溶液自组装法构筑超分子杂化功能材料

以Anderson型多金属氧酸盐(POM)为构筑单元,通过共价键的方式将两个胆固醇分子连接到POM两端,制备了一种具有胆固醇-多金属氧酸盐-胆固醇结构的杂化分子,其在本体中通过自组装形成有序的六棱柱状结构。杂化分子的POM核在N,N-二甲基甲酰胺中具有良好的溶解性,而其胆固醇端基在甲苯中具有适当的溶解性。在甲苯体积分数为85.7%的条件下,杂化分子通过POM核与其胆固醇端基溶解性的差异、胆固醇端基之间较强的范德华力和POM核之间较强的相互静电作用力,可以自组装形成不同尺度的有序纤维结构,其相互缠绕最终形成典型的三维网状结构。在纤维结构中,杂化分子通过胆固醇层与POM层相互交替排列,在透射电镜表征中形成了明暗交替的层状精细结构。本研究工作在纳米材料的设计、组装和应用方面具有潜在的应用价值。     

Monodisperse Particles Based on Copolymers of Methyl methacrylate or Styrene with N-Vinylformamide

Sammary: Various techniques of one-step batch emulsion copolymerization of methyl methacrylate (MMA) or styrene (St) with N-vinylformamide (NVF) initiated by 2,2′-azobis(2-methylpropanamidine) (AIBA) or 2,2′-azobis[4,5-dihydroimidazol-2-yl] (AIP) dihydrochlorides in the presence of dextran, cetyltrimethylammonium bromide (CTAB) or without any stabilizers were examined to obtain monodisperse submicron and nano- particles, having both positive surface charge and hydrophilic surface. After hydrolysis in acidic media, the particle surface contained amino groups originating from NVF units along with carboxylic groups from hydrolyzed initiator residues. The obtained particles were tested as building blocks of hierarchic structures. Owing to their amphiphilic surface, the particles were capable of self-assembling from their dispersions into three-dimentional (3D) ordered arrays.     

含Janus粒子组装体的构筑、调控及功能的模拟与理论分析

Janus粒子由于其表面性质与形状特征的不对称性而展现出独特的力学、光学、电学、磁学和表面两亲性能,在构筑复杂组装结构及设计新型功能材料方面有着广阔的应用前景.本文主要从计算机模拟与理论分析的角度,结合相关实验体系,系统地总结了目前对含Janus粒子组装体的体系构筑、结构调控及材料功能等的相关研究进展.从Janus粒子自组装结构的精确构筑与动态响应性、界面结构的熵驱调控、非平衡组装动力学及含Janus粒子组装体功能的模拟与预报等4个方面,详细阐述了Janus粒子的复杂多级组装结构及其背后蕴含的热力学与动力学的机理,并介绍了一系列基于含Janus粒子组装体的聚合物基复合材料独特的功能及其潜在应用.在此基础上,指出合理设计Janus粒子的非对称性质以及巧妙调控组装体内的熵、焓平衡,是控制其多级组装结构,进而开发相应新型功能材料的关键,并对Janus粒子未来的理论和模拟研究趋势进行了展望.     

An Ultrasound Activated Vesicle of Janus Au‐MnO Nanoparticles for Promoted Tumor Penetration and Sono‐Chemodynamic Therapy of Orthotopic Liver Cancer

Sonodynamic therapy (SDT) has the advantages of high penetration, non‐invasiveness, and controllability, and it is suitable for deep‐seated tumors. However, there is still a lack of effective sonosensitizers with high sensitivity, safety, and penetration. Now, ultrasound (US) and glutathione (GSH) dual responsive vesicles of Janus Au‐MnO nanoparticles (JNPs) were coated with PEG and a ROS‐sensitive polymer. Upon US irradiation, the vesicles were disassembled into small Janus Au‐MnO nanoparticles (NPs) with promoted penetration ability. Subsequently, GSH‐triggered MnO degradation simultaneously released smaller Au NPs as numerous cavitation nucleation sites and Mn²⁺ for chemodynamic therapy (CDT), resulting in enhanced reactive oxygen species (ROS) generation. This also allowed dual‐modality photoacoustic imaging in the second near‐infrared (NIR) window and T₁‐MR imaging due to the released Mn²⁺, and inhibited orthotopic liver tumor growth via synergistic SDT/CDT.     

Synthesis of Monodisperse Bi‐Compartmentalized Amphiphilic Janus Microparticles for Tailored Assembly at the Oil–Water Interface

Janus particles endowed with controlled anisotropies represent promising building blocks and assembly materials because of their asymmetric functionalities. Herein, we show that using the seeded monomer swelling and polymerization technique allows us to obtain bi‐compartmentalized Janus microparticles that are generated depending on the phase miscibility of the poly (alkyl acrylate) chains against the polystyrene seed, thus minimizing the interfacial free energy. When tetradecyl acrylate is used, complete compartmentalization into two distinct bulbs can be achieved, while tuning the relative dimension ratio of compartmented bulb against the whole particle. Finally, we have demonstrated that selectively patching the silica nanoparticles onto one of the bulb surfaces gives amphiphilicity to the particles that can assemble at the oil–water interface with a designated level of adhesion, thus leading to development of a highly stable Pickering emulsion system.     

Reversible Phase Transition of Robust Luminescent Hybrid Hydrogels

We report herein on remote control over a reversible phase transition of robust luminescent hybrid hydrogels as enabled by the rational selection and incorporation of photoswitches. Azobenzene units functionalized with a guanidinium group were utilized as the photoswitches and incorporated through a host–guest inclusion method involving α‐cyclodextrins functionalized with 2,6‐pyridinedicarboxylic acid (PDA) groups. While the guanidinium functional groups bind to the negatively charged Laponite matrix surface to connect organic and inorganic components, the PDA groups enable simultaneous coordination with different lanthanide metal ions, thus rendering the hydrogel broadly luminescent. Owing to its conformation‐dependent binding behavior with α‐cyclodextrin, the isomerization of azobenzene induced association or dissociation of the inclusion complexes and thus lead to a reversible photocontrolled sol?gel phase transition of the luminescent hybrid hydrogels.     

Janus超支化超分子聚合物的构筑及电化学响应性自组装行为研究

本工作报道了第一例具有电化学氧化还原刺激响应性的Janus超支化超分子聚合物,研究了其自组装及响应性解组装的行为.通过阴离子开环聚合和阳离子开环聚合的方法,分别合成了以β-环糊精为中心的亲水超支化聚缩水甘油醚CD-g-HPG和末端为二茂铁的疏水超支化聚(3-乙基-3-羟甲基环氧丁烷)Fc-g-HBPO.两者通过Fc/CD之间的主客体包结络合作用,构筑了两亲性Janus超支化超分子聚合物HBPO-b-HPG.该聚合物在水中可以自组装形成囊泡.通过动态光散射(DLS)跟踪、2D-NOESY和循环伏安曲线表征了CD-g-HPG和Fc-g-HBPO之间的主客体包结络合作用,通过扫描电子显微镜(SEM)和透射电子显微镜(TEM)表征了囊泡结构.最后,研究了囊泡在电化学刺激下的解组装行为,同时也验证了囊泡在加热、加入主客体竞争分子和化学氧化下的稳定性.     

A Rapid Self-Assembly Peptide Hydrogel for Recruitment and Activation of Immune Cells

Self-assembly peptide nanotechnology has attracted much attention due to its regular and orderly structure and diverse functions. Most of the existing self-assembly peptides can form aggregates with specific structures only under specific conditions and their assembly time is relatively long. They have good biocompatibility but no immunogenicity. To optimize it, a self-assembly peptide named DRF3 was designed. It contains a hydrophilic and hydrophobic surface, using two N-terminal arginines, leucine, and two c-terminal aspartate and glutamic acid. Meanwhile, the c-terminal of the peptide was amidated, so that peptide segments were interconnected to increase diversity. Its characterization, biocompatibility, controlled release effect on antigen, immune cell recruitment ability, and antitumor properties were examined here. Congo red/aniline blue staining revealed that peptide hydrogel DRF3 could be immediately gelled in PBS. The stable β-sheet secondary structure of DRF3 was confirmed by circular dichroism spectrum and IR spectra. The observation results of cryo-scanning electron microscopy, transmission electron microscopy, and atomic force microscopy demonstrated that DRF3 formed nanotubule-like and vesicular structures in PBS, and these structures interlaced with each other to form ordered three-dimensional nanofiber structures. Meanwhile, DRF3 showed excellent biocompatibility, could sustainably and slowly release antigens, recruit dendritic cells and promote the maturation of dendritic cells (DCs) in vitro. In addition, DRF3 has a strong inhibitory effect on clear renal cell carcinoma (786-0). These results provide a reliable basis for the application of peptide hydrogels in biomedical and preclinical trials.     

Direct Conversion of Bulk Metals to Size‐Tailored,Monodisperse Spherical Non‐Coinage‐Metal Nanocrystals

Monodisperse non‐noble metal nanocrystals (NCs) that are highly uniform in shapes and particle size are much desired in various advanced applications, and are commonly prepared by either thermal decomposition or reduction, where reactive organometallic precursors or/and strong reducing agents are mandatory; however, these are usually toxic, costly, or suffer a lack of availability. Bulk Group 12 metals can now be converted into ligand‐protected, highly crystalline, monodisperse spherical metal NCs with precisely controlled sizes without using any precursors and reducers. The method is based on low‐power NIR‐laser‐induced size‐selective layer‐by‐layer surface vaporization. The monodisperse Cd NCs show pronounced deep‐UV (DUV) localized surface plasmon resonance making them highly competitive DUV‐plasmonic materials. This approach will promote appreciably the emergence of a wide range of monodisperse technically important non‐coinage metal NCs with compelling functionalities.     

Hybrid Chelator-Based PSMA Radiopharmaceuticals: Translational Approach

(1) Background: Prostate-specific membrane antigen (PSMA) has been extensively studied in the last decade. It became a promising biological target in the diagnosis and therapy of PSMA-expressing cancer diseases. Although there are several radiolabeled PSMA inhibitors available, the search for new compounds with improved pharmacokinetic properties and simplified synthesis is still ongoing. In this study, we developed PSMA ligands with two different hybrid chelators and a modified linker. Both compounds have displayed a promising pharmacokinetic profile. (2) Methods: DATA^5m.SA.KuE and AAZTA⁵.SA.KuE were synthesized. DATA^5m.SA.KuE was labeled with gallium-68 and radiochemical yields of various amounts of precursor at different temperatures were determined. Complex stability in phosphate-buffered saline (PBS) and human serum (HS) was examined at 37 °C. Binding affinity and internalization ratio were determined in in vitro assays using PSMA-positive LNCaP cells. Tumor accumulation and biodistribution were evaluated in vivo and ex vivo using an LNCaP Balb/c nude mouse model. All experiments were conducted with PSMA-11 as reference. (3) Results: DATA^5m.SA.KuE was synthesized successfully. AAZTA⁵.SA.KuE was synthesized and labeled according to the literature. Radiolabeling of DATA^5m.SA.KuE with gallium-68 was performed in ammonium acetate buffer (1 M, pH 5.5). High radiochemical yields (>98%) were obtained with 5 nmol at 70 °C, 15 nmol at 50 °C, and 60 nmol (50 µg) at room temperature. [⁶⁸Ga]Ga-DATA^5m.SA.KuE was stable in human serum as well as in PBS after 120 min. PSMA binding affinities of AAZTA⁵.SA.KuE and DATA^5m.SA.KuE were in the nanomolar range. PSMA-specific internalization ratio was comparable to PSMA-11. In vivo and ex vivo studies of [¹⁷⁷Lu]Lu-AAZTA⁵.SA.KuE, [⁴⁴Sc]Sc-AAZTA⁵.SA.KuE and [⁶⁸Ga]Ga-DATA^5m.SA.KuE displayed specific accumulation in the tumor along with fast clearance and reduced off-target uptake. (4) Conclusions: Both KuE-conjugates showed promising properties especially in vivo allowing for translational theranostic use.     

Electrospun Aspirin/Eudragit/Lipid Hybrid Nanofibers for Colon-targeted Delivery Using an Energy-saving Process

Both electrospinning apparatus and their commercial pro-ducts are extending their applications in a wide variety of fields. However, very limited reports can be found about how to implement an energy-saving process and in turn to reduce the production cost. In this paper, a brand-new type of coaxial spinneret with a solid core and its electrospinning methods are developed. A novel sort of medicated Eudragit/lipid hybrid nanofibers are gene-rated for providing a colon-targeted sustained release of aspirin. A series of characterizations demonstrates that the as-prepared hybrid nanofibers have a fine linear morphology with the aspirin/lipid separated from the matrix Eudragit to form many tiny islands. In vitro dissolution tests exhibit that the hybrid nanofibers are able to effectively prevent the release of aspirin under an acid condition (8.7%±3.4% for the first two hours), whereas prolong the drug release time period under a neutral condition(99.7±4.2% at the se-venth hour). The energy-saving mechanism is discussed in detail. The prepared aspirin-loaded hybrid nanofibers can be further transferred into an oral dosage form for potential application in counte-ring COVID-19 in the future.     

Supramolecular Copolymerization as a Strategy to Control the Stability of Self‐Assembled Nanofibers

A major challenge in supramolecular polymerization is controlling the stability of the polymers formed, that is, controlling the rate of monomer exchange in the equilibrium between monomer and polymer. The exchange dynamics of supramolecular polymers based on benzene‐1,3,5‐tricarboxamide (BTA) can be regulated by copolymerizing molecules with dendronized (dBTA) and linear (nBTA) ethylene glycol‐based water‐soluble side chains. Whereas nBTAs form long nanofibers in water, dBTAs do not polymerize, forming instead small spherical aggregates. The copolymerization of the two BTAs results in long nanofibers. The exchange dynamics of both the BTA monomers in the copolymer are significantly slowed down in the mixed systems, leading to a more stable copolymer, while the morphology and spectroscopic signature of the copolymers are identical to that of nBTA homopolymer. This copolymerization is the supramolecular counterpart of styrene/ maleic anhydride copolymerization.     

Emergent Self-Assembly Pathways to Multidimensional Hierarchical Assemblies using a Hetero-Seeding Approach

The controlled formation of complex and functional 1-, 2-, and 3D hierarchical assemblies from molecular building blocks represents a key current challenge. Herein, we report the use of a seeded growth approach for a series of perylenediimide-based molecules (PDIs 1 – 4 ) to access otherwise inaccessible self-assembly pathways that yield complex hierarchical structures. The key to the new approach is to use hetero-seeds which possess a different composition and morphology from that of the molecular building block. For example, a nanotube seed (from PDI 3 ) and a microribbon seed (from PDI 4 ) were found to initiate different self-assembly pathways for PDI 1 , which normally assembles to yield nanocoils. This led to the formation of unprecedented 3D scroll-like and scarf-like hierarchical nanostructures, respectively. Also, the hetero-seeds from PDI 3 initiate hidden self-assembly pathways of PDI 2 to generate 1D tubular heterojunctions. Significantly, this new strategy offers new opportunities to create emergent and functional hierarchical and complex structures from small molecule precursors.     

一种制备单分散SiO2空心微球的新方法

在乙醇/氨水介质中, 分别以分散聚合和无皂乳液聚合方法制得的不同粒径聚苯乙烯(PS)微球为模板, 以正硅酸乙酯(TEOS)为前驱体, 通过控制介质中氨水的初始体积, 一步法制得了不同粒径的单分散SiO2空心微球. 整个过程无需添加其它溶剂溶解或高温煅烧的方法来除去模板微球. 对SiO2空心微球进行测试表征, 提出了SiO2空心微球的可能形成机制.     

A Robust Photocatalytic Hybrid Material Composed of Metal-Organic Cages and TiO2 for Efficient Visible-Light-Driven Hydrogen Evolution

The design of photochemical molecular devices (PMDs) for photocatalytic H₂ production from water is a meaningful but challenging subject currently. Herein, a Pd₂L₄ type metal-organic cage (denoted as MOC-Q2) is designed as a PMD, which consists of two catalytic centers (Pd²⁺) and four photosensitive ligands (L-2) with four pyridine anchoring groups. Subsequently, the MOC-Q2 is combined with TiO₂ to form TiO₂-MOC-Q2 hybrid materials with different MOC-Q2 contents by a facile sol-gel method, which have micro/mesoporous structures and large surface areas. The optimized TiO₂-MOC-Q2 (6.5 wt%) exhibits high H₂ production activity (7.9 mmol g⁻¹ h⁻¹ within 5 h) and excellent durability, giving a TON value of 23477 or 11739 (based on MOC-Q2 or Pd moles) after recycling for 7 rounds. By contrast, the pure MOC-Q2 only shows an ordinary photocatalytic H₂ production rate (0.84 mmol g⁻¹ h⁻¹ within 5 h) in the homogeneous system. It can be deduced that TiO₂ drives the photocatalysis and simultaneously acts as the structure promoter. This study presents a meaningful and distinctive attempt of a new approach for the design and development of MOC-based heterogeneous photocatalysts.     

大分子体系的量子化学分块方法

碎片化方法为量子化学方法的发展以及在大分子体系的应用开辟了新的道路。在过去的十年里,我们见证了该领域的诸多成果,并且我们相信该方法的发展仍将持续下去。这篇文章简单回顾了近期碎片化方法在大分子电子结构计算领域的进展,重点突出中国学者在该领域的贡献。     

A study of the catalytic behavior of phosphotungstic acid-modified Janus particles in a heterogeneous oil/water pickering emulsion system

An emulsion interface materialization method was used to obtain amphiphilic silica Janus nanoparticles. Reducing the photosynthesis of aquatic organisms after water pollution. PW₁₂O₄₀³⁻ was introduced onto Janus particles by ion exchange, and an amphiphilic particle emulsion catalyst (PWO-J) was prepared. Hydrogen peroxide was used as the oxygen source, and the amphiphilicty of the catalyst was used to assemble the catalyst at the Pickering emulsion interface. The PWO-J catalyst was found to exhibit very high catalytic activity toward the oxidation of oleic acid in water-in-oil systems. The results showed that PWO-J catalysis of oxidation had similar results as CTAB and phosphotungstic acid (control system) under the same conditions. The azelaic acid recovery rate was 86.7%, and PWO-J could be reused 4 times. A reaction mechanism was proposed, and the constructed model was used to calculate a reaction rate constant of 15.32 × 10⁻⁵L•mol⁻¹•s⁻¹ for the PWO-J system. The PWO-J system had a lower activation energy than the control system, showing that the catalytic oxidation of oleic acid into azelaic acid was more likely to occur in the PWO-J system.     

Surface‐Confined Self‐Assembled Janus Tectons: A Versatile Platform towards the Noncovalent Functionalization of Graphene

A general strategy for simultaneously generating surface‐based supramolecular architectures on flat sp²‐hybridized carbon supports and independently exposing on demand off‐plane functionality with controlled lateral order is highly desirable for the noncovalent functionalization of graphene. Here, we address this issue by providing a versatile molecular platform based on a library of new 3D Janus tectons that form surface‐confined supramolecular adlayers in which it is possible to simultaneously steer the 2D self‐assembly on flat C(sp²)‐based substrates and tailor the external interface above the substrate by exposure to a wide variety of small terminal chemical groups and functional moieties. This approach is validated throughout by scanning tunneling microscopy (STM) at the liquid–solid interface and molecular mechanics modeling studies. The successful self‐assembly on graphene, together with the possibility to transfer the graphene monolayer onto various substrates, should considerably extend the application of our functionalization strategy.     

A Surfactant‐Free and Shape‐Controlled Synthesis of Nonspherical Janus Particles with Thermally Tunable Amphiphilicity

A surfactant‐free approach is proposed to synthesize nonspherical Janus particles with temperature‐dependent wettability on hydrophobic surfaces. Sub‐micrometer‐sized particles comprising poly(styrene‐co‐divinylbenzene) core and a thermally responsive poly(N‐isopropylacrylamide‐co‐methacrylic acid) shell are first synthesized to stabilize styrene droplets in water, producing a Pickering emulsion. Upon heating to 80 °C and subsequent addition of initiators to the aqueous phase, styrene droplets are polymerized and combine with the core–shell particles to construct dumbbell‐shaped nonspherical particles. The shape of the nonspherical particles is controllable by adjusting the equilibrium time of the Pickering emulsion at 80 °C, which is conducted prior to polymerization. The mechanism of formation is discussed in more detail. Since molecular surfactants or stabilizers are not used during the synthesis, the present nonspherical particles well exhibit their own temperature‐dependent amphiphilic characteristics. The aqueous dispersion containing the dumbbell‐shaped particles alters its wettability on hydrophobic polymer surfaces according to temperature changes, demonstrating its temperature‐dependent amphiphilicity change.

     

Towards a universal organogelator:A general mixing approach to fabricate various organic compounds into organogels

Low-molecular-weight organogels(LMOG) have been attracting a surge interest in fabricating soft materials.Although the finding of the gelator molecules has been developed from serendipity to objective design,the achievement of the gelator molecules still needs good design and tedious organic synthesis.In this paper,we proposed a simple and general mixing approach to get the organogel for nearly all the organic compounds and even soluble nanoparticles without any modification.We have designed a universal gel...