EPO promotes the progression of rheumatoid arthritis by inducing desialylation via increasing the expression of neuraminidase 3.

OBJECTIVE: Erythropoietin (EPO) known as an erythrocyte-stimulating factor is increased in patients with rheumatoid arthritis (RA). Nevertheless, the function of EPO in the process of RA and relative mechanism needs to be further clarified. METHODS: The level of EPO in serum and synovial fluid from patients with RA and healthy controls was determined by . Collagen-induced arthritis (CIA) mice were constructed to confirm the role of EPO on RA pathogenesis. Differentially expressed genes (DEGs) of EPO-treated fibroblast-like synoviocyte (FLS) were screened by transcriptome sequencing. The transcription factor of neuraminidase 3 (NEU3) of DEGs was verified by double luciferase reporting experiment, DNA pulldown, electrophoretic mobility shift assay and chromatin immunoprecipitation-quantitative PCR (qPCR) assay. RESULTS: The overexpression of EPO was confirmed in patients with RA, which was positively associated with Disease Activity Score 28-joint count. Additionally, EPO intervention could significantly aggravate the joint destruction in CIA models. The upregulation of NEU3 was screened and verified by transcriptome sequencing and qPCR in EPO-treated FLS, and signal transducer and activator of transcription 5 was screened and verified to be the specific transcription factor of NEU3. EPO upregulates NEU3 expression via activating the Janus kinase 2 (JAK2)-STAT5 signalling pathway through its receptor EPOR, thereby to promote the desialylation through enhancing the migration and invasion ability of FLS, which is verified by JAK2 inhibitor and NEU3 inhibitor. CONCLUSION: EPO, as a proinflammatory factor, accelerates the process of RA through transcriptional upregulation of the expression of NEU3 by JAK2/STAT5 pathway.

A fully human connective tissue growth factor blocking monoclonal antibody ameliorates experimental rheumatoid arthritis through inhibiting angiogenesis.

BACKGROUND: Connective tissue growth factor (CTGF) plays a pivotal role in the pathogenesis of rheumatoid arthritis (RA) by facilitating angiogenesis and is a promising therapeutic target for RA treatment. Herein, we generated a fully human CTGF blocking monoclonal antibody (mAb) through phage display technology. RESULTS: A single-chain fragment variable (scFv) with a high affinity to human CTGF was isolated through screening a fully human phage display library. We carried out affinity maturation to elevate its affinity for CTGF and reconstructed it into a full-length IgG1 format for further optimization. Surface plasmon resonance (SPR) data showed that full-length antibody IgG mut-B2 bound to CTGF with a dissociation constant (KD) as low as 0.782 nM. In the collagen-induced arthritis (CIA) mice, IgG mut-B2 alleviated arthritis and decreased the level of pro-inflammatory cytokines in a dose-dependent manner. Furthermore, we confirmed that the TSP-1 domain of CTGF is essential for the interaction. Additionally, the results of Transwell assays, tube formation experiments, and chorioallantoic membrane (CAM) assays showed that IgG mut-B2 could effectively inhibit angiogenesis. CONCLUSION: The fully human mAb that antagonizes CTGF could effectively alleviate arthritis in CIA mice, and its mechanism is tightly associated with the TSP-1 domain of CTGF.

Perfect Talbot self-imaging effect of aperiodic gratings.

We propose and investigate a class of aperiodic grating structure which can achieve perfect Talbot effect under certain conditions. The aperiodic grating structure is obtained by the superposition of two or more sine terms. In the case of two sine terms, the Talbot effect can be realized when the period ratio of two terms is arbitrary. While in the case of more than two sine terms, the period ratios of each term must meet certain extra conditions. The theory has been further verified by numerical simulations. It expands the field of Talbot effect and is of potential significance for subsequent research applications such as optical imaging and measurement.

Sarcopenia and mild kidney dysfunction and risk of all-cause and cause-specific mortality in older adults.

BACKGROUND: Sarcopenia has been identified as a risk factor for increased mortality in individuals with CKD. However, when considering individuals with mild kidney dysfunction prior to CKD, the impact of sarcopenia on adverse outcomes, particularly mortality, remains uncertain. METHODS: This study included 323 801 participants from the UK Biobank. Mild kidney dysfunction was defined as eGFR between 60 and 89.9 mL/min/1.73 m2, and sarcopenia was defined according to the criteria of the 2019 European Working Group of Sarcopenia in Older People. Cox proportional hazard models with inverse probability weighting and competing risk models were used for analysis. RESULTS: During a median follow-up of 11.8 years, 20 146 participants died from all causes. Compared with participants with normal kidney function and without sarcopenia, those with mild kidney dysfunction or sarcopenia had significantly increased risks of all-cause mortality [hazard ratio (HR): 1.16, 95% confidence interval (CI): 1.12 to 1.19; HR: 1.29, 95% CI: 1.20 to 1.37]; those with both mild kidney dysfunction and sarcopenia had an even higher risk of all-cause mortality (HR: 1.61, 95% CI: 1.52 to 1.71), with a significant overall additive interaction (relative risk due to interaction 0.17, 95% CI: 0.05 to 0.29). Further subgroup analyses revealed that the associations of probable sarcopenia with all-cause and cause-specific mortality (non-accidental cause, non-communicable diseases, and cancer) were stronger among participants with mild kidney dysfunction than those with normal kidney function. CONCLUSIONS: The study indicates that sarcopenia and mild kidney dysfunction synergistically increase the risk of all-cause and cause-specific mortality. Early recognition and improvement of mild kidney function or sarcopenia in older people may reduce mortality risk but would require more prospective confirmation.

Analysis of virulence and immunogenic factors in Aeromonas hydrophila: Towards the development of live vaccines.

Aeromonas hydrophila, a bacterium that is widespread in aquatic environments, is responsible for causing haemorrhagic disease in both aquatic and terrestrial species. With the purpose of developing a live vaccine, herein we have investigated nine strains of A. hydrophila (Ah-01 to Ah-09) isolated from diseased fish. A study of virulence factors that contribute to pathogenicity and immunogenicity in the host Cyprinus carpio suggests that the presence of ß-hly, act and fla genes contribute to pathogenesis: strains Ah-01, Ah-02 and Ah-03 (ß-hly+ /act+ /fla+ genotype) were highly pathogenic to C. carpio, whereas Ah-05 and Ah-06 (ß-hly- /act- /fla- genotype) showed weak pathogenicity. Accordingly, Ah-02 and Ah-03 were selected to prepare inactivated vaccines, whereas Ah-05 and Ah-06 were chosen as live vaccines. Ah-06 live vaccine was found to have the best protective efficacy, with a protective rate of about 85%, whereas rates of other vaccines were significantly lower, in the range 37%-59%. In addition, DNA vaccines based on genes altA, aha and omp showed immune protection rates of 25%, 37.5% and 75%, respectively. Our data demonstrate that the ß-hly- /act- /fla- /altA+ /aha+ /omp+ genotype has weak pathogenicity and high immunogenicity, and provide a simple and effective way to screen for live A. hydrophila vaccines.

Blocking OLFM4/HIF-1α axis alleviates hypoxia-induced invasion, epithelial-mesenchymal transition, and chemotherapy resistance in non-small-cell lung cancer.

Hypoxia is a common biological hallmark of solid cancers, which has been proposed to be associated with oncogenesis and chemotherapy resistance. The purpose of the present study was to investigate the role and underlying mechanisms of olfactomedin 4 (OLFM4) in the hypoxia-induced invasion, epithelial-mesenchymal transition (EMT), and chemotherapy resistance of non-small-cell lung cancer (NSCLC). We observed dramatically upregulated expression of OLFM4 in several NSCLC cell lines, and this effect was more pronounced in A549 and H1299 cells. In addition, our data revealed that OLFM4 expression was remarkably increased in both A549 and H1299 cells under hypoxic microenvironment, accompanied by enhanced levels of hypoxia-inducible factor (HIF)-1α protein. The HIF-1α level was elevated in response to hypoxia, resulting in the regulation of OLFM4. Interestingly, OLFM4 was a positive regulator of hypoxia-driven HIF-1α production. Moreover, depletion of OLFM4 modulated multiple EMT-associated proteins, as evidenced by the enhanced E-cadherin levels along with the diminished expression of N-cadherin and vimentin in response to hypoxia, and thus blocked invasion ability of A549 and H1299 cells following exposure to hypoxia. Furthermore, ablation of OLFM4 accelerated the sensitivity of A549 cells to cisplatin under hypoxic conditions, implying that OLFM4 serves as a key regulator in chemotherapeutic resistance under hypoxia. In conclusion, OLFM4/HIF-1α axis might be a potential therapeutic strategy for NSCLC.

[Intestinal absorption properties of ponicidin by single pass perfusion model in rats].

To determine the absorption properties and study the intestinal absorption kinetics of poncidin in rats. In situ single pass perfusion model was combined with High Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS/MS) method to investigate the intestinal absorption characteristics and calculate absorption parameters with aspects of drug absorption, concentration and perfusion medium. The absorption of poncidin under acid condition at pH 6.5 was more stable, where intestinal enzymes showed little influence on metabolism, and the absorption was significantly higher than that in pH alkaline condition at pH 8.0 (P<0.05). Drug concentrations had no significant influence on absorption rate constant of the same intestinal segment Ka and apparent permeability coefficient Papp values of poncidin. Different concentrations of poncidin showed no significant differences in the Ka and Papp values among duodenum, jejunum and colon, but the values were significantly lower than ileum absorption parameters, with significant differences (P<0.05). There was no significant effect of verapamil on intestinal absorption of poncidin. The results showed that poncidin could be absorbed at all the studied intestinal segments while ileum seemed to be the best absorption segment in the concentration range of 10-1 000 µg·L⁻¹. The absorption was characterized by a linear dynamic process of passive transport, without absorption saturation. Weak acid environment was helpful for the intestinal absorption of poncidin, and ponicidin was not a substrate of P-glycoprotein (P-gp).

[Interaction and mechanism between poinicidin and BSA].

To establish a sensitive and specific LC-MS/MS method for determination of the binding conditions of ponicidin with bovine serum albumin (BSA) and analysis of its mechanism. The protein binding rates and related binding constants of ponicidin in BSA samples were determined by ultrafiltration and LC-MS/MS. Scatchard equation was used to calculate the binding constant (Ka) of ponicidin in BSA samples as well as the number of binding sites (n), and the mechanism on ponicidin binding with BSA was explored. The results showed that the average protein binding rate of ponicidin with BSA was 57.2%, mainly as grade Ⅰ intensive binding, and the relevant binding constant was 2.54×104 L•µg⁻¹, with a binding site number of n=0.75. The binding of ponicidin with BSA had no concentration dependence within the investigated concentrations. The established method in this study showed high sensitivity, specificity, simple operation and met the analysis requirements, and the calculation of binding constant laid foundation for the clinical drug interactions and pharmacokinetics research.

[A Study on Quantitative Evaluation of Damage in Conservation of Ceramics from Huaguangjiao I Shipwreck with ICP-AES].

ICP-AES was used to determine the elemental composition of solutions in different conservation steps for understanding the impact of cleaning agents on ceramics from Huaguangjiao I shipwreck. The results showed that high content in solution of Al, Fe, Mg ions, which can be indexes to reflect the damage in conservation of ceramics. According to these indexes, we discovered that agents of strong cleaning ability bring more damage to ceramic samples. Meanwhile, the state of preservation of the ceramics was closely related to the damage in conservation. Ceramics in an excellent state of preservation endure less damage than that in bad state. We also found that each cleaning agent cause certain degree of damage on porcelains, even neutral reagent, like deionized water. Moreover, moderate cleaning reagent, when using a long time, bring the same degree of damage as the strong acid. Therefore, in actual protection procedure, for conservation ceramics safe and effective, damage of each cleaning agents and cumulative damage should be considered.

[Study on Provenance of Kraak Porcelains from "Nan'ao I" Shipwreck].

The "Kraak Porcelain" was a kind of Blue and White Porcelain which exported from China to Europe in Ming and Qing period. The study of Kraak Porcelain is a focus issue in international field of porcelain research. In 2007, the discovery of "Nan'ao I" Shipwreck of Ming Dynasty and the porcelains loaded in it, provided precious materials for the research on Kraak Porcelain. In this paper, we explored the provenance of 10 Kraak Porcelain samples from Nan'ao I, using both traditional visual method and WDXRF.

[Analysis of volatile compounds of fresh tea leaves from yaoluoping nature preserve by SDE-GC-MS].

OBJECTIVE: To study the volatile compounds of fresh tea leaves from Yaoluoping Nature Preserve, and to provide scientific basis for the quality and medicinal value of tea from high mountainous area. METHODS: The volatile compounds were extracted from fresh tea leaves by simultaneous distillation and extraction, and analyzed by gas chromatography-mass spectrum (GC-MS). RESULTS: 41 volatile compounds were identified from two tea cultivars, Shifoxiang and Shifocui. Shifoxiang had 32 kinds of volatile compounds and Shifocui had 38 kinds of volatile compounds. The main volatile components of Shifoxiang and Shifocui were green leaf volatiles. The kind and relative content of terpenes of Shifocui were more than that of Shifoxiang. Also the kind and relative content of ketones of Shifocui were more than that of Shifoxiang. There was one kind of heterocyclic compound of Shifocui. CONCLUSION: The main volatile components of Shifoxiang and Shifocui had an important role for the formation of unique aroma of high mountain ous tea. The composition and proportion of volatile components between Shifoxiang and Shifocui had certain differences. Some trace components may be associated with defense in the process of tea plant growth. The functional components from the volatile components had good medicinal value, worthy of further research.

Interactive effects of physical activity and sarcopenia on incident ischemic heart disease: Results from a nation-wide cohort study.

BACKGROUND AND AIMS: Lack of physical activity (PA) and sarcopenia is a known risk factors for ischemic heart disease (IHD). However, considering their coexistence in the middle-aged and elderly population, the interaction of these two factors remains uncertain. Here, we investigated the interactive effects of PA and sarcopenia on IHD. METHODS: We extracted 344,688 participants free of IHD at baseline from the UK Biobank. PA was classified into low, moderate, and high according to the International Physical Activity Questionnaire. Sarcopenia was identified in accordance with the European Working Group on Sarcopenia in Older People 2. Cox proportional hazard models were applied to estimate the effect of PA and sarcopenia on incident IHD and its subtypes. We also used objective PA data measured by wrist-worn devices to repeat these analyses. RESULTS: Over a median follow-up of 11.7 years, 24,809 (7.2%) participants developed incident IHD. Lack of PA was associated with a higher risk of IHD after adjusting for potential confounders. The hazard ratio (HR) was 1.09 (95% CI: 1.05-1.13) for individuals without sarcopenia and 1.29 (95% CI: 1.17-1.42) for those with sarcopenia. Regarding the joint effect, the combination of low PA and sarcopenia was associated with the highest risk of IHD, with an HR of 1.54 (95% CI: 1.44-1.66), and both additive and multiplicative interactions were significant (RERI 0.27, 95% CI: 0.14-0.39, p-interaction <0.01). For subtypes of IHD, the interaction was pronounced in acute myocardial infarction and chronic ischemic heart disease. CONCLUSIONS: These results suggest a synergistic interaction between lack of PA and sarcopenia on the risk of IHD. Findings from this study may help facilitate more effective primary prevention of IHD.

Alizarin complexone modified UiO-66-NH2 as dual-mode colorimetric and fluorescence pH sensor for monitoring perishable food freshness.

Food prone to spoilage has a huge food safety hazard, threatening people's health, so early detection of food spoilage is a continuous and urgent need. Herein, we developed a dual-mode response sensor, alizarin complexone@UiO-66-NH2, which can accurately detect pH. The sensor demonstrated significant changes in color from pale yellow to deep pink, while the fluorescence shifted from light blue to blue violet. Moreover, both UV absorption and fluorescence intensity showed a linear correlation with pH raging from 4.5 to 7.5. These results indicate that the sensor effectively responds to pH, making it suitable for detecting the freshness of perishable food. To put this into practice, we integrated the sensor with cellulose-based filter paper to determine the freshness of shrimp and beef, which was proved to be effective in assessing freshness. In the future, it can be combined with intelligent colorimetric and fluorescence instruments to achieve visual detection.

Recognition and detection of histamine in foods using aptamer modified fluorescence polymer dots sensors.

Histamine has been known as a momentous cause of biogenic amine poisoning. Therefore, the content of histamine in foods is strictly required to be controlled within a certain range. Here, an aptamer fluorescent sensor was developed for detection of histamine. Poly [(9, 9-di-n-octylfluorenyl-2, 7-diyl)-alt-(benzo [2,1,3] thiadia-zol-4, 8-diyl)] (PF8BT) and the styrene maleic anhydride copolymer (PSMA) were used for the preparation of PF8BT-Polymer dots (PF8BT-Pdots). PF8BT-Pdots and the cyanine3-phosphoramidite (Cy3) were linked through aptamer to achieve the ratiometric detection for histamine. PF8BT-Pdots were partly quenched by Cy3 due to the fluorescence resonance energy transfer (FRET), when the histamine molecule was recognized by aptamer on the surface of PF8BT-Pdots. A linear range (3-21 µmol/L) was obtained for histamine detection with a low limit of detection (LOD = 0.38 µmol/L). PF8BT aptamer Pdots (PF8BT-A) were used to detect histamine in simply treated aquaculture water and tuna. The cell imaging of HeLa cells presented a good biosecurity and outstanding fluorescent imaging capability of PF8BT-A. The aptamer fluorescent sensors provided a new platform for rapid and accurate detection of histamine in aquatic products and had great potential for the application in food safety and quality control.

Ambient fine particulate matter chemical composition associated with in-hospital case fatality, hospital expenses, and length of hospital stay among patients with heart failure in China.

*Joint senior authorship. BACKGROUND: Previous studies have observed the adverse effects of ambient fine particulate matter pollution (PM2.5) on heart failure (HF). However, evidence regarding the impacts of specific PM2.5 components remains scarce. METHODS: We included 58 129 patients hospitalised for HF between 2013 and 2017 in 11 cities of Shanxi, China from inpatient discharge database. We evaluated exposure to PM2.5 and its components ((sulphate (SO42-), nitrate (NO3-), ammonium (NH4+), organic matter (OM) and black carbon (BC)), along with meteorological factors using bilinear interpolation at each patients' residential address. We used multivariable logistic and linear regression models to assess the associations of these components with in-hospital case fatality, hospital expenses, and length of hospital stay. RESULTS: Increase equivalents to the interquartile range (IQR) in OM (odds ratio (OR) = 1.13; 95% confidence interval (CI) = 1.02, 1.26) and BC (OR = 1.14; 95% CI = 1.02, 1.26) were linked to in-hospital case fatality. Per IQR increments in PM2.5, SO42-, NO3-, OM, and BC were associated with cost increases of 420.62 (95% CI = 285.75, 555.49), 221.83 (95% CI = 96.95, 346.71), 214.93 (95% CI = 68.66, 361.21), 300.06 (95% CI = 176.96, 423.16), and 303.09 (95% CI = 180.76, 425.42) CNY. Increases of 1 IQR in PM2.5, SO42-, OM, and BC were associated with increases in length of hospital stay of 0.10 (95% CI = 0.02, 0.19), 0.09 (95% CI = 0.02, 0.17), 0.10 (95% CI = 0.03, 0.17), and 0.16 (95% CI = 0.08, 0.23) days. CONCLUSIONS: Our findings suggest that ambient SO42-, OM, and BC might be significant risk factors for HF, emphasising the importance of formulating customised guidelines for the chemical constituents of PM and controlling the emissions of the most dangerous components.

Air pollution, APOE genotype and risk of dementia among individuals with cardiovascular diseases: A population-based longitudinal study.

Individuals with cardiovascular disease (CVD) are particularly vulnerable to dementia, but it remains unclear whether air pollution exposure links with higher risk of dementia among those with CVD. The data were derived from the UK Biobank study (UKB). Dementia-free participants with CVD at baseline were included. Air pollution exposure was assessed through land use regression models, including particulate matter (PM2.5, PM2.5-10, and PM10), nitrogen dioxide (NO2), and nitrogen oxides (NOX). A Cox proportional hazards model was used to investigate the associations between air pollution exposure and incident dementia among individuals with CVD. Air pollution was associated with dementia among individuals with CVD, and the hazard ratios of dementia associated with each interquartile range (IQR) µg/m3 increase in air pollution were 1.07 (95% CI: 1.02, 1.12) for PM2.5, 1.10 (95% CI: 1.04, 1.15) for PM10, 1.08 (95% CI: 1.03, 1.14) for NO2 and 1.05 (95% CI: 1.00, 1.09) for NOx. Associations between air pollution and all-cause dementia were found to be significant among individuals with hypertension. Adverse effects of air pollution were also observed for Alzheimer's dementia (AD) and vascular dementia (VaD), with a higher effect for AD. Observed associations remained similar in subgroups of APOE ε4 carriers and noncarriers, although there was a higher risk difference across different air pollution concentration among these individuals carrying APOE ε4. Air pollution emerges as a critical risk factor for dementia among individuals with CVD, regardless of genetic susceptibility indicated by the APOE genotype. Notably, individuals with hypertension might be susceptible to the adverse effects of air pollution, leading to a higher incidence of dementia. Understanding these impacts on dementia among individuals with CVD may promote better targeted prevention and clinical management strategies.

Xiaoqinglong decoction mitigates nasal inflammation and modulates gut microbiota in allergic rhinitis mice.

Introduction: Allergic rhinitis (AR) is a respiratory immune system disorder characterized by dysregulation of immune responses. Within the context of AR, gut microbiota and its metabolites have been identified as contributors to immune modulation. These microorganisms intricately connect the respiratory and gut immune systems, forming what is commonly referred to as the gut-lung axis. Xiaoqinglong Decoction (XQLD), a traditional Chinese herbal remedy, is widely utilized in traditional Chinese medicine for the clinical treatment of AR. In this study, it is hypothesized that the restoration of symbiotic microbiota balance within the gut-lung axis plays a pivotal role in supporting the superior long-term efficacy of XQLD in AR therapy. Therefore, the primary objective of this research is to investigate the impact of XQLD on the composition and functionality of the gut microbiota in a murine model of AR. Methods: An ovalbumin-sensitized mouse model to simulate AR was utilized, the improvement of AR symptoms after medication was investigated, and high-throughput sequencing was employed to analyze the gut microbiota composition. Results: XQLD exhibited substantial therapeutic effects in AR mice, notably characterized by a significant reduction in allergic inflammatory responses, considerable alleviation of nasal symptoms, and the restoration of normal nasal function. Additionally, following XQLD treatment, the disrupted gut microbiota in AR mice displayed a tendency toward restoration, showing significant differences compared to the Western medicine (loratadine) group. Discussion: This results revealed that XQLD may enhance AR allergic inflammatory responses through the regulation of intestinal microbiota dysbiosis in mice, thus influencing the dynamics of the gut-lung axis. The proposal of this mechanism provides a foundation for future research in this area.

Initial Upper Palaeolithic material culture by 45,000 years ago at Shiyu in northern China.

The geographic expansion of Homo sapiens populations into southeastern Europe occurred by ∼47,000 years ago (∼47 ka), marked by Initial Upper Palaeolithic (IUP) technology. H. sapiens was present in western Siberia by ∼45 ka, and IUP industries indicate early entries by ∼50 ka in the Russian Altai and 46-45 ka in northern Mongolia. H. sapiens was in northeastern Asia by ∼40 ka, with a single IUP site in China dating to 43-41 ka. Here we describe an IUP assemblage from Shiyu in northern China, dating to ∼45 ka. Shiyu contains a stone tool assemblage produced by Levallois and Volumetric Blade Reduction methods, the long-distance transfer of obsidian from sources in China and the Russian Far East (800-1,000 km away), increased hunting skills denoted by the selective culling of adult equids and the recovery of tanged and hafted projectile points with evidence of impact fractures, and the presence of a worked bone tool and a shaped graphite disc. Shiyu exhibits a set of advanced cultural behaviours, and together with the recovery of a now-lost human cranial bone, the record supports an expansion of H. sapiens into eastern Asia by about 45 ka.

Construction of a nanoscale metal-organic framework aptasensor for fluorescence ratiometric sensing of AFB1 in real samples.

Aflatoxins B1 (AFB1) that could contaminate agricultural products has received sustained attention due to its high toxicity and wide distribution. Therefore, sensitive and facile detection method for AFB1 is significant for food safety and control. In this work, a ratiometric fluorescence NMOFs-Aptasensor was developed based on the combination of Cy3-modified aptamer and zirconium-based nanoscale metal-organic frameworks (NMOFs). NMOFs served as energy donors, and Cy3 labeled on the AFB1 aptamer was used as an acceptor. An energy donor-acceptor pair was fabricated in the NMOFs-Aptasensor. With AFB1 selectively caught by the AFB1 aptamer, the fluorescence of the NMOFs-Aptasensor changed via fluorescence resonance energy transfer (FRET), and the fluorescence spectra changed accordingly. The ratiometric fluorescence signal was utilized to quantitatively measure AFB1. The reported NMOFs-Aptasensor presented great detection performance from 0 to 3.33 ng mL-1, with an LOD of 0.08 ng mL-1. Moreover, the fluorescence sensor was successfully applied to detect AFB1 in real samples.

Nanoscale semiconducting polymer dots with rhodamine spirolactam as fluorescent sensor for mercury ions in living systems.

Mercury ion (Hg2+), as one of the most poisonous heavy metal ions, could seriously damage mental and neurological functions thus causing severe diseases. A fluorescent ratiometric sensor based on semiconducting polymer dots (Pdots) and rhodamine spirolactam derivate was developed for the detection of Hg2+. The Pdots were prepared by Poly [(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-diphenylene-vinylene-2-methoxy-5-{2-ethylhexyloxy}-benzene)] (PDDB) with emitting strong green fluorescence. The organic fluorescence dye N-(rhodamine-B) lactam-hydrazine (RhBH), as Hg2+-recognizing monomer, was conjugated to the surface of Pdots. Hg2+ could specifically trigger ring-opening process of RhBH and thus induce strong Förster resonance energy transfer (FRET) effect, resulting in the green fluorescence decrease of Pdots (energy donor) and red emission derived from the ring-opened RhBH (energy acceptor) increasing. PDDB@RhBH showed a sensitive and reversible response toward Hg2+ and had a great performance on resisting interferences from various biological analytes. Additionally, both fluorescent imaging in living cells and zebrafish, and systemic toxicity analysis in rats demonstrated that PDDB@RhBH was a great potential fluorescent sensor for quantitative Hg2+ imaging in living systems.