The tunable growth of metal–organic materials has implications for engineering particles and surfaces for diverse applications. Specifically, controlling the self‐assembly of metal–phenolic networks ...(MPNs), an emerging class of metal–organic materials, is challenging, as previous studies suggest that growth often terminates through kinetic trapping. Herein, kinetic strategies were used to temporally and spatially control MPN growth by promoting self‐correction of the coordinating building blocks through oxidation‐mediated MPN assembly. The formation and growth mechanisms were investigated and used to engineer films with microporous structures and continuous gradients. Moreover, reactive oxygen species generated by ultrasonication expedite oxidation and result in faster (ca. 30 times) film growth than that achieved by other MPN assembly methods. This study expands our understanding of metal–phenolic chemistry towards engineering metal–phenolic materials for various applications.
Kinetic assembly is an efficient strategy for rapidly and continuously growing metal–phenolic network materials. Using reactive oxygen species, films were grown about 30 times faster than with existing technologies. Furthermore, the films display unique microstructures and continuous film gradients, which are desirable properties for applications in drug delivery and separations.
Supramolecular complexation is a powerful strategy for engineering materials in bulk and at interfaces. Metal–phenolic networks (MPNs), which are assembled through supramolecular complexes, have ...emerged as suitable candidates for surface and particle engineering owing to their diverse properties. Herein, we examine the supramolecular dynamics of MPNs during thermal transformation processes. Changes in the local supramolecular network including enlarged pores, ordered aromatic packing, and metal relocation arise from thermal treatment in air or an inert atmosphere, enabling the engineering of metal–oxide networks (MONs) and metal–carbon networks, respectively. Furthermore, by integrating photo‐responsive motifs (i.e., TiO2) and silanization, the MONs are endowed with reversible superhydrophobic (>150°) and superhydrophilic (≈0°) properties. By highlighting the thermodynamics of MPNs and their transformation into diverse materials, this work offers a versatile pathway for advanced materials engineering.
Supramolecular metal–phenolic networks, consisting of metal ions coordinated with phenolic motifs, can undergo selective thermodynamic transformations into nanoporous structures, including metal–carbon networks and metal–oxide networks, with tunable network organization and surface wettability.
Functional coatings are of considerable interest because of their fundamental implications for interfacial assembly and promise for numerous applications. Universally adherent materials have recently ...emerged as versatile functional coatings; however, such coatings are generally limited to catechol, (ortho‐diphenol)‐containing molecules, as building blocks. Here, we report a facile, biofriendly enzyme‐mediated strategy for assembling a wide range of molecules (e.g., 14 representative molecules in this study) that do not natively have catechol moieties, including small molecules, peptides, and proteins, on various surfaces, while preserving the molecule's inherent function, such as catalysis (≈80 % retention of enzymatic activity for trypsin). Assembly is achieved by in situ conversion of monophenols into catechols via tyrosinase, where films form on surfaces via covalent and coordination cross‐linking. The resulting coatings are robust, functional (e.g., in protective coatings, biological imaging, and enzymatic catalysis), and versatile for diverse secondary surface‐confined reactions (e.g., biomineralization, metal ion chelation, and N‐hydroxysuccinimide conjugation).
The toolbox of metal–phenolic networks is expanded by enzyme‐mediated assembly, where a range of monophenols are converted into catechol‐containing molecules and cross‐linked by metal ions. This strategy preserves functionality of the monophenol precursors, while conferring benefits of catechol‐containing molecules (e.g., universal adhesion) to the networks.
Engineering coatings with precise physicochemical properties allows for control over the interface of a material and its interactions with the surrounding environment. However, assembling coatings ...with well‐defined properties on different material classes remains a challenge. Herein, we report a co‐assembly strategy to precisely control the structure and properties (e.g., thickness, adhesion, wettability, and zeta potential) of coatings on various materials (27 substrates examined) using quinone and polyamine building blocks. By increasing the length of the amine building blocks from small molecule diamines to branched amine polymers, we tune the properties of the films, including the thickness (from ca. 5 to ca. 50 nm), interfacial adhesion (0.05 to 5.54 nN), water contact angle (130 to 40°), and zeta potential (−42 to 28 mV). The films can be post‐functionalized through the in situ formation of diverse nanostructures, including nanoparticles, nanorods, and nanocrystals. Our approach provides a platform for the rational design of engineered, substrate‐independent coatings for various applications.
Coatings and thin films of amino‐quinone networks are prepared on various materials by a co‐assembly strategy using quinones and polyamines. Using different building blocks affords precise control over the structures and properties of the coatings, which can serve as multifunctional reaction platforms to synthesize nanoparticles on surfaces.
The manipulation of interfacial properties has broad implications for the development of high‐performance coatings. Metal–phenolic networks (MPNs) are an emerging class of responsive, adherent ...materials. Herein, host–guest chemistry is integrated with MPNs to modulate their surface chemistry and interfacial properties. Macrocyclic cyclodextrins (host) are conjugated to catechol or galloyl groups and subsequently used as components for the assembly of functional MPNs. The assembled cyclodextrin‐based MPNs are highly permeable (even to high molecular weight polymers: 250–500 kDa), yet they specifically and noncovalently interact with various functional guests (including small molecules, polymers, and carbon nanomaterials), allowing for modular and reversible control over interfacial properties. Specifically, by using either hydrophobic or hydrophilic guest molecules, the wettability of the MPNs can be readily tuned between superrepellency (>150°) and superwetting (ca. 0°).
Networking: The synthesis of host phenolic building blocks, consisting of macrocyclic host rings and phenolic coordinating functions, enables the rapid assembly of adherent conformal metal–phenolic network coatings on diverse substrates with modular and tunable interfacial properties using host–guest chemistry.
Abstract
Circular RNAs (circRNAs) have been implicated in cancer progression through largely unknown mechanisms. Herein, we identify an
N
6
-methyladenosine (m
6
A) modified circRNA, circNSUN2, ...frequently upregulated in tumor tissues and serum samples from colorectal carcinoma (CRC) patients with liver metastasis (LM) and predicts poorer patient survival. The upregulated expression of circNSUN2 promotes LM in PDX metastasis models in vivo and accelerates cancer cells invasion in vitro. Importantly,
N
6
-methyladenosine modification of circNSUN2 increases export to the cytoplasm. By forming a circNSUN2/IGF2BP2/
HMGA2
RNA-protein ternary complex in the cytoplasm, circNSUN2 enhances the stability of
HMGA2
mRNA to promote CRC metastasis progression. Clinically, the upregulated expressions of circNSUN2 and
HMGA2
are more prevalent in LM tissues than in primary CRC tissues. These findings elucidate that
N
6
-methyladenosine modification of circNSUN2 modulates cytoplasmic export and stabilizes
HMGA2
to promote CRC LM, and suggest that circNSUN2 could represent a critical prognostic marker and/or therapeutic target for the disease.
Summary
The finite difference discretization of the spatial fractional diffusion equations gives discretized linear systems whose coefficient matrices have a diagonal‐plus‐Toeplitz structure. For ...solving these diagonal‐plus‐Toeplitz linear systems, we construct a class of diagonal and Toeplitz splitting iteration methods and establish its unconditional convergence theory. In particular, we derive a sharp upper bound about its asymptotic convergence rate and deduct the optimal value of its iteration parameter. The diagonal and Toeplitz splitting iteration method naturally leads to a diagonal and circulant splitting preconditioner. Analysis shows that the eigenvalues of the corresponding preconditioned matrix are clustered around 1, especially when the discretization step‐size h is small. Numerical results exhibit that the diagonal and circulant splitting preconditioner can significantly improve the convergence properties of GMRES and BiCGSTAB, and these preconditioned Krylov subspace iteration methods outperform the conjugate gradient method preconditioned by the approximate inverse circulant‐plus‐diagonal preconditioner proposed recently by Ng and Pan (M.K. Ng and J.‐Y. Pan, SIAM J. Sci. Comput. 2010;32:1442‐1464). Moreover, unlike this preconditioned conjugate gradient method, the preconditioned GMRES and BiCGSTAB methods show h‐independent convergence behavior even for the spatial fractional diffusion equations of discontinuous or big‐jump coefficients.
Hybrid conformal coatings, such as metal–phenolic networks (MPNs) that are constructed from the coordination-driven assembly of natural phenolic ligands, are of interest in areas including ...biomedicine, separations, and energy. To date, most MPN coatings have been prepared by immersing substrates in solutions containing the phenolic ligands and metal ions, which is a suitable method for coating small or flexible objects. In contrast, more industrially relevant methods for coating and patterning large substrates, such as spray assembly, have been explored to a lesser extent toward the fabrication of MPNs, particularly regarding the effect of process variables on MPN growth. Herein, a spray assembly method was used to fabricate MPN coatings with various phenolic building blocks and metal ions and their formation and patterning were explored for different applications. Different process parameters including solvent, pH, and metal–ligand pair allowed for control over the film properties such as thickness and roughness. On the basis of these investigations, a potential route for the formation of spray-assembled MPN films was proposed. Conditions favoring the formation of bis complexes could produce thicker coatings than those favoring the formation of mono or tris complexes. Finally, the spray-assembled MPNs were used to generate superhydrophilic membranes for oil–water separation and colorless films for UV shielding. The present study provides insights into the chemistry of MPN assembly and holds promise for advancing the fabrication of multifunctional hybrid materials.
Metastasis causes the vast majority of colorectal carcinoma (CRC)-related deaths. However, little is known about the specific traits and underlying mechanisms of metastasis-initiating cells in ...primary CRC. And whether or not circular RNAs (circRNAs) take part in this particular event remain not adequately stated yet.
A screening method based on Transwell assay was first applied to build CRC subgroups with different metastatic potential. High throughput RNA sequencing was used to find out novel metastatic drivers in CRC metastasis-initiating step. A series of in vitro and in vivo assays were further applied to elucidate the functions and underlying molecular mechanisms of circRNAs in CRC metastasis.
A circRNA consisting of exon 8-11 of LONP2, termed as circLONP2, was upregulated in metastasis-initiating CRC subgroups. Aberrant higher expression of circLONP2 was observed in primary CRC tissues with established metastasis, and along the invasive margin in metastatic site. High expression of circLONP2 predicted unfavorable overall survival. Functional studies revealed that circLONP2 could enhance the invasiveness of CRC cells in vitro, and targeting circLONP2 through anti-sense oligonucleotide (ASO) dramatically reduced the penetrance of metastasis to foreign organs in vivo. Mechanically, circLONP2 directly interacted with and promoted the processing of primary microRNA-17 (pri-miR-17), through recruiting DiGeorge syndrome critical region gene 8 (DGCR8) and Drosha complex in DDX1-dependent manner. Meanwhile, upregulated mature miR-17-5p could be assembled into exosomes and internalized by neighboring cells to enhance their aggressiveness.
Our data indicate that circLONP2 acts as key metastasis-initiating molecule during CRC progression through modulating the intracellular maturation and intercellular transfer of miR-17, resulting in dissemination of metastasis-initiating ability in primary site and acceleration of metastasis formation in foreign organs. circLONP2 could serve as an effective prognostic predictor and/or novel anti-metastasis therapeutic target in CRC treatment.
According to the EPOC study, chemotherapy could improve 5-year disease-free survival of stage IV colon cancer patients by 8.1%. However, more molecular biomarkers are required to identify patients ...who need neoadjuvant chemotherapy. DENND2D expression was evaluated by immunohistochemistry in 181 stage IV colon cancer patients. The prognosis was better for patients with DENND2D expression than patients without DENND2D expression (5-year overall survival OS: 42% vs. 12%, p = 0.038; 5-year disease-free survival: 20% vs. 10%, p = 0.001). Subgroup analysis of the DENND2D-negative group showed that patients treated with neoadjuvant chemotherapy achieved longer OS than patients without neoadjuvant chemotherapy (RR = 0.179; 95% CI = 0.054-0.598; p = 0.003). DENND2D suppressed CRC proliferation in vitro and in vivo. Downregulation of DENND2D also promoted metastasis to distant organs in vivo. Mechanistically, DENND2D suppressed the MAPK pathway in CRC. Colon cancer patients who were DENND2D negative always showed a worse prognosis and were more likely to benefit from neoadjuvant chemotherapy. DENND2D may be a new prognostic factor and a predictor of the need for neoadjuvant chemotherapy in stage IV colon cancer.
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