Electrochemiluminescence (ECL) plays a key role in analysis and sensing because of its high sensitivity and low background. Its wide applications are however limited by a lack of highly tunable ECL ...luminophores. Here we develop a scalable method to design ECL emitters of covalent organic frameworks (COFs) in aqueous medium by simultaneously restricting the donor and acceptor to the COFs' tight electron configurations and constructing high-speed charge transport networks through olefin linkages. This design allows efficient intramolecular charge transfer for strong ECL, and no exogenous poisonous co-reactants are needed. Olefin-linked donor-acceptor conjugated COFs, systematically synthesized by combining non-ECL active monomers with C
or C
symmetry, exhibit strong ECL signals, which can be boosted by increasing the chain length and conjugation of monomers. The present concept demonstrates that the highly efficient COF-based ECL luminophores can be precisely designed, providing a promising direction toward COF-based ECL phosphors.
Covalent organic frameworks (COFs) show potentials in prominent photoelectric responses by judicious structural design. However, from the selections of monomers and condensation reactions to the ...synthesis procedures, the acquisition of photoelectric COFs has to meet overmuch high conditions, limiting the breakthrough and modulation in photoelectric responses. Herein, the study reports a creative "lock-key model" based on molecular insertion strategy. A COF with suitable cavity size, TP-TBDA, is used as the host to load guests. Merely through the volatilization of mixed solution, TP-TBDA and guests can be spontaneously assembled via non-covalent interactions (NCIs) to produce molecular-inserted COFs (MI-COFs). The NCIs between TP-TBDA and guests acted as a bridge to facilitate charge transfer in MI-COFs, unlocking the photoelectric responses of TP-TBDA. By exploiting the controllability of NCIs, the MI-COFs can realize the smart modulation of photoelectric responses by simply changing the guest molecule, thus avoiding the arduous selection of monomers and condensation reactions required by conventional COFs. The construction of molecular-inserted COFs circumvents complicated procedures for achieving performance improvement and modulation, providing a promising direction to construct late-model photoelectric responsive materials.
The fates of cadmium (Cd) and arsenic (As) in paddy fields are generally opposite; thus, the inconsistent transformation of Cd and As poses large challenges for their remediation. In this study, the ...impacts of zero valent iron (ZVI) and/or biochar amendments on Cd and As bioavailability were examined in pot trials with rice. Comparison with the untreated soil, both Cd and As accumulation in different rice tissues decreased significantly in the ZVI-biochar amendments and the Cd and As accumulation in rice decreased with increasing ZVI contents. In particular, the concentrations of Cd (0.15 ± 0.01 mg kg−1) and As (0.17 ± 0.01 mg kg−1) in rice grains were decreased by 93% and 61% relative to the untreated soil, respectively. A sequential extraction analysis indicated that with increasing Fe ratios in the ZVI-biochar mixtures, bioavailable Cd and As decreased, and the immobilized Cd and As increased. Furthermore, high levels of Fe, Cd, and As were detected in Fe plaque of the ZVI-biochar amendments in comparison with the single biochar or single ZVI amendments. The ZVI-biochar mixture may have a synergistic effect that simultaneously reduces Cd and As bioavailability by increasing the formation of amorphous Fe and Fe plaque for Cd and As immobilization. The single ZVI amendment significantly decreased As bioavailability, while the single biochar amendment significantly reduced the bioavailability of Cd compared with the combined amendments. Hence, using a ZVI-biochar mixture as a soil amendment could be a promising strategy for safely-utilizing Cd and As co-contaminated sites in the future.
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•The single zero valent iron amendment decreased the bioavailability of As.•The single biochar amendment reduced the bioavailability of Cd.•The ZVI-biochar amendments simultaneously reduced Cd and As bioavailability.•The Fe, Cd, and As in plaque increased significantly in the ZVI-biochar amendments.•The ZVI-biochar amendments increased the amorphous Fe oxides in soils.
Covalent organic frameworks (COFs) have been proposed for electrochemical energy storage, although the poor conductivity resulted from covalent bonds limits their practical performance. Here, we ...propose to introduce noncovalent bonds in COFs through a molecular insertion strategy for improving the conductivity of the COFs as supercapacitor. The synthesized COFs (MI−COFs) establish equilibriums between covalent bonds and noncovalent bonds, which construct a continuous charge transfer channel to enhance the conductivity. The rapid charge transfer rate enables the COFs to activate the redox sites, bringing about excellent electrochemical energy storage behavior. The results show that the MI−COFs exhibit much better performance in specific capacitance and capacity retention rate than those of most COFs‐based supercapacitors. Moreover, through simply altering inserted guests, the mode and strength of noncovalent bond can be adjusted to obtain different energy storage characteristics. The introduction of noncovalent bonds is an effective and flexible way to enhance and regulate the properties of COFs, providing a valuable direction for the development of novel COFs‐based energy storage materials.
A molecular insertion strategy is used by introducing non‐covalent interactions in COFs to form a continuous charge transfer channel and accelerate the charge transfer rate. Meanwhile, the enhanced conductivity activates the redox sites in the COF skeleton, resulting in excellent energy storage performance. In addition, the energy storage behavior can be accurately regulated by changing the type of insertion guests.
At present, poor stability and carrier transfer efficiency are the main problems that limit the development of perovskite‐based photoelectric technologies. In this work, hydrogen‐bonded ...cocrystal‐coated perovskite composite (PeNCs@NHS‐M) is easily obtained by inducing rapid crystallization of melamine (M) and N‐hydroxysuccinimide (NHS) with PeNCs as the nuclei. The outer NHS‐M cocrystal passivates the undercoordinated lead atoms by forming covalent bonds, thereby greatly reducing the trap density while maintaining good structure stability for perovskite nanocrystals. Moreover, benefiting from the interfacial covalent band linkage and long‐range ordered structures of cocrystals, the charge transfer efficiency is effectively enhanced and PeNCs@NHS−M displays superior photoelectric performance. Based on the excellent photoelectric performance and abundant active sites of PeNCs@NHS−M, photocatalytic reduction of uranium is realized. PeNCs@NHS−M exhibits U(VI) reduction removal capability of up to 810.1 mg g−1 in the presence of light. The strategy of cocrystals trapping perovskite nanocrystals provides a simple synthesis method for composites and opens up a new idea for simultaneously improving the stability and photovoltaic performance of perovskite.
The CsPbBr3 nanocrystals (PeNCs) are coated with hydrogen‐bonded cocrystals (N‐hydroxysuccinimide‐melamine, NHS‐M) to achieve defect passivation and structural stability enhancement. Moreover, this covalently linked heterostructure further promotes the electron transport of PeNCs and realizes the photocatalytic reduction of uranium through the binding sites on the cocrystal.
Carbon capture is a technology that can reduce emissions of greenhouse gases such as carbon dioxide. For carbon dioxide produced in the atmosphere or in other industries, captures and stores carbon ...dioxide through chemical or physical methods, or processes and utilizes the captured carbon dioxide in other ways, so as to reduce the content of carbon dioxide in the atmosphere. Utilizing the captured carbon dioxide to achieve economic benefits is an efficient and economical method for carbon capture. This article focuses on the analysis of the three fields of petrochemical, construction, and power industry. By using the captured carbon dioxide to generate specific additional energy, and then comparing the benefits of the additional energy, it can be concluded which aspects are developable. Through analysis and comparison, the limitations and prospects for development in the three fields of petrochemical industry, construction industry and power industry can be given. Especially in power industry, the use of carbon capture technology to capture carbon dioxide from exhaust gases and store it underground can reduce emissions by at least 90%. In conclusion, after comparing the three sectors of the petrochemical industry, the building industry and the power industry. It can be concluded that the objectives to be achieved by applying carbon capture technologies and utilising, the additional empowerment generated, are similar. All are aimed at reducing emissions, improving energy efficiency and achieving sustainable development.
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•Biochar amendment simultaneously increased microbial reduction of As(V) and Fe(III).•Biochar increased the abundance of Geobacter, Anaeromyxobacter and Clostridium.•The abundance of ...Geobacter transcripts closely tracked with As(V) contents.•The abundance of Clostridium transcripts closely tracked with Fe(III) contents.•Geobacter has a role in As(V) reduction while Clostridium was in Fe(III) reduction.
Although biochar has great potential for heavy metal removal from sediments or soils, its impact on arsenic biogeochemistry in contaminated paddy fields remains poorly characterized. In this study, anaerobic microcosms were established with arsenic-contaminated paddy soil to investigate arsenic transformation as well as the potentially active microbial community and their transcriptional activities in the presence of biochar. The results demonstrated that biochar can simultaneously stimulate microbial reduction of As(V) and Fe(III), releasing high levels of As(III) into the soil solution relative to the control. Total RNAs were extracted to profile the potentially active microbial communities, which suggested that biochar increased the abundance of arsenic- and iron-related bacteria, such as Geobacter, Anaeromyxobacter and Clostridium compared to the control. Reverse transcription, quantitative PCR (RT-qPCR) showed that the abundance of Geobacter transcripts were significantly stimulated by biochar throughout the incubation. Furthermore, significant positive correlations were observed between the abundance of Geobacter transcripts and As(V) concentrations, and between that of Clostridium transcripts and Fe(III) concentrations in biochar-amended microcosms. Our findings suggest that biochar can stimulate the activity of metal-reducing bacteria to promote arsenic mobility. The Geobacter may contribute to As(V) reduction in the presence of biochar, while Clostridium has a role in Fe(III) reduction.
The recent decades have seen a surge of new nanomaterials designed for efficient drug delivery. DNA nanotechnology has been developed to construct sophisticated 3D nanostructures and artificial ...molecular devices that can be operated at the nanoscale, giving rise to a variety of programmable functions and fascinating applications. In particular, DNA‐origami nanostructures feature rationally designed geometries and precise spatial addressability, as well as marked biocompatibility, thus providing a promising candidate for drug delivery. Here, the recent successful efforts to employ self‐assembled DNA‐origami nanostructures as drug‐delivery vehicles are summarized. The remaining challenges and open opportunities are also discussed.
Structural DNA nanotechnology provides a biocompatible platform to construct customized nanocarriers. Recent developments of DNA‐origami‐based drug‐delivery systems are summarized. Multifunctional, highly tunable, and biologically amenable, DNA‐based nanomaterials will provide powerful strategies to understand and treat disease.
Multidrug resistance (MDR) is a major obstacle in the clinical treatment of cancer. Herein, a facile strategy is reported to construct a versatile DNA nanostructure as a co‐delivery vector of RNA ...interference (RNAi) and chemodrugs to combat multidrug‐resistant tumor (MCF‐7R) in vitro and in vivo. In the tailored nanocarrier, two linear small hairpin RNA (shRNA) transcription templates targeting MDR‐associated genes (gene of P‐glycoprotein, a typical drug efflux pump; and gene of survivin, a representative anti‐apoptotic protein) are precisely organized in the chemodrug (doxorubicin, DOX) pre‐loaded DNA origami. With the incorporation of active targeting and controlled‐release elements, these multifunctional DNA nanocarriers can successfully enter the target MCF‐7R cells and synergistically inhibit tumor growth without apparent systemic toxicity. This tailored DNA nanoplatform, which combines RNAi therapy and chemotherapy, provides a new strategy for the treatment of multidrug‐resistant tumors.
A DNA nanoplatform‐based co‐delivery system containing two linear shRNA transcription templates against tumor‐associated genes (Pgp and survive) and a chemotherapeutic drug (doxorubicin, DOX) was constructed for synergistic therapy of multidrug resistant (MDR) tumors in vivo.
Organic substrates and biochar are important in controlling arsenic release from sediments and soils; however, little is known about their impact on arsenic-reducing bacteria and genes during arsenic ...transformation in flooded paddy soils. In this study, microcosm experiments were established to profile transcriptional activity of As(V)-respiring gene (arrA) and arsenic resistance gene (arsC) as well as the associated bacteria regulated by lactate and/or biochar in anaerobic arsenic-contaminated paddy soils. Chemical analyses revealed that lactate as the organic substrate stimulated microbial reduction of As(V) and Fe(III), which was simultaneously promoted by lactate+biochar, due to biochar’s electron shuttle function that facilitates electron transfer from bacteria to As(V)/Fe(III). Sequencing and phylogenetic analyses demonstrated that both arrA closely associated with Geobacter (>60%, number of identical sequences/number of the total sequences) and arsC related to Enterobacteriaceae (>99%) were selected by lactate and lactate+biochar. Compared with the lactate microcosms, transcriptions of the bacterial 16S rRNA gene, Geobacter spp., and Geobacter arrA and arsC genes were increased in the lactate+biochar microcosms, where transcript abundances of Geobacter and Geobacter arrA closely tracked with dissolved As(V) concentrations. Our findings indicated that lactate and biochar in flooded paddy soils can stimulate the active As(V)-respiring bacteria Geobacter species for arsenic reduction and release, which probably increases arsenic bioavailability to rice plants.
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