A universal method to grow polymers on MOF surfaces with well-defined thickness, sequence and functionality.

Construction of thermally and chemically robust metal−organic frameworks (MOFs) is highly desirable for postcombustion CO 2 capture from flue gas containing water vapor and other acidic gases. Here we report a strategy based on appending amino groups to the triazolate linkers of MOFs to achieve exceptional chemical stability against aqueous, acidic, and basic conditions. These MOFs exhibit not only CO 2 /N 2 thermodynamic adsorption selectivity as high as 120 but also CO 2 /H 2 O kinetic adsorption selectivity up to 70, featuring distinct adsorptive sites at the channel center for CO 2 and at the corner for H 2 O, respectively. The best performing MOF in this series features low regeneration energy, high CO 2 capture utility under humid conditions, and decent cycling performance for mimic flue gas.M etal−organic frameworks (MOFs) are prominent solid adsorbents that combine well-defined adsorptive sites, fine-tuned pore sizes, and decorated interior functionalities to achieve strong binding affinity, high selectivity, large capacity, and low regeneration energy for CO 2 capture. 1−3 However, with respect to practical postcombustion capture, concerns arise from the competitive adsorption of H 2 O against CO 2 4

Adhesive curli nanofibers, bacterial biofilms' major protein component, were utilized to mediate the growth of MOFs on various polymeric substrates.

A major challenge in material design is to couple nanoscale molecular and supramolecular events into desired chemical, physical, and mechanical properties at the macroscopic scale. Here, a novel self‐assembled DNA crystal actuator is reported, which has reversible, directional expansion and contraction for over 50 μm in response to versatile stimuli, including temperature, ionic strength, pH, and redox potential. The macroscopic actuation is powered by cooperative dissociation or cohesion of thousands of DNA sticky ends at the designed crystal contacts. The increase in crystal porosity and cavity in the expanded state dramatically enhances the crystal capability to accommodate/encapsulate nanoparticles/proteins, while the contraction enables a “sponge squeezing” motion for releasing nanoparticles. This crystal actuator is envisioned to be useful for a wide range of applications, including powering self‐propelled robotics, sensing subtle environmental changes, constructing functional hybrid materials, and working in drug controlled‐release systems.

Sequence-selective recognition of DNA duplexes is important for a wide range of applications including regulating gene expression, drug development, and genome editing. Many small molecules can bind DNA duplexes with sequence selectivity. It remains as a challenge how to reliably and conveniently obtain the detailed structural information on DNA–molecule interactions because such information is critically needed for understanding the underlying rules of DNA–molecule interactions. If those rules were understood, we could design molecules to recognize DNA duplexes with a sequence preference and intervene in related biological processes, such as disease treatment. Here, we have demonstrated that DNA crystal engineering is a potential solution. A molecule-binding DNA sequence is engineered to self-assemble into highly ordered DNA crystals. An X-ray crystallographic study of molecule–DNA cocrystals reveals the structural details on how the molecule interacts with the DNA duplex. In this approach, the DNA will serve two functions: (1) being part of the molecule to be studied and (2) forming the crystal lattice. It is conceivable that this method will be a general method for studying drug/peptide–DNA interactions. The resulting DNA crystals may also find use as separation matrices, as hosts for catalysts, and as media for material storage.

This manuscript introduces geometry as a means to program the tile-based DNA self-assembly in two and three dimensions. This strategy complements the sequence-focused programmable assembly. DNA crystal assembly critically relies on intermotif, sticky-end cohesion, which requires complementarity not only in sequence but also in geometry. For DNA motifs to assemble into crystals, they must be associated with each other in the proper geometry and orientation to ensure that geometric hindrance does not prevent sticky ends from associating. For DNA motifs with exactly the same pair of sticky-end sequences, by adjusting the length (thus, helical twisting phase) of the motif branches, it is possible to program the assembly of these distinct motifs to either mix with one another, to self-sort and consequently separate from one another, or to be alternatingly arranged. We demonstrate the ability to program homogeneous crystals, DNA “alloy” crystals, and definable grain boundaries through self-assembly. We believe that the integration of this strategy and conventional sequence-focused assembly strategy could further expand the programming versatility of DNA self-assembly.

Non‐canonical interactions in DNA remain under‐explored in DNA nanotechnology. Recently, many structures with non‐canonical motifs have been discovered, notably a hexagonal arrangement of typically rhombohedral DNA tensegrity triangles that forms through non‐canonical sticky end interactions. Here, we find a series of mechanisms to program a hexagonal arrangement using: the sticky end sequence; triangle edge torsional stress; and crystallization condition. We showcase cross‐talking between Watson–Crick and non‐canonical sticky ends in which the ratio between the two dictates segregation by crystal forms or combination into composite crystals. Finally, we develop a method for reconfiguring the long‐range geometry of formed crystals from rhombohedral to hexagonal and vice versa. These data demonstrate fine control over non‐canonical motifs and their topological self‐assembly. This will vastly increase the programmability, functionality, and versatility of rationally designed DNA constructs.

Small, single-stranded DNA (ssDNA) circles have many applications, such as templating rolling circle amplification (RCA), capturing microRNAs, and scaffolding DNA nanostructures. However, it is challenging to prepare such ssDNA circles, particularly when the DNA size becomes very small (e.g. a 20 nucleotide (nt) long ssDNA circle). Often, such short ssDNA dominantly form concatemers (either linear or circular) due to intermolecular ligation, instead of forming monomeric ssDNA circles by intramolecular ligation. Herein, a simple method to overcome this problem by designing the complementary linker molecules is reported. It is demonstrated that ssDNA, as short as 16 nts, can be enzymatically ligated (by the commonly used T4 DNA ligase) into monomeric ssDNA circles at high concentration (100 μM) with high yield (97 %). This method does not require any special sequence, thus, it is expected to be generally applicable. The experimental protocol is identical to regular DNA ligation, thus, is expected to be user friendly for general chemists and biologists.