenience, rapidness, and high accuracy.

Mesoporous silica-loaded gold nanocluster with enhanced fluorescence and ratiometric fluorescent detection of thiram in foods.

A core-shell QDs@mSiO2@y-AuNCs nanoprobe was prepared, and a new ratiometric fluorescent sensor for thiram detection was developed. The mechanism of thiram sensing was investigated using FTIR, surface-enhanced Raman, XPS spectra, etc. The sensing of thiram was mainly ascribed to the formation of Au-S bonds between thiram and Au atoms on y-AuNCs surface, resulting in the dissociation of 11-MUA ligand from the y-AuNCs surface and the charge transfer between thiram and y-AuNCs. In the ratiometric fluorescence detection of thiram based on QDs@mSiO2@y-AuNCs, a linear range of 0.5-60 ng/mL was obtained with a LOD of 0.19 ng/mL. Compared with the fluorescence detection based on y-AuNCs, the ratiometric fluorescence detection of thiram demonstrated 3-fold enhanced sensitivity. The improvement was ascribed to two aspects: the fluorescence emission of y-AuNCs was enhanced after they were loaded onto the QDs@mSiO2 nanoparticles; the ratiometric detection mode provided more precise sensing. The detection of thiram can be completed immediately after mixing the nanoprobe with thiram. Good recoveries of thiram in apple and pear samples were achieved. All the above results demonstrated the high potential of this method in practical applications.

DNA dendrimer-templated copper nanoparticles: self-assembly, aggregation-induced emission enhancement and sensing of lead ions.

Copper nanomaterials based on DNA scaffold (DNA-Cu NMs) are becoming a novel fluorescent material, but it is still challenging to obtain highly fluorescent DNA-Cu NMs with excellent stability. In this work, we report a kind of copper nano-assemblies (Cu NASs) with aggregation-induced emission enhancement (AIEE) property using DNA dendrimers with sticky end as template. The sticky end of the DNA dendrimers induced the formation of much bigger Cu NASs with average size ranging from 131 to 264 nm, depending on the length of the DNA dendrimer sticky end from 6 bases to 27 bases. Compared with complete complementary DNA dendrimer, nearly 6-fold fluorescence enhancement was achieved using DNA dendrimer with 27 bases sticky end. Moreover, the DNA dendrimer-Cu NASs demonstrated excellent stability in serum and could be rapidly quenched by Pb2+ ions. Based on the above property, highly sensitive and selective fluorescent detection of Pb2+ ions was possible with a linear range of 2.0-100 nM and a detection limit of 0.75 nM. Due to the sensitive and rapid response to Pb2+ as well as excellent stability in complex matrix, the proposed fluorescent Cu NASs demonstrated high potential as an excellent fluorescent probe for Pb2+ in complex matrix.

Serum exosomal microRNA let-7i-3p as candidate diagnostic biomarker for Kawasaki disease patients with coronary artery aneurysm.

Kawasaki disease (KD) is a systemic vasculitis syndrome that leads to coronary artery aneurysm (CAA). While echocardiography is the most important imaging modality for coronary artery assessment, a specific diagnostic biomarker complementary for CAA has not been reported. We aimed to analyze the profiles of exosomal miRNAs extracted from the serum of KD patients and controls to identify candidate biomarkers for CAA. Serum samples from 39 healthy children, 42 CAA patients, 38 coronary artery dilatation (CAD) patients and 45 virus-infected patients including 24 EBV patients and 21 ADV patients were randomly selected. Next generation sequencing was used to analyze serum exosomal miRNA to detect differentially expressed miRNAs. Biomarker candidates were validated by qRT-PCR. One hundred (and) ninety-six differentially expressed miRNAs (DEMs) were detected in CAA patients and healthy children. There were 70 DEMs and 140 DEMs in CAA patients versus CAD patients, and in CAA patients versus virus-infected patients, respectively. We selected the three most upregulated (let-7i-3p, miR-17-3p, and miR-210-5p) and the three most downregulated miRNAs (miR-6743-5p, miR-1246, and miR-6834-5p) in the DEMs, which were expressed differentially in CAA patients versus healthy children, and in CAA patients versus virus-infected patients, not in virus-infected patients versus healthy children, as biomarker candidates. Excluded DEMs of CAD and virus-infected patients, let-7i-3p was detected by sequence data analysis as a biomarker candidate for CAA patients, and then validated by qRT-PCR in a larger set of clinical samples. As a biomarker candidate, let-7i-3p provides an additional means of diagnosing CAA patients. Additionally, miRNA biomarkers complement ultrasonic imaging, allowing for greater diagnostic precision. © 2019 IUBMB Life, 2019.

Proteomics study of serum exosomes in Kawasaki disease patients with coronary artery aneurysms.

BACKGROUND: To study the protein profile of the serum exosomes of patients with coronary artery aneurysms (CAA) caused by Kawasaki disease (KD). METHODS: Two-dimensional electrophoresis (2-DE) was used to identify proteins from the exosomes of serum obtained from children with CAA caused by KD, as well as healthy controls. Differentially expressed proteins were identified using matrix-assisted laser desorption/ionization time-of-flight/timeof-flight mass spectrometry (MALDI-TOF/TOF MS) analysis. RESULTS: Thirty two differentially expressed proteins were identified (18 up-regulated and 14 downregulated) from serum exosomes of children with CAA and were compared to healthy controls. The expression levels of 4 proteins (TN, RBP4, LRG1, and APOA4) were validated using Western blotting. Classification analysis and protein-protein network analysis showed that they are associated with multiple functional groups, including host immune response, inflammation, apoptotic process, developmental process, and biological adhesion process. CONCLUSIONS: These findings establish a comprehensive proteomic profile of serum exosomes from children with CAA caused by KD, and provide additional insights into the mechanisms of CAA caused by KD.

Differential protein analysis of serum exosomes post-intravenous immunoglobulin therapy in patients with Kawasaki disease.

BACKGROUND: Kawasaki disease, which is characterised by systemic vasculitides accompanied by acute fever, is regularly treated by intravenous immunoglobulin to avoid lesion formation in the coronary artery; however, the mechanism of intravenous immunoglobulin therapy is unclear. Hence, we aimed to analyse the global expression profile of serum exosomal proteins before and after administering intravenous immunoglobulin. METHODS: Two-dimensional electrophoresis coupled with mass spectrometry analysis was used to identify the differentially expressed proteome of serum exosomes in patients with Kawasaki disease before and after intravenous immunoglobulin therapy. RESULTS: Our analysis revealed 69 differential protein spots in the Kawasaki disease group with changes larger than 1.5-fold and 59 differential ones in patients after intravenous immunoglobulin therapy compared with the control group. Gene ontology analysis revealed that the acute-phase response disappeared, the functions of the complement system and innate immune response were enhanced, and the antibacterial humoral response pathway of corticosteroids and cardioprotection emerged after administration of intravenous immunoglobulin. Further, we showed that complement C3 and apolipoprotein A-IV levels increased before and decreased after intravenous immunoglobulin therapy and that the insulin-like growth factor-binding protein complex acid labile subunit displayed reverse alteration before and after intravenous immunoglobulin therapy. These observations might be potential indicators of intravenous immunoglobulin function. CONCLUSIONS: Our results show the differential proteomic profile of serum exosomes of patients with Kawasaki disease before and after intravenous immunoglobulin therapy, such as complement C3, apolipoprotein A-IV, and insulin-like growth factor-binding protein complex acid labile subunit. These results may be useful in the identification of markers for monitoring intravenous immunoglobulin therapy in patients with Kawasaki disease.

[Preparation, characterization and surface-enhanced Raman properties of agarose gel/gold nanoparticles hybrid].

Agarose gel/gold nanoparticles hybrid was prepared by adding gold nanoparticles to preformed agarose gel. Naniocomposite structures and properties were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and UV-Vis-NIR absorption spectroscopy. Experimental data indicated a uniform distribution of gold nanoparticles adsorbed on agarose gel network And the excellent optical absorption properties were shown. Based on the swelling-contraction characteristics of agarose gel and the adjustable localized surface plasmon resonance (LSPR) of the gold nanoparticles, the nano-composites were used as surface enhanced Raman scattering (SERS) substrate to detect the Raman signal molecules Nile blue A. Results revealed that the porous structure of the agarose gel provided a good carrier for the enrichment of the gold nanoparticles. The gold nanoparticles dynamic hot-spot effect arising from the agarose gel contraction loss of water in the air greatly enhanced the Raman signal.

Dyslipidemic high-fat diet affects adversely bone metabolism in mice associated with impaired antioxidant capacity.

OBJECTIVE: The present study examined impacts of dyslipidemic high-fat diet on the bone antioxidant system and bone metabolism in growing mice. Furthermore, the relationship was studied between them. METHODS: Male C57BL/6 mice (4 wk old) were fed with normal diet, high-fat diet (HFD), or HFD supplemented with 0.1% antioxidant lipoic acid (LA). After 13-wk feeding, the markers of plasma lipids status, bone metabolism in plasma and in urine, and femora oxidative stress were measured. To provide molecular evidence for abnormal bone metabolism affected by HFD, bone cell-specific mRNA levels were tested by real-time quantitative polymerase chain reaction. Moreover, insulin-like growth factor I and tumor necrosis factor-alpha in plasma and their mRNA levels in femur were measured. RESULTS: The feeding dyslipidemic HFD induced both inhibitory bone formation reactions and enhancement of bone resorption reactions, accompanied by impaired bone antioxidant system, low levels of insulin-like growth factor I in plasma and in bone, and high levels of tumor necrosis factor-alpha in plasma but not in bone. In contrast, these alternatives were prevented completely or partially in mice fed LA supplement. Further, plasma propeptide of І collagen C-propeptide as a marker of bone formation was positively correlated with both total antioxidant capacity (r=0.683, P<0.001) and reduced glutathione/oxidized glutathione ratio (r=0.565, P<0.003) of bone. Cross-linked N-telopeptides of bone type І collagen as a marker of bone resorption was negatively correlated with both total antioxidant capacity (r=-0.753, P<0.001) and glutathione/oxidized glutathione ratio (r=-0.786, P<0.001). CONCLUSION: Dyslipidemia induces impaired bone antioxidant system. Oxidative stress could be an important mediator of hyperlipidemia-induced bone loss.

Effects of duodenal redox status on calcium absorption and related genes expression in high-fat diet-fed mice.

OBJECTIVE: This study investigated whether duodenal redox imbalance induced by high-fat diet (HFD) influenced expression of genes involved in transcellular calcium absorption, thus leading to reduced intestinal calcium absorption. METHODS: Male C57BL/6 mice were randomly assigned to one of four groups with eight mice in each group. The control group consumed an ordinary diet (4.9% fat, w/w). The other three groups were fed a HFD (21.2% fat), the HFD plus 0.1% lipoic acid, or the HFD plus an additional 0.9% calcium supplement. After 9 wk, plasma and duodenal oxidative stress biomarkers including malondialdehyde, superoxide dismutase, catalase, total antioxidant capacity, reduced glutathione/oxidized glutathione ratio, and reactive oxygen species were examined. The intestinal calcium absorption state was evaluated through examining the calcium balance, bone mineral density, and calcium metabolism biomarkers. Furthermore, quantitative reverse transcription-polymerase chain reaction was carried out to analyze the changes in expression of transcellular calcium absorption-related genes. RESULTS: The HFD induced marked decreases in intestinal calcium absorption and bone mineral density of the whole body, accompanied by redox imbalance and increased oxidative damage in duodenum; duodenal expression of calbindin-D(9K), plasma membrane calcium ATPase (PMCA(1b)), and sodium-calcium exchanger was significantly down-regulated by 1.9-, 2.7-, and 1.5-fold, respectively. Furthermore, duodenal glutathione and oxidized glutathione (GSH/GSSG) ratios were strongly positively correlated with the apparent calcium absorption rate and the expression of PMCA(1b) and Calbindin-D(9K), whereas reactive oxygen species levels were negatively correlated with them. CONCLUSION: Our results demonstrated that a HFD-induced duodenal oxidation state could significantly down-regulate expression of calbindin-D(9K), PMCA(1b), and sodium-calcium exchanger, thus causing an inhibitory effect on intestinal calcium absorption.

[Effect of resveratrol on myocardial fibrosis in mice with chronic viral myocarditis].

OBJECTIVE: Some research has shown that resveratrol can ameliorate myocardial injury and improve cardiac function in mice with acute viral myocarditis (VMC), and can inhibit cardiac fibroblast proliferation and myofibroblast differentiation in vitro. This study was designed to investigate whether resveratrol has similar effects in the mouse model of chronic VMC. METHODS: One hundred mice were inoculated with 0.3 mL of Coxsackievirus B3 1*106 TCID50. Thirty days later, the survivors (n=62) were used as a model of chronic VMC, and were randomly assigned to 4 groups: untreated VMC, and low- (10 mg/kg), middle- (100 mg/kg) and high-dose (1 000 mg/kg) resveratrol-treated VMC (once daily, for 30 days). Ten mice which received neither Coxsackievirus B3 nor resveratrol treatment served as the control group. After 30 days of resveratrol treatment, the mice were sacrificed. Serum concentrations of collagenous pre-peptides (PINP, PICP and PIIINP) were assessed using ELISA. Hematoxylin-eosin staining, picrosirius red staining and circularly polarized light were used to examine the histochemistry of myocardial collagen. RESULTS: The myocardial collagen volume fraction in the high-dose (0.74+/-0.19) and the middle-dose (1.07+/-0.12) resveratrol-treated VMC groups was significantly lower than that in the untreated VMC (2.33+/-0.18) and the low-dose resveratrol-treated VMC (2.17+/-0.19) groups (P<0.05). Compared with the untreated VMC group, serum concentrations of PICP and PIIINP in the high-dose and the middle-dose resveratrol-treated VMC groups were significantly reduced (P<0.05), while PINP concentrations increased significantly (P<0.05). CONCLUSIONS: Resveratrol can inhibit hyperplasia of myocardial collagen in the mouse model of chronic VMC, acting as an effective anti-fibrotic agent in the myocardium.

[The research of animal model setting-up in human intra-utero fetal cardiac intervention].

OBJECTIVE: To research the techniques and correlated issues during analogous procedure of human intro-utero fetal cardiac intervention in animal model, so as to impulse the clinical utilizing of cardiac intervention in human fetus with severe cardiovascular malformations. METHODS: Eight bigeminal pregnant ewes in latter 2nd-trimester and 3rd- trimester were taken into the research of fetal cardiac intervention. Under continuous ultrasound guidance, advanced an cannula and stylet needle through the maternal abdomen, uterine wall, and fetal lamb chest wall and into the fetal LV, then imitate human balloon aortic valvuloplasty at valve ring level. Probed into aspects of animal preparation, position of fetal lambs, paracentesis point selecting, main points of intervention, ultrasound utilizing, fetal lambs incubation and protection to placenta as well as umbilical cord. RESULTS: Eight pregnant ewes were all survival after procedure, 2 was executed after fetus' death, the other 6 continued gestation until spontaneous vaginal delivery after an uneventful pregnancy. After parturition the 6 ewes were in good condition. There were no nick infection, chorioamnionitis and other complications. Eight/sixteen fetal lambs were undergone intro-utero cardiac intervention. The values of body weight and Hct of lambs which were executed, pre-term and full-term delived were (1.77 +/- 0.14) kg vs. (2.15 +/- 0.23) kg vs. (2.41 +/- 0.19) kg and 29%o-33% vs. 27%-35% vs. 37%-41%. In autopsy, hydropericardium was found in 4/8 with 1-2.5 mL and 1/8 with 5 mL. Besides 1/8 with interventricular septum centesis injury, there was no centesis damage to endocardium, valve, chordae tendineae, papillary muscles and sortic tunics intima. Whereas there was no centesis injury to lung, liver and chylostomach, no trace of ericardium and thoracic infection. CONCLUSIONS: Animal model of intra-utero fetal cardiac intervention was setted up successfully, the experiences in this study was worth to be payed attention to in human fetal cardiac intervention.