Topochemical synthesis of 2D materials Xiao, Xu; Wang, Hao; Urbankowski, Patrick ...
Chemical Society reviews,
11/2018, Volume:
47, Issue:
23
Journal Article
Peer reviewed
Since the demonstration of the unique properties of single-layer graphene and transition metal dichalcogenides (TMDs), research on two-dimensional (2D) materials has become one of the hottest topics, ...with the family of 2D materials quickly expanding. This expansion is mainly attributable to the development of new synthesis methods to create new materials. This review will summarize and critically analyze topochemical synthesis methods for synthesizing novel 2D materials. For example, the emerging family of 2D transition metal carbides, nitrides and carbonitrides (MXenes) are synthesized primarily by selective etching of "A" (metal) elements from MAX phases. Another 2D material, hydrogenated germanene is produced by selective etching of calcium digermanide (CaGe
2
). The topochemical transformation of one dichalcogenide into another and 2D oxides into 2D carbides or nitrides have attracted great attention because materials with many useful and diverse properties can be obtained by these methods. Topochemical synthesis methods provide alternative ways of synthesizing 2D materials not requiring van der Waals bonded solid precursors or vapor phase deposition, but they have not been comprehensively reviewed. In this review, we describe common principles of topochemical synthesis of 2D materials, explain synthesis mechanisms and offer an outlook for future research.
This review summarizes the rapidly-developed topochemical synthesis of 2D materials, explains the growth mechanisms and provides outlooks for future research.
A layerlike MOF (MIL-124, orGa2(OH)4(C9O6H4)) has been prepared and chosen as a parent compound to encapsulate Eu3+ cations by one uncoordinated carbonyl group in its pores. The Eu3+-incorporated ...sample (Eu3+@MIL-124) is fully characterized, which shows excellent luminescence and good fluorescence stability in water or other organic solvents. Subsequently, we choose Eu3+@MIL-124 as sensitive probe for sensing metal ions, anions, and organic small molecules because of its robust framework. Studying of the luminescence properties reveals that the complex Eu3+@MIL-124 was developed as a highly selective and sensitive probe for detection of Fe3+ (detection limit, 0.28 μM) and Fe2+ ions through fluorescence quenching of Eu3+ and MOF over other metal ions. In connection to this, a probable sensing mechanism was also discussed in this paper. In addition, when Eu3+@MIL-124 was immersed in the different anions solutions and organic solvents, it also shows highly selective for Cr2O7 2–(detection limit, 0.15 μM)and acetone. Remarkably, it is the first Eu-doped MOF to exhibit an excellent ability for the detection of Fe3+ and Fe2+ in an aqueous environment without any structural disintegration of the framework.
AbstractObjectiveTo study the clinical characteristics of patients in Zhejiang province, China, infected with the 2019 severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) responsible for ...coronavirus disease 2019 (covid-2019).DesignRetrospective case series.SettingSeven hospitals in Zhejiang province, China.Participants62 patients admitted to hospital with laboratory confirmed SARS-Cov-2 infection. Data were collected from 10 January 2020 to 26 January 2020.Main outcome measuresClinical data, collected using a standardised case report form, such as temperature, history of exposure, incubation period. If information was not clear, the working group in Hangzhou contacted the doctor responsible for treating the patient for clarification.ResultsOf the 62 patients studied (median age 41 years), only one was admitted to an intensive care unit, and no patients died during the study. According to research, none of the infected patients in Zhejiang province were ever exposed to the Huanan seafood market, the original source of the virus; all studied cases were infected by human to human transmission. The most common symptoms at onset of illness were fever in 48 (77%) patients, cough in 50 (81%), expectoration in 35 (56%), headache in 21 (34%), myalgia or fatigue in 32 (52%), diarrhoea in 3 (8%), and haemoptysis in 2 (3%). Only two patients (3%) developed shortness of breath on admission. The median time from exposure to onset of illness was 4 days (interquartile range 3-5 days), and from onset of symptoms to first hospital admission was 2 (1-4) days.ConclusionAs of early February 2020, compared with patients initially infected with SARS-Cov-2 in Wuhan, the symptoms of patients in Zhejiang province are relatively mild.
Quinoline and quinazoline alkaloids, two important classes of N‐based heterocyclic compounds, have attracted tremendous attention from researchers worldwide since the 19th century. Over the past 200 ...years, many compounds from these two classes were isolated from natural sources, and most of them and their modified analogs possess significant bioactivities. Quinine and camptothecin are two of the most famous and important quinoline alkaloids, and their discoveries opened new areas in antimalarial and anticancer drug development, respectively. In this review, we survey the literature on bioactive alkaloids from these two classes and highlight research achievements prior to the year 2008 (Part I). Over 200 molecules with a broad range of bioactivities, including antitumor, antimalarial, antibacterial and antifungal, antiparasitic and insecticidal, antiviral, antiplatelet, anti‐inflammatory, herbicidal, antioxidant and other activities, were reviewed. This survey should provide new clues or possibilities for the discovery of new and better drugs from the original naturally occurring quinoline and quinazoline alkaloids.
By taking advantage of facile preparation and sensitive recognition capacity, the first example of a fluorescence system based on Eu(III) functionalized UiO(bpdc) (UMOFs) has been constructed for ...effective combination of ions recognition and logic computing. All the ions, including Hg2+, Ag+, and S2− in the system are water harmful, which can be recognized through affecting energy transfer or framework structure. By the self‐assembling, competing and connecting with each other, Eu(III)@UMOFs and the ions have achieved the implementation of Boolean logic network system connecting the elementary logic operations (NOR, INH, and IMP) and integrative logic operation (OR + INH), also obtaining computing keypad‐lock security system by sequential logic operation. To deal with uncertain information in the analog region of nonlinear response (fluorescence and concentration), soft computation through the formulation of fuzzy logic operation has been constructed. On the basis of Boolean logic and fuzzy logic, one intelligent molecular searcher can be realized by taking chemical events (Hg2+, Ag+, and S2−) as programmable words and chemical interactions as syntax. Considering the particularity of all the input ions, the approach is helpful in developing the advanced logic program based on Eu(III)@UMOFs for application in environmental monitoring.
By combining ion recognition and logic computing (Boolean and fuzzy), an intelligent molecular searcher for polluting ions (Hg2+, Ag+, and S2−) in water has been constructed based on fluorescence Eu(III) functionalized UiO(bpdc) system and the molecular searcher is helpful in developing the advanced logic program for application in environmental monitoring.
Reactive oxygen species (ROS) depletion and low ROS production that result from the intratumoral redox metabolism equilibrium and low energy conversion efficiency from ultrasound mechanical energy to ...ROS‐represented chemical energy, respectively, are two vital inhibitory factors of sonodynamic therapy (SDT). To address the two concerns, a tumor metabolism‐engineered composite nanoplatform capable of intervening intratumoral ROS metabolism, breaking the redox equilibrium, and reshaping the tumor microenvironment is constructed to reinforce SDT against tumors. In this metabolism‐engineered nanoplatform, Nb2C nanosheets serve as the scaffold to accommodate TiO2 sonosensitizers and l‐buthionine‐sulfoximine. Systematic experiments show that such nanoplatforms can reduce ROS depletion via suppressing glutathione synthesis and simultaneously improving ROS production via the Nb2C‐enhanced production and separation of electron–hole pairs. Contributed by the combined effect, net ROS content can be significantly elevated, which results in the highly efficient anti‐tumor outcomes in vivo and in vitro. Moreover, the combined design principles, that is, tumor metabolism modulation for reducing ROS depletion and electron–hole pair separation for facilitating ROS production, can be extended to other ROS‐dependent therapeutic systems.
An intratumoral metabolism modulation‐engineered sonodynamic therapy (SDT)‐based nanoplatform has been constructed to break the reactive oxygen species (ROS)‐involved redox metabolism equilibrium and reshape the tumor microenvironment for reducing ROS depletion, and simultaneously facilitate ROS production via enhancing the production and separation of electron–hole pairs, which enables the significantly improved net content of ROS for highly‐efficient SDT against tumors.
Unsafe food is a huge threat to human health and the economy, and detecting food spoilage early is an ongoing and imperative need. Herein, a simple and effective strategy combining a fluorescence ...sensor and one‐to‐two logic operation is designed for monitoring biogenic amines, indicators of food spoilage. Sensors (methyl red@lanthanide metal–organic frameworks (MR@EuMOFs)) are created by covalently modifying MR into NH2‐rich EuMOFs, which have a high quantum yield (48%). A double‐stimuli‐responsive fluorescence center is produced via energy transfer from the ligands to Eu3+ and MR. Portable sensory hydrogels are obtained by dispersing and solidifying MR@EuMOFs in water‐phase sodium salt of carboxy methyl cellulose (CMC‐Na). The hydrogels exhibit a color transition upon “smelling” histamine (HI) vapor. This transition and shift in the MR‐based emission peak are closely related to the HI concentration. Using the HI concentration as the input signal and the two fluorescence emissions as output signals, an advanced analytical device based on a one‐to‐two logic gate is constructed. The four output combinations, NOT (0, 1), YES (1, 0), PASS 1 (1, 1), and PASS 0 (0, 0), allow the direct analysis of HI levels, which can be used for real‐time food‐freshness evaluation. The novel strategy suggested here may be a new application for a molecular logic system in the sensing field.
By covalently modifying COOH‐rich methyl red (MR) to NH2‐rich lanthanide metal–organic frameworks, a double‐stimuli‐responsive fluorescent sensor for detection of biogenic amines is fabricated and an advanced analytical device based on a one‐to‐two logic gate is constructed for application in real‐time monitoring of food spoilage when taking the concentration of the biogenic amine (HI) as the input signal.
Background
Molecular subtyping of triple‐negative breast cancers (TNBCs) via gene expression profiling is essential for understanding the molecular essence of this heterogeneous disease and for ...guiding individualized treatment. We aim to devise a clinically practical method based on immunohistochemistry (IHC) for the molecular subtyping of TNBCs.
Materials and Methods
By analyzing the RNA sequencing data on TNBCs from Fudan University Shanghai Cancer Center (FUSCC) (n = 360) and The Cancer Genome Atlas data set (n = 158), we determined markers that can identify specific molecular subtypes. We performed immunohistochemical staining on tumor sections of 210 TNBCs from FUSCC, established an IHC‐based classifier, and applied it to another two cohorts (n = 183 and 214).
Results
We selected androgen receptor (AR), CD8, FOXC1, and DCLK1 as immunohistochemical markers and classified TNBCs into five subtypes based on the staining results: (a) IHC‐based luminal androgen receptor (IHC‐LAR; AR‐positive +), (b) IHC‐based immunomodulatory (IHC‐IM; AR‐negative −, CD8+), (c) IHC‐based basal‐like immune‐suppressed (IHC‐BLIS; AR−, CD8−, FOXC1+), (d) IHC‐based mesenchymal (IHC‐MES; AR−, CD8−, FOXC1−, DCLK1+), and (e) IHC‐based unclassifiable (AR−, CD8−, FOXC1−, DCLK1−). The κ statistic indicated substantial agreement between the IHC‐based classification and mRNA‐based classification. Multivariate survival analysis suggested that our IHC‐based classification was an independent prognostic factor for relapse‐free survival. Transcriptomic data and pathological observations implied potential treatment strategies for different subtypes. The IHC‐LAR subtype showed relative activation of HER2 pathway. The IHC‐IM subtype tended to exhibit an immune‐inflamed phenotype characterized by the infiltration of CD8+ T cells into tumor parenchyma. The IHC‐BLIS subtype showed high expression of a VEGF signature. The IHC‐MES subtype displayed activation of JAK/STAT3 signaling pathway.
Conclusion
We developed an IHC‐based approach to classify TNBCs into molecular subtypes. This IHC‐based classification can provide additional information for prognostic evaluation. It allows for subgrouping of TNBC patients in clinical trials and evaluating the efficacy of targeted therapies within certain subtypes.
Implications for Practice
An immunohistochemistry (IHC)‐based classification approach was developed for triple‐negative breast cancer (TNBC), which exhibited substantial agreement with the mRNA expression‐based classification. This IHC‐based classification (a) allows for subgrouping of TNBC patients in large clinical trials and evaluating the efficacy of targeted therapies within certain subtypes, (b) will contribute to the practical application of subtype‐specific treatment for patients with TNBC, and (c) can provide additional information beyond traditional prognostic factors in relapse prediction.
This article describes an immunohistochemistry‐based approach to classification of triple‐negative breast cancers into molecular subtypes for purposes of the translation of TNBC molecular classification into clinical practice.
The intrinsic hydrophobicity and limited light absorption especially in the near‐infrared (NIR) region of porous organic polymers are two bottlenecks impeding their applications in solar steam ...generation (SSG). Herein, we develop a 1,4,5,8‐tetrakis(phenylamino)anthracene‐9,10‐dione (TPAD)‐based covalent organic framework (COF) (TPAD‐COF) featuring both superhydrophilicity and broad light absorption covering from the entire UV/Vis to NIR regions for SSG. TPAD‐COF serving as a highly efficient photothermal conversion material without any additives displays an excellent water evaporation of 1.42 kg m−2 h−1 and achieves a high energy conversion efficiency of 94 % under 1 sun irradiation. Further extension of the light absorption range of the TPAD‐based COF is realized through post‐synthetic modification by chelating BF2 moieties. Systematic control experiments and analysis confirm that the hydrophilicity of photothermal conversion materials plays a more dominant role in the current TPAD‐based COFs for SSG.
A 1,4,5,8‐tetrakis(phenylamino)anthr‐acene‐9,10‐dione (TPAD)‐based covalent organic framework (COF) with both superhydrophilicity and broad light absorption covering the entire UV/Vis to NIR regions is developed for solar steam generation (SSG) and delivers an excellent water evaporation up to 1.42 kg m−2 h−1 with a high energy conversion efficiency of 94 % under one sun irradiation.
PDF
