A designer DNA tetrahedron-based molecular beacon for tumor-related microRNA fluorescence imaging in living cells.

The accurate and effective imaging of tumor-related miRNA in living cells has been playing an increasingly important role in cancer imaging. However, due to the low miRNA content and complex intracellular microenvironment, the current imaging methods of miRNAs in living cells still have some limitations. In this work, we developed a designer nanoprobe of tetrahedral DNA framework (TDF) combined with MB (termed TDFM nanoprobe) for the efficient fluorescence imaging of tumor-related miRNA-214 in living cells. In cell-free experiments, we demonstrated that the TDFM nanoprobe has sensitive detection and good specificity by fluorescence measurements. Before the TDFM nanoprobe was used for intracellular miRNA-214 fluorescence imaging, we confirmed its intracellular stability and negligible cytotoxicity by a standard MTT assay. In intracellular imaging experiments, we observed the strong fluorescence signal exhibited by the cells incubated with the TDFM nanoprobe using confocal fluorescence microscopy, which indicated that the TDFM nanoprobe was suitable for detecting and imaging tumor-related miRNA-214 in living cells. Furthermore, under the optimal incubation conditions, we employed the TDFM nanoprobe to study differences in the expression levels of tumor-related miRNA-214 in human breast cancer cells (MCF-7) and human umbilical vein endothelial cells (HUVEC). The TDFM nanoprobe we designed shows great potential to be applied in the development of DNA nanodevices, providing an improved strategy for the fluorescence imaging of miRNAs in living cells.

Poly-adenine-mediated spherical nucleic acid probes for live cell fluorescence imaging of tumor-related microRNAs.

BACKGROUND: Accurately detecting and quantifying tumor-related microRNAs (miRNAs) in living cells is of great value for early cancer diagnosis. Herein, we present poly-adenine (polyA)-mediated spherical nucleic acid (SNA) nanoprobes for intracellular miRNA imaging in living cells. METHODS AND RESULTS: polyA-mediated spherical nucleic acid (pASNA) nanoprobes consist of gold nanoparticles (AuNPs) anchored with fluorophore-labeled DNA molecules pre-hybridized with recognition sequences and polyA tails. The detection performance for miRNAs in vitro was studied to confirm the feasibility of pASNA nanoprobes for imaging live cell miRNAs. Before the pASNA nanoprobes were used for imaging intracellular miRNAs in MCF-7, HeLa, and LO2 cells, the stability and non-cytotoxicity were investigated using Dnase I and a standard colorimetric CCK8 assay. Flow cytometry, qRT-PCR analyses were conducted to confirm the different expression levels of miR-155 in live cells. Results showed that the pASNA nanoprobes had good detection sensitivity and specificity, excellent stability, and low toxicity. After incubating with pASNA nanoprobes, noticeable fluorescence signal enhancement could be clearly observed in MCF-7 and HeLa cells but not LO2 cells by confocal microscopy. Flow cytometry analysis and qRT-PCR indicated that MCF-7 and HeLa cells had higher miR-155 expression levels compared to LO2 cells. CONCLUSIONS: The pASNA nanoprobes we developed had good sensitivity and specificity, excellent nuclease stability and low toxicity, thus representing a new approach to exquisitely reveal the distribution of endogenous miRNAs in live cells.

Efficacy and Safety of Different Add Power Soft Contact Lenses on Myopia Progression in Children: A Systematic Review and Meta-Analysis.

BACKGROUND: In children, myopia has become a widespread and serious global public health problem. Soft multifocal contact lenses (SMCLs) have been widely studied to control myopia progression in children. However, their efficacy in myopia control in children and its adverse effects and which added power SMCLs are more effective and safer remains to be explored. OBJECTIVES: Evaluate the efficacy and safety of various add power SMCLs to slow myopia progression in children. METHOD: Eligible randomized controlled trials were retrieved from PubMed, MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials databases. The present meta-analysis analyzed the mean differences (MD) in myopic progression, axial length, and odds ratios for adverse effects and dropout rates between SMCLs with different added powers and control groups. Changes in visual performance were also systematically evaluated. RESULTS: Seven independent studies involving 805 children were included in the present meta-analysis. At 1-year, the weighted MD (WMD) in myopia progression between SMCL and control groups was -0.22 diopters (D) (95% confidence interval [CI]: -0.56 to 0.12 D) for low add power SMCLs, 0.09 D (95% CI: 0-0.19 D) for medium add power SMCLs, and 0.2 D (95% CI: 0.13, 0.27 D) for high add power SMCLs. At 2-years, the WMD for medium add power was 0.12 D (95% CI: -0.03 to 0.27 D), and for high add power was 0.25 D (95% CI: 0.14-0.35 D). No differences were detected for adverse effects (p = 0.2) and acceptability (p = 0.74) between different added powers. Additionally, differences in visual performance changes, produced by different added powers, were not detected. CONCLUSIONS: The present meta-analysis showed that high add power SMCLs are more effective and stable to control myopia progression. Besides, the adverse effects and acceptability were not related to the added power.

A double-tetrahedral DNA framework based electrochemical biosensor for ultrasensitive detection and release of circulating tumor cells.

Detecting circulating tumor cells (CTCs) in patients' blood is essential for early diagnosis, precise treatment and prognosis of cancer. Yet due to CTCs being extremely rare in the peripheral blood of patients, it is still a challenge to detect CTCs with high sensitivity and high selectivity. Here, we developed a double-tetrahedral DNA framework (DTDF) based electrochemical biosensor system (E-CTC sensor system) for ultrasensitive detection and release of CTCs. In this work, an upright tetrahedral DNA framework (UTDF) was used as a rigid scaffold to modify a screen-printed gold electrode (SPGE), and an inverted tetrahedral DNA framework (ITDF) provided three vertex chains to multivalently bind with aptamers. Meanwhile, a streptavidin tagged horseradish peroxidase homopolymer (SA-polyHRP) was linked to biotin-modified aptamers to significantly amplify the signal. Moreover, the captured CTCs could be effectively released via benzonase nuclease with little cell damage. Our E-CTC sensor system achieved a linear range from 1 to 105 MCF-7 cells with an ultralow detection limit of 1 cell. The release efficiency reached 88.1%-97.6% and the viability of the released cells reached up to 98%. We also detected the MCF-7 cells in mimic whole blood samples, suggesting that the E-CTC sensor system shows promise for use in clinical research.

Salt-effect enhanced hollow-fiber liquid-phase microextraction of glutathione in human saliva followed by miniaturized capillary electrophoresis with amperometric detection.

A hollow-fiber liquid-phase microextraction (HF-LPME) method was established for purification and enrichment of glutathione (GSH) in human saliva followed by a miniaturized capillary electrophoresis with amperometric detection system (mini-CE-AD). Based on regulating isoelectric point and increasing salt effect to modify donor phase, HF-LPME could provide high enrichment efficiency for GSH up to 471 times, and the extract was directly injected for mini-CE-AD analysis. The salt-effect enhanced HF-LPME/mini-CE-AD method has been successfully applied to saliva analysis, and acceptable LOD (0.46 ng/mL, S/N = 3) and recoveries (92.7-101.3%) could be obtained in saliva matrix. The sample pretreatment of this developed method was simple and required no derivatization, providing a potential alternative for non-invasive fluid analysis using portable instrument.

Synthesis of gadolinium-based Bi2S3 nanoparticles as cancer theranostics for dual-modality computed tomography/magnetic resonance imaging-guided photothermal therapy.

Development of a safe, efficient and inexpensive multifunctional nanoplatform using a facile approach for multimodal imaging and therapeutic functions becomes more and more practically relevant but challenging. In this work, we demonstrated a novel nanocomposites (Bi2S3-Gd) for computed tomography (CT)/magnetic resonance (MR) imaging-guided photothermal therapy (PTT) for cancer in vitro. It was achieved by modification of hydrophobic Bi2S3 with a smart amphiphilic gadolinium-chelated ligand. The as-prepared nanocomposites composed of low-cost Bi2S3 and gadolinium complexes, showed high stability, excellent biocompatibility and good photostability. It was observed that Bi2S3-Gd nanocomposites can efficiently convert the NIR light into heat, and then suppressed the growth of tumor cells under NIR laser irradiation. Apart from serving as an effective photothermal agent, the as-prepared nanomaterials could induce an efficient contrast enhancement for both CT and MR imaging at low concentrations of Bi and Gd, rendering more accurate diagnosis. This work suggests the potential of Bi2S3-Gd nanomaterials as a novel multifunctional nanoplatform for CT/MR imaging-guided PTT for cancer.

Correction: Fluorescence intensity coded DNA frameworks based on the FRET effect enable multiplexed miRNA imaging in living cells.

Correction for 'Fluorescence intensity coded DNA frameworks based on the FRET effect enable multiplexed miRNA imaging in living cells' by Xiaoshuang Zhao et al., Anal. Methods, 2023, 15, 3051-3056, https://doi.org/10.1039/D3AY00578J.

Encoding fluorescence intensity with tetrahedron DNA nanostructure based FRET effect for bio-detection.

Biocoding technology constructed by readable tags with distinct signatures is a brand-new bioanalysis method to realize multiplexed identification and bio-information decoding. In this study, a novel fluorescence intensity coding technology termed Tetra-FICT was reported based on tetrahedron DNA nanostructure (TDN) carrier and Forster Resonance Energy Transfer (FRET) effect. By modulating numbers and distances of Cy3 and Cy5 at four vertexes of TDN, different fluorescence intensities of twenty-six samples were produced at ∼565.0 nm (FICy3) and ∼665.0 nm (FICy5) by detecting fluorescence spectra. By developing an error correction mechanism, eleven codes were established based on divided intensity ranges of the final FICy3 together with FICy5 (Final-FICy3&FICy5). These resulting codes were used to construct barcode probes, with three miRNA biomarkers (miRNA-210, miRNA-199a and miRNA-21) as cases for multiplexed bio-assay. The high specificity and sensitivity were also demonstrated for the detection of miRNA-210. Overall, the proposed Tetra-FICT enriched the toolbox of fluorescence coding, which could be applied to multiplexing biomarkers detection.

Fluorescence intensity coded DNA frameworks based on the FRET effect enable multiplexed miRNA imaging in living cells.

miRNA analysis has played an important role in precise diagnosis, treatment and prognosis of cancer, especially multiplexed miRNA imaging. In this work, a novel fluorescence emission intensity (FEI) encoding strategy was developed based on a tetrahedron DNA framework (TDF) carrier and the FRET effect between Cy3 and Cy5. Six FEI-encoded TDF (FEI-TDF) samples were constructed by tuning the labeling number of Cy3 and Cy5 at the vertexes of the TDF. For fluorescence characterization in vitro, distinct FEIs in the spectra and different colors under ultraviolet (UV) irradiation of FEI-TDF samples were observed. By dividing the ranges of FEIs of samples, the stability of FEIs was highly improved. Based on the ranges of FEIs in each sample, five codes with good discrimination were finally developed. Before the application of intracellular imaging, the excellent biocompatibility of the TDF carrier was proved by CCK-8 assay. The barcode probes based on samples 12, 21 and 11 were designed as example models to realize multiplexed imaging of miRNA-16, miRNA-21 and miRNA-10b in MCF-7 cells with obviously different fluorescence merged colors. FEI-TDFs provide a new research perspective for the development of fluorescence multiplexing strategies in the future.

Using Network Pharmacology and Molecular Docking to Explore the Mechanism of Qiju Dihuang Pill against Dry Eye Disease.

Background: Dry eye disease (DED) is a multifactorial disease of the ocular surface, which affects the quality of life and work efficiency of affected patients. The traditional Chinese medicine formula Qiju Dihuang Pill (QJDHP) has a good therapeutic effect on DED. However, the pharmacological mechanism is not clear. Objective: To explore the mechanism of QJDHP in the treatment of DED based on network pharmacology. Method: The active components in QJDHP were screened in Traditional Chinese Medicine Systems Pharmacology (TCMSP), and putative molecular targets of QJDHP were identified using the SwissTargetPrediction database. DED-related targets were screened by GeneCards and OMIM. We established protein-protein interaction (PPI) and core targets and corresponding active compound network by Cytoscape to identify the core targets and main compounds of QJDHP against DED. DAVID database was utilized for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. Molecular docking was used to evaluate the binding activity between key active compounds and core targets. Results: The results of network pharmacology showed that 253 targets of QJDHP were related to DED. PPI network analysis showed the 18 core targets. The binding affinity of docking results ranged from -5.7 to -9.3 kcal/mol, indicating a good docking effect. The results of GO enrichment analysis showed that the mechanism of QJDHP in the treatment of DED mainly involved biological processes such as apoptosis, oxidative stress, response to estrogen, angiogenesis, and the regulation of transcription factors. KEGG analysis showed that QJDHP may be regulated by the TNF signaling pathway, Toll-like receptor signaling pathway, MAPK signaling pathway, and estrogen signaling pathway in the treatment of DED. Conclusion: In this study, we demonstrated the multicomponent, multitarget, and multichannel action mechanism of QJDHP in the treatment of DED and provided a foundation for further drug development research.

Creating accountable hospital service areas in China: a case analysis of health expenditure in the metropolis of Chengdu.

OBJECTIVES: To delineate hospital service areas (HSAs) using the Dartmouth approach in China and identify the hypothesised demand-side, supply-side and region-specific factors of health expenditure within HSAs. DESIGN: Population-based descriptive study. SETTING: We selected the metropolis of Chengdu, one of the three most populous cities in China as a case for the analysis, where approximately 16.33 million residents living. PARTICIPANTS: Individual-level in-patient discharge records (n=904 298) during the fourth quarter of 2018 (from 1 September to 31 December) were extracted from Sichuan Health Commission. Cases of non-residents of Chengdu were excluded from the datasets. METHODS: We conducted three sets of analyses: (1) apply Dartmouth approach to delineate HSAs; (2) use Geographic Information System (GIS)-based method to demonstrate health expenditure variations across delineated HSAs and (3) employ a three-level multilevel linear model to examine the association between health expenditure and demand-side, supply-side and region-specific factors. RESULTS: A total of 113 HSAs with a median population of 60 472 (ranging from 7022 to 827 750) was delineated. Total in-patient expenditure per admission varied more than threefold across HSAs after adjusting for age and gender. Apart from a list of demand-side factors, an increased number of physicians, healthcare facilities at higher levels and for-profit healthcare facilities were significantly associated with increased total in-patient expenditures. At the HSA level, the proportion of private healthcare facilities located in a single HSA was associated with increased total in-patient expenditure generated by that HSA, while the increased number of healthcare facilities in a HSA was negatively associated with the total in-patient expenditures. CONCLUSION: HSAs were delineated to help establish an accountable healthcare delivery system, which serves as local hospital markets to provide in-patient healthcare via connecting demanders with suppliers inside particular HSAs. Policy-makers should adopt HSAs to identify variations of total in-patient expenditures among different areas and the potential associated factors. Findings from the HSA-based analysis could inform the formulation of relevant health policies and the optimisation of healthcare resource allocations.

Diabetes-related avoidable hospitalisations and its relationship with primary healthcare resourcing in China: A cross-sectional study from Sichuan Province.

The reduction of diabetes-related avoidable hospitalisations (AHs) can be achieved via the provision of timely and effective primary healthcare (PHC), which has made diabetes AHs rate a widely adopted indicator for evaluating the performances of PHC systems. This study reported the AHs rate of diabetes and further explored its relationship with PHC resourcing in China. Hospital discharge data of the fourth quarters of 2016 and 2017 in Sichuan Province, China were used. The number of PHC doctors per 10,000 population and the proportion of PHC doctors on all doctors were used as indicators reflective of PHC resourcing. Linear regression models were used to explore the associations between PHC resourcing and AHs of diabetes. Age-standardised rates of diabetes-related AHs in Sichuan province, China were found to be 248.102 and 272.368 per 100,000 population in 2016 and 2017, respectively. A 10% increase in the number of PHC doctors per 10,000 population was associated with a reduction of 2.574 per 100,000 population in the age-standardised AHs rate of diabetes. In addition, 10% increase in the proportion of PHC doctors on all doctors was associated with a reduction of 10.839 diabetes-related AHs per 100,000 population. Based on subgroup analysis, PHC resourcing demonstrated to have a stronger impact on AHs of diabetes with long-term complications than on that of uncontrolled diabetes. Our findings reported that the diabetes AHs rates in Sichuan Province were prevalently high. We also found that increased PHC resourcing was associated with decreased diabetes-related AHs rates.

Tetrahedral DNA Framework-Programmed Electrochemical Biosenors with Gold Nanoparticles for Ultrasensitive Cell-Free DNA Detection.

Tumor-associated cell-free DNA (cfDNA) is a dynamic biomarker for genetic analysis, early diagnosis and clinical treatment of cancers. However, its detection has limitations because of its low abundance in blood or other complex bodily fluids. Herein, we developed an ultrasensitive cfDNA electrochemical biosensor (E-cfDNA sensor) based on tetrahedral DNA framework (TDF)-modified gold nanoparticles (Au NPs) with an interface for cfDNA detection. By accurately controlling the numbers of base pairs on each DNA framework, three types of TDFs were programmed: 26 base pairs of TDF; 17 base pairs of TDF; and 7 base pairs of TDF (TDF-26, TDF-16 and TDF-7, respectively). We also combined the TDF with hybridization chain reaction (HCR) to achieve signal amplification. Under optimal conditions, we detected the breast cancer susceptibility gene 1 (BRCA-1), a representative cfDNA closely related to breast cancer. An ultra-low detection limit of 1 aM with a linear range from 1 aM to 1 pM by TDF-26 was obtained, which was superior to the existing methods. Each type of TDF has excellent discrimination ability, which can distinguish single mismatch. More significantly, we also detected BRCA-1 in mimic serum samples, demonstrating that the E-cfDNA sensor has potential use in clinical research.

Tetrahedral DNA framework based CRISPR electrochemical biosensor for amplification-free miRNA detection.

microRNA (miRNA) is a kind of small non-coding RNA that has been regarded as potential biomarkers for cancers. Sensitive and specific detection of miRNA at low expression levels is highly desirable but remains challenging, especially for amplification-free and portable point of care (POC) diagnostics. The clustered regularly interspaced short palindromic repeats (CRISPR)/Cas13a has been recently discovered and used in the field of RNA detection. Nonetheless, most CRISPR/Cas13a-based methods were burdened with expensive equipment, time-consuming procedures, and complicated operations which were not suitable for POC analysis. In this work, we constructed a three-dimensional tetrahedral DNA framework based CRISPR-electrochemical biosensor (CRISPR-E). By combining tetrahedral DNA framework, CRISPR, and electrochemical biosensor, the process of activation, cleavage of Cas13a, and signal readout were all finished on the chip, and a simple, amplification-free and sensitive detection of miRNA-19b was realized. Under the optimal experimental conditions, a linear range from 10 pM to 104 pM with detection limit of 10 pM for miRNA-19b in buffer solution was achieved. Selectivity analysis indicated that our CRISPR-E had good distinguishing ability between miRNA-19b and miRNA-197. The results of miRNA-19b detection in mimic serum samples were consistent with that of the buffer solution. This all-on-chip strategy of our CRISPR-E is very suitable for POC testing.

Changes of Neolithic subsistence in south Hangzhou Bay coast, eastern China: An adaptive strategy to landscape processes.

The transition from hunting and gathering to agricultural subsistence is a striking feature of the Neolithic revolution worldwide. Known as the cradle of a series of representative Neolithic cultures, south Hangzhou Bay (SHB) witnessed substantial changes in both landscape and human subsistence during the Holocene, yet the relationship between them was not well established. Here, we combined archaeobotanical results from sediment cores with archaeological findings to illustrate the subsistence changes during the Neolithic regime in the context of the landscape process in SHB. Our result showed that SHB was inundated by marine transgression 8,200 years ago without significant human imprints. At 8,200-7,600 cal yr. BP, the initial coastal wetland formation at locations with the semi-enclosed landscape would have facilitated the activities of hunting-gathering, incipient rice cultivation, and collecting seafood if accessible. Pollen and phytoliths evidence from multiple sediment cores in the Yaojiang Valley (YJV) suggested a desalinization process of wetland in the following hundreds of years. This amelioration of the environment had favored the intermittent rice cultivation at various locations in the YJV, where archaeological evidence was absent. Since 7,000-6,600 cal yr. BP, as freshwater wetland expanded with coastal progradation, a wide variety of food resources became available. Meanwhile, rice domestication began to serve as a crucial food supplement as evidenced by both microfossil results and archaeological findings. With the expansion of the coastal plain after 5,500 cal yr. BP, rice farming became widespread and rice consumption was increasingly important in the diet, as supported by discoveries of upgraded farming tools, abundant rice remains, and ancient rice paddies. Above all, the change of subsistence from hunting-gathering to rice farming exhibited an adaptive strategy in response to landscape evolution from an initial marine-influenced setting to a later coastal plain.

Preparation and evaluation of chiral open-tubular columns supported with zeolite silica nanoparticles and single/dual chiral selectors using capillary electrochromatography with amperometric detection.

In this work, novel stationary phase coatings by zeolite SiO2NPs coupled with ß-cyclodextrin (ß-CD) or ß-CD/L-phenylalanine were developed for chiral open-tubular capillary electrochromatography (OT-CEC). The OT columns were prepared taking advantage of the strong adhesion of polydopamine in one-step method. Scanning electron micrography and electroosmotic flow were used to characterize the prepared single/dual-selector OT columns. Chiral separation of four chiral analytes (catechin/epicatechin, ephedrine/pseudoephedrine, ritodrine and salbutamol) was carried out in order to evaluate the performance of the prepared columns in OT-CEC with amperometric detection system. In terms of migration time, peak area, resolution, and selectivity factor of catechin/epicatechin and salbutamol, the run-to-run, day-to-day, and column-to-column repeatability were within 8.9%. Under the optimum conditions, the developed methods were applied for the analyses of Chinese herbal medicine Catechu herbs and salbutamol aerosol samples.

The effectiveness and safety of acupuncture for patients with myopia: A protocol for a systematic review and meta-analysis.

BACKGROUND: Myopia is a common visual disorder which has become a public health problem worldwide. Myopia and high myopia are substantial risk factors for severe visual impairment and other serious eye diseases. Acupuncture used to prevent and control myopia is a common practice in China, but it is controversial in other countries. This study aims to evaluate the efficacy and safety of acupuncture in delaying the progression of myopia in children and adolescents through systematic evaluation. METHODS AND ANALYSIS: The following electronic databases will be searched from inception to November 2019 regardless of publication status and language: Medline, EMBASE, Web of Science, the Cochrane Library, PubMed, China National Knowledge Infrastructure (CNKI), China Biology Medicine (CBM), Chinese Scientific Journal Database (VIP), Wanfang Database, Chinese Biomedical Literature Database (CBLD), Chinese Science and Technology Periodical Database (CSTPD). RCT registration websites, including http://www.ClinicalTrials.gov and http://www.chictr.org.cn, will also be searched. Review Manager V.5.3 will be used to analysis the statistic. Two reviewers (ZY and XW) will independently select studies, extract and code the data, assess risk of bias of the included studies, evaluate the quality of evidence for outcomes. RESULTS: This study will provide a rational synthesis of current evidences for acupuncture to delay the progression for myopia in children and adolescents. CONCLUSION: The conclusion of this study will provide evidence for evaluating the efficacy and safety of acupuncture to delay the progression for myopia in children and adolescents.

Simple preparation of photothermal nanomaterial GNR@SiO2 with enhanced drug loading content.

With the rising threat of cancers, gold nanorods (GNRs) based photothermal-chemotherapy is becoming an increasingly important strategy to cure cancers. There are some challenges faced by GNRs system including complicated synthesis process and low drug loading capacity. In this study, GNRs assisted mesoporous silica nanoparticles (GNR@SiO2 NPs) are fabricated by a simple method. The mesoporous SiO2 can not only prevent the aggregation of GNRs but also provide large hollow mesoporous structure to enhance drug loading capacity. Moreover, GNRs absorb near-infrared (NIR) light and convert it into heat. The temperature of the GNR@SiO2 solution was increased to ∼60 (2 W) and 90°C (3 W) after NIR radiation. The photothermal conversion efficiency was 32.60% of GNR@SiO2 under NIR light irradiation at 2 W, while 39.01% under NIR light irradiation at 3 W. The drug loading content of GNR@SiO2 was 22.3 ± 2.5%, which was higher than that of most reported GNR drug delivery systems. The authors also found that the GNR@SiO2@ doxorubicin may have a higher drug release rate under the conditions of the tumour microenvironment. The in vitro cytotoxity of GNR@SiO2 was demonstrated on HeLa cells. The experimental results indicate that GNR@SiO2 has great potential for synergistic treatment to kill cancer cells.

Superior adsorption performance of metal-organic-frameworks derived magnetic cobalt-embedded carbon microrods for triphenylmethane dyes.

In this work, magnetic Co/C microrods were successfully synthesized using direct carbonization of [Co3(BTC)2(H2O)12] precursors. After the carbonization, the original shape of the precursors was well-maintained, while the magnetic Co nanoparticles were well dispersed in the carbon matrix. The Co/C microrods were used as adsorbents for the adsorption of methyl blue (MB), acid fuchsin (AF), malachite green (MG), rhodamine B (Rh B), methyl orange (MO) and methylene blue (MTB) from their aqueous solutions. The results show that Co/C microrods can selectively adsorb triphenylmethane (TPM) dyes, while the adsorption capacities are about 13960, 11,610 and 4893 mg/g for MB, AF and MG dyes, respectively. The adsorption mechanism can be attributed to π-π interaction forces between the sp2 graphitic carbon in Co/C microrods and the triphenyl structure of dyes. In addition, the synthesized magnetic Co/C microrods can be easily removed from water using magnetic separation, and subsequently, regenerated using ethanol treatment.

Nickel nanoparticles encapsulated in porous carbon and carbon nanotube hybrids from bimetallic metal-organic-frameworks for highly efficient adsorption of dyes.

Nickel nanoparticles encapsulated in porous carbon/carbon nanotube hybrids (Ni/PC-CNT) were successfully prepared by a facile carbonization process using Ni/Zn-MOF as the precursor. Distinct from previous studies, Ni/Zn-MOF precursors were prepared via a direct precipitation method at room temperature for only 5min. After the carbonization, magnetic Ni nanoparticles were well embedded in the porous carbon and carbon nanotube. The obtained Ni/PC-CNT composites had a high surface area (999m2 g-1), large pore volume (0.86cm3 g-1) and well-developed graphitized wall. The Ni/PC-CNT composites showed excellent adsorption capacity for removal of malachite green (MG), congo red (CR), rhodamine B (Rh B), methylene blue (MB) and methyl orange (MO) from aqueous solution. The maximum adsorption capacity of Ni/PC-CNT composites were about 898, 818, 395, 312 and 271mg/g for MG, CR, RB, MB and MO dyes, respectively, which were much higher than most of the previously reported adsorbents. Moreover, the Ni/PC-CNT composites could be easily regenerated by washing it with ethanol and easy magnetic separation.