Customized Self-Assembled Gold Nanoparticle-DNA Origami Composite Templates for Shape-Directed Growth of Plasmonic Structures.

The metal plasmonic nanostructure has the optical property of plasmon resonance, which holds great potential for development in nanophotonics, bioelectronics, and molecular detection. However, developing a general and straightforward method to prepare metal plasmonic nanostructures with a controllable size and morphology still poses a challenge. Herein, we proposed a synthesis strategy that utilized a customizable self-assembly template for shape-directed growth of metal structures. We employed gold nanoparticles (AuNPs) as connectors and DNA nanotubes as branches, customizing gold nanoparticle-DNA origami composite nanostructures with different branches by adjusting the assembly ratio between the connectors and branches. Subsequently, various morphologies of plasmonic metal nanostructures were created using this template shape guided strategy, which exhibited enhancement of surface-enhanced Raman scattering (SERS) signals. This strategy provides a new approach for synthesizing metallic nanostructures with multiple morphologies and opens up another possibility for the development of customizable metallic plasmonic structures with broader applications.

Highly intense NIR emissive Cu4Pt2 bimetallic clusters featuring Pt(i)-Cu4-Pt(i) sandwich kernel.

Metal nanoclusters (NCs) capable of near-infrared (NIR) photoluminescence (PL) are gaining increasing interest for their potential applications in bioimaging, cell labelling, and phototherapy. However, the limited quantum yield (QY) of NIR emission in metal NCs, especially those emitting beyond 800 nm, hinders their widespread applications. Herein, we present a bright NIR luminescence (PLQY up to 36.7%, ∼830 nm) bimetallic Cu4Pt2 NC, [Cu4Pt2(MeO-C6H5-C[triple bond, length as m-dash]C)4(dppy)4]2+ (dppy = diphenyl-2-pyridylphosphine), with a high yield (up to 67%). Furthermore, by modifying the electronic effects of R in RC[triple bond, length as m-dash]C- (R = MeO-C6H5, F-C6H5, CF3-C6H5, Nap, and Biph), we can effectively modulate phosphorescence properties, including the PLQY, emission wavelength, and excited state decay lifetime. Experimental and computational studies both demonstrate that in addition to the electron effects of substituents, ligand modification enhances luminescence intensity by suppressing non-radiation transitions through intramolecular interactions. Simultaneously, it allows the adjustment of emitting wavelengths by tuning the energy gaps and first excited triplet states through intermolecular interactions of ligand substituents. This study provides a foundation for rational design of the atomic-structures of alloy metal NCs to enhance their PLQY and tailor the PL wavelength of NIR emission.

Conductive Metal-Organic Framework with Superior Redox Activity as a Stable High-Capacity Anode for High-Temperature K-Ion Batteries.

High-temperature rechargeable batteries are essential for energy storage in elevated-temperature situations. Due to the resource abundance of potassium, high-temperature K-ion batteries are drawing increasing research interest. However, raising the working temperature would aggravate the chemical and mechanical instability of the KIB anode, resulting in very fast capacity fading, especially when high capacity is pursued. Here, we demonstrated that a porous conductive metal-organic framework (MOF), which is constructed by N-rich aromatic molecules and CuO4 units via π-d conjugation, could provide multiple accessible redox-active sites and promised robust structure stability for efficient potassium storage at high temperatures. Even working at 60 °C, this MOF anode could deliver high initial capacity (455 mAh g-1), impressive rate, and extraordinary cyclability (96.7% capacity retention for 1600 cycles), which is much better than those of reported high-temperature KIB anodes. The mechanistic study revealed that C═N groups and CuO4 units contributed abundant redox-active sites; the synergistic effect of π-d conjugated character and reticular porous architecture facilitated the K+/e- transport and ensured an insoluble electrode with small volume deformation, thus achieving stable high-capacity potassium storage.

Precise Post-Synthetic Modification of Heterometal-Organic Capsules for Selectively Encapsulating Tetrahedral Anions.

Post-synthetic modification plays a crucial role in precisely adjusting the structure and functions of advanced materials. Herein, we report the self-assembly of a tubular heterometallic Pd3Cu6L16 capsule that incorporates Pd(II) and CuL1 metalloligands. This capsule undergoes further modification with two tridentate anionic ligands (L2) to afford a bicapped Pd3Cu6L16L22 capsule with an Edshammer polyhedral structure. By employing transition metal ions, acid, and oxidation agents, the bicapped capsule can be converted into an uncapped one. This uncapped form can then revert back to the bicapped structure on the addition of Br- ions and a base. Interestingly, introducing Ag+ ions leads to the removal of one L2 ligand from the bicapped capsule, yielding a mono-capped Pd3Cu6L16L2 structure. Furthermore, the size of the anions critically influences the precise control over the post-synthetic modifications of the capsules. It was demonstrated that these capsules selectively encapsulate tetrahedral anions, offering a novel approach for the design of intelligent molecular delivery systems.

Reversible modulation of interlayer stacking in 2D copper-organic frameworks for tailoring porosity and photocatalytic activity.

The properties of two-dimensional covalent organic frameworks (2D COFs), including porosity, catalytic activity as well as electronic and optical properties, are greatly affected by their interlayer stacking structures. However, the precise control of their interlayer stacking mode, especially in a reversible fashion, is a long-standing and challenging pursuit. Herein, we prepare three 2D copper-organic frameworks, namely JNM-n (n = 7, 8, and 9). Interestingly, the reversible interlayer sliding between eclipsed AA stacking (i.e., JNM-7-AA and JNM-8-AA) and staggered ABC stacking (i.e., JNM-7-ABC and JNM-8-ABC) can be achieved through environmental stimulation, which endows reversible encapsulation and release of lipase. Importantly, JNM-7-AA and JNM-8-AA exhibit a broader light absorption range, higher charge-separation efficiency, and higher photocatalytic activity for sensitizing O2 to 1O2 and O2•- than their ABC stacking isostructures. Consequently, JNM-8-AA deliver significantly enhanced photocatalytic activities for oxidative cross-coupling reactions compared to JNM-8-ABC and other reported homogeneous and heterogeneous catalysts.

DNA-Based Gold Nanoparticle Assemblies: From Structure Constructions to Sensing Applications.

Gold nanoparticles (Au NPs) have become one of the building blocks for superior assembly and device fabrication due to the intrinsic, tunable physical properties of nanoparticles. With the development of DNA nanotechnology, gold nanoparticles are organized in a highly precise and controllable way under the mediation of DNA, achieving programmability and specificity unmatched by other ligands. The successful construction of abundant gold nanoparticle assembly structures has also given rise to the fabrication of a wide range of sensors, which has greatly contributed to the development of the sensing field. In this review, we focus on the progress in the DNA-mediated assembly of Au NPs and their application in sensing in the past five years. Firstly, we highlight the strategies used for the orderly organization of Au NPs with DNA. Then, we describe the DNA-based assembly of Au NPs for sensing applications and representative research therein. Finally, we summarize the advantages of DNA nanotechnology in assembling complex Au NPs and outline the challenges and limitations in constructing complex gold nanoparticle assembly structures with tailored functionalities.

Pyrazine Functionalization in Eu-MOF for Exclusive Ratiometric Luminescence Sensing of PO43.

Single-emission luminescence sensors are less than satisfactory for complex systems due to their susceptibility to environmental disturbances. Lanthanum-based metal-organic frameworks (Ln-MOFs) with highly stable ratiometric dual-emission are regarded as promising luminescence probes owing to their fascinating ligand-to-metal energy transfer behaviors (also known as the antenna effect). Herein, we report the synthesis of a pair of isostructural europium-based MOFs (termed JNU-219 and JNU-220) by utilizing two X-shaped tetracarboxylate linkers, 4,4',4″,4‴-benzene-2,3,5,6-tetrayl-tetrabenzoate (BTEB) and 4,4',4″,4‴-pyrazine-2,3,5,6-tetrayl-tetrabenzoate (BTTB). Both JNU-219 and JNU-220 present the characteristic red luminescence of Eu3+, yet the pyrazine functionalization of the BTTB linker renders JNU-220 with significantly increased luminescence emission, almost 30 times that of JNU-219. As a result, the detection limit of JNU-220 for the ratiometric luminescence sensing of PO43- was determined to be as low as 0.22 µM, which is far superior to those of other reported MOF materials. Additionally, we demonstrate the excellent stability and reusability of JNU-220, further verifying its potential as a robust ratiometric luminescence probe.

Gold(I)-Organic Frameworks as Catalysts for Carboxylation of Alkynes with CO2.

Construction of gold-based metal-organic frameworks (Au-MOFs) would bring the merits of gold chemistry into MOFs. However, it still remains challenging because gold cations are easily reduced to metallic gold under solvothermal conditions. Herein, we present the first example of Au-MOFs prepared from the networking of cyclic trinuclear gold(I) complexes by formal transimination reaction in a rapid (<15 min) and scalable (up to 1 g) fashion under ambient condition. The Au-MOFs feature uniform porosity, high crystallinity, and superior chemical stability toward base (i.e., 20 M NaOH). With open Au(I) sites in the skeleton, the Au-MOFs as heterogeneous catalysts delivered good performance and substrate tolerance for the carboxylation reactions of alkynes with CO2. This work demonstrates a facile approach to reticularly synthesize Au-MOFs by combining the coordination and dynamic covalent chemistry.

A Self-Assembled Capsule for Propylene/Propane Separation.

The development of energy-saving technology for the efficient separation of olefin and paraffin is highly important for the chemical industry. Herein, we report a self-assembled Fe4 L6 capsule containing a hydrophobic cavity, which can be used to encapsulate and separate propylene/propane. The successful encapsulation of propylene and propane by the Fe4 L6 cage in a water solution was documented by NMR spectroscopy. The binding constants K for the Fe4 L6 cage toward propylene and propane were determined to be (5.0±0.1)×103  M-1 and (2.1±0.7)×104  M-1 in D2 O at 25 °C, respectively. Experiments and theoretical studies revealed that the cage exhibited multiple weak interactions with propylene and propane. The polymer-grade propylene (>99.5 %) can be obtained from a mixture of propylene and propane by using the Fe4 L6 cage as a separation material in a U-shaped glass tube. This work provides a new strategy for the separation of olefin/paraffin.

Regulation of recombinant humanized collagen on HAP growth and its molecule simulation.

Hydroxyapatite (HAP) in natural bone is formed under the regulation of natural collagen I. Here, we report how recombinant humanized collagen I (rhCol I) regulates the growth of HAP nanocrystals in a long belt shape 100-150 nm in width and 200-300 nm in length. MD simulation results showed that the interactions between rhCol I and the (001), (100), and (211) planes of HAP mainly contributed to the electrostatic force and van der Waals forces via COO⋯Ca, -NH⋯Ca, CH⋯OPO3, and NH⋯OPO3 bonds, respectively. On the (001) plane, the interaction between -COO- and Ca was stronger than on the (100) and (211) planes, resulting in a large electrostatic force, which inhibited the growth of the (001) plane. The lowest energy of adsorption to the (211) plane resulted in the preferential growth of the (211) plane due to the weakest interaction with rhCol I. The detailed correlation between HAP and rhCol I could explain HAP growth under regulation by rhCol I. This study provides a reference for the bio-application of recombinant collagen.

Circularly polarized chemiluminescence from planar chiral bis(adamantylidene-1,2-dioxetane)s.

Bis(adamantylidene-1,2-dioxetane), upon conjugation to a planar chiral scaffold of [2.2]paracyclophane, gave chemical-triggerable circularly polarized chemiluminescence with a dissymmetry factor of 1.1 × 10-3 scale, to which exciton chirality upon chemiexcitation was assigned as the origin.

Linker Engineering for Reactive Oxygen Species Generation Efficiency in Ultra-Stable Nickel-Based Metal-Organic Frameworks.

Interfacial charge transfer on the surface of heterogeneous photocatalysts dictates the efficiency of reactive oxygen species (ROS) generation and therefore the efficiency of aerobic oxidation reactions. Reticular chemistry in metal-organic frameworks (MOFs) allows for the rational design of donor-acceptor pairs to optimize interfacial charge-transfer kinetics. Herein, we report a series of isostructural fcu-topology Ni8-MOFs (termed JNU-212, JNU-213, JNU-214, and JNU-215) with linearly bridged bipyrazoles as organic linkers. These crystalline Ni8-MOFs can maintain their structural integrity in 7 M NaOH at 100 °C for 24 h. Experimental studies reveal that linker engineering by tuning the electron-accepting capacity of the pyrazole-bridging units renders these Ni8-MOFs with significantly improved charge separation and transfer efficiency under visible-light irradiation. Among them, the one containing a benzoselenadiazole unit (JNU-214) exhibits the best photocatalytic performance in the aerobic oxidation of benzylamines with a conversion rate of 99% in 24 h. Recycling experiments were carried out to confirm the stability and reusability of JNU-214 as a robust heterogeneous catalyst. Significantly, the systematic modulation of the electron-accepting capacity of the bridging units in donor-acceptor-donor MOFs provides a new pathway to develop viable noble-metal-free heterogeneous photocatalysts for aerobic oxidation reactions.

Achiral Au(I) Cyclic Trinuclear Complexes with High-Efficiency Circularly Polarized Near-Infrared TADF.

Realizing high photoluminescence quantum yield (PLQY) in the near-infrared (NIR) region is challenging and valuable for luminescent material, especially for thermally activated delay fluorescence (TADF) material. In this work, we report two achiral cyclic trinuclear Au(I) complexes, Au3 (4-Clpyrazolate)3 and Au3 (4-Brpyrazolate)3 (denoted as Cl-Au and Br-Au), obtained through the reaction of 4-chloro-1H-pyrazole and 4-bromo-1H-pyrazole with Au(I) salts, respectively. Both Cl-Au and Br-Au exhibit TADF with high PLQY (>70 %) in the NIR I (700-900 nm) (λmax = 720 nm) region, exceeding other NIR-TADF emitters in the solid state. Photophysical experiments and theoretical calculations confirmed the efficient NIR-TADF properties of Cl-Au and Br-Au were attributed to the small energy gap ΔE(S1-T2) (S = singlet, T = triplet) and the large spin-orbital coupling induced by ligand-to-metal-metal charge transfer of molecular aggregations. In addition, both complexes crystallize in the achiral Pna21 space group (mm2 point group) and are circularly polarized light (CPL) active with maxima luminescent dissymmetry factor |glum | of 3.4 × 10-3 (Cl-Au) and 2.7 × 10-3 (Br-Au) for their crystalline powder samples, respectively. By using Cl-Au as the emitting ink, 3D-printed luminescent logos are fabricated, which own anti-counterfeiting functions due to its CPL behavior dependent on the crystallinity.

Inhalable pH-responsive DNA tetrahedron nanoplatform for boosting anti-tumor immune responses against metastatic lung cancer.

Despite advancements in the treatment of pulmonary cancer, the existence of mucosal barriers in lung still hampered the penetration and diffusion of therapeutic agents and greatly limited the therapeutic benefits. In this work, we reported a novel inhalable pH-responsive tetrahedral DNA nanomachines with simultaneous delivery of immunomodulatory CpG oligonucleotide and PD-L1-targeting antagonistic DNA aptamer (CP@TDN) for efficient treatment of pulmonary metastatic cancer. By precisely controlling the ratios of CpG and PD-L1 aptamer, the obtained CP@TDN could specifically release PD-L1 aptamer to block PD-1/PD-L1 immune checkpoint axis in acidic tumor microenvironment, followed by endocytosis by antigen-presenting cells to generate anti-tumor immune activation and secretion of anti-tumor cytokines. Moreover, inhalation delivery of CP@TDN showed highly-efficient lung deposition with greatly enhanced intratumoral accumulation, ascribing to the DNA tetrahedron-mediated penetration of pulmonary mucosa. Resultantly, CP@TDN could significantly inhibit the growth of metastatic orthotopic lung tumors via the induction of robust antitumor responses. Therefore, our work presents an attractive approach by virtue of biocompatible DNA tetrahedron as the inhalation delivery system for effective treatment of metastatic lung cancer.

Dicationic Diimine Pt(II) Bis(N-heterocyclic allenylidene) Complexes: Extended Pt···Pt Chains, NIR Phosphorescence, and Chromonics.

Although square-planar Pt(II) complexes are well-known to self-assemble into supramolecules via noncovalent intermolecular Pt···Pt and/or π-π interactions, the self-assembly of dicationic Pt(II) complexes was scarce due to the electrostatic repulsive force. Herein, a series of dicationic diimine bis(N-heterocyclic allenylidene) Pt(II) complexes were synthesized and characterized. Close Pt···Pt and/or π-π contacts are observed in the crystals of these complexes. In particular, complexes 1·2PF6 and 2·2PF6 exhibit one-dimensional packing with extended Pt···Pt contacts of 3.302 and 3.240 Å, respectively. The photophysical properties of these complexes in the solution and solid state were investigated. NIR emission was recorded for complexes 1·2PF6 (λmax = 950 nm) and 2·2PF6 (λmax = 855 nm) in the solid state at 298 K. To explore the aggregate behaviors of these complexes, the counteranion PF6- was exchanged to the large lipophilic anion 2,3,4-tris(dodecyloxy)benzene sulfonate (LA-) and the hydrophilic anion Cl-. Complexes 1·2LA and 2·2LA or 1·2Cl and 2·2Cl could self-assemble with Pt···Pt and/or π-π interactions in the nonpolar or aqueous solutions as well. Further increasing the concentration of 1·2Cl and 2·2Cl in aqueous solution, chromonic mesophases with NIR emission (λmax = 988 nm) were obtained. DFT and TD-DFT calculations were performed to gain deep insight into the dication-dication packings and photophysical properties of the complexes. The σ-donating as well as π-accepting character of the N-heterocyclic allenylidene ligand endows complexes with rigid and electron-delocalized coplanar features, which are conducive to achieving the self-assembling processes associated with Pt···Pt and/or π-π interactions.

A BODIPY-Based 1D Covalent Organic Framework for Photocatalytic Aerobic Oxidation.

Covalent organic frameworks (COFs) as metal-free photocatalysts have attracted extensive interest. However, the organic transformations photocatalyzed by COFs under mild conditions remain a challenge. Herein, a boron-dipyrromethene (BODIPY) based 1D COF, namely JNM-12, was facilely constructed by Schiff-base condensation reaction. JNM-12 exhibited strong visible-light harvesting abilities and suitable photocatalysis energy potentials, enabling the activation of O2 to superoxide anions (O2 ⋅- ) and singlet oxygen (1 O2 ) under visible light irradiation. Benefiting from these properties, JNM-12 delivered excellent photocatalytic activity in the O2 ⋅- -mediated oxidative coupling of amines and 1 O2 -engaged aerobic oxidation of enamines. Our work paves a new way for synthesis of COFs as efficient, economical, and green photocatalysts for organic synthesis.

Reusable electrochemiluminescence biosensor based on tetrahedral DNA signal amplification for ultrasensitive detection of microRNAs.

A novel and reusable electrochemiluminescence biosensor was developed based on tetrahedral DNA (TDN) signal amplification for ultrasensitive detection of miRNA-27a. The flowered nickel-iron layered double hydroxide@AuNPs (NiFe-LDH@AuNPs) composites increase the amount of hairpin DNA fixed on the electrode. When miRNA is present, TDN-Ru(bpy)32+ acts as an ECL probe, forming a stable sandwich structure with miRNA-27a and hairpin DNA through base complementation pairing, thus achieving miRNA detection. This biosensor has the characteristics of high sensitivity, excellent selectivity, and good reproducibility.

High-entropy alloy nanopatterns by prescribed metallization of DNA origami templates.

High-entropy multimetallic nanopatterns with controlled morphology, composition and uniformity hold great potential for developing nanoelectronics, nanophotonics and catalysis. Nevertheless, the lack of general methods for patterning multiple metals poses a limit. Here, we develop a DNA origami-based metallization reaction system to prescribe multimetallic nanopatterns with peroxidase-like activities. We find that strong coordination between metal elements and DNA bases enables the accumulation of metal ions on protruding clustered DNA (pcDNA) that are prescribed on DNA origami. As a result of the condensation of pcDNA, these sites can serve as nucleation site for metal plating. We have synthesized multimetallic nanopatterns composed of up to five metal elements (Co, Pd, Pt, Ag and Ni), and obtained insights on elemental uniformity control at the nanoscale. This method provides an alternative pathway to construct a library of multimetallic nanopatterns.

Multiple Accessible Redox-Active Sites in a Robust Covalent Organic Framework for High-Performance Potassium Storage.

Covalent organic framework (COF) materials with porous character and robust structure have significant applied implications for K-ion battery (KIB) anodes, but they are limited by the low reversible capacity and inferior rate capability. Here, based on theoretical calculations, we identified that a porous bulk COF featuring numerous pyrazines and carbonyls in the π-conjugated periodic skeleton could provide multiple accessible redox-active sites for high-performance potassium storage. Its porous structure with a surface-dominated storage mechanism enabled the fast and stable storage of K-ions. Its insolubility in organic electrolytes and small volumetric change after potassiation ensured a robust electrode for stable cycling. As a KIB anode, this bulk COF demonstrated an unprecedentedly outstanding combination of reversible capacity (423 mAh g-1 at 0.1 C), rate capability (185 mAh g-1 at 10 C), and cyclability. The theoretical simulation and comprehensive characterizations confirmed the active sites are contributed by C═O, C═N, and the cation-π effect.

Dendrimer-like Hierarchical Framework Nucleic Acid for Real-Time Imaging of Intracellular Trafficking.

Framework nucleic acids (FNAs) represent a new type of DNA-based nanomaterials and possess great potentials in biosensing, bioimaging, and molecular delivery. Hierarchical DNA nanostructures that consist of multiple FNA monomers increase the capacity for drug delivery and multifunctional modification. However, there are relatively few studies devoted to the behavior and regulation of hierarchical FNAs in living cells, impeding their further applications. Herein, we constructed a dendritic nanostructure with five tetrahedral DNA nanocages and characterized the real-time internalization, inter-organelle trafficking, and exocytosis in living mammalian cells. In comparison to FNA monomers, FNA dendrimers exhibit increased endocytosis and prolonged cellular retention. Single-particle tracking on hundreds of FNA dendrimers exhibits no interference on the mobility or kinetics of subcellular organelles, implying that FNAs as well as their higher-order derivatives are ideal intracellular imaging probes and nanocarriers. Our study validates the suitability and superiority of hierarchical DNA nanostructures as high-valency scaffolds for biomedical applications.