Construction of Silver Clusters Capped by Zwitterionic Ethynide Ligands.

A zwitterionic ligand 3-(triethylammonio)propyne (TAP) has been employed to construct nine silver ethynide compounds for the first time. Single-crystal X-ray analyses reveal that compounds 1 and 2 are silver ethynide assemblies based on the Ag3 subunits and clusters 3-8 are small discrete clusters of Ag3, Ag6, Ag8, and Ag12, respectively, ligated by the bulky TAP ligand with different auxiliary ligands. In addition, upon acquiring the tripod-like tBuPO32-, a unprecedented 80 nuclei silver ethynide cluster was isolated and determined to be [(CF3CO2)5@Ag80(TAP)14(tBuPO3)16(CF3CO2)24]19+ by crystallography and thermogravimetric analysis. The C1 symmetry of Ag80 was deconstructed to be two [Ag40(TAP)7(tBuPO3)8(CF3CO2)12]12+ secondary building subunits arranged in a cross way, with five CF3CO2- trapped in the center. These results highlight that the elaborate selection of ethynide ligands is of great importance in the synthesis of novel silver ethynide clusters.

Silica coated upconversion nanoparticles: a versatile platform for the development of efficient theranostics.

Next generation theranostic devices will rely on the smart integration of different functional moieties into one system. These individual chemical elements will have a variety of desired chemical and physical properties and will need to behave in a multifunctional manner. Researchers have used upconversion nanoparticles (UCNPs) as a basis for superior imaging probes to locate cancerous lesions. The features of these nanoparticles, such as large anti-Stokes shifts, sharp emission bands, long-lived luminescence, and high resistance to photobleaching, have produced versatile probes. One way to improve these probes is to add a layer of dense or mesoporous silica to the outer surface of UCNPs (UCNP@SiO2). These modified UCNPs are chemically stable and much less cytotoxic than the original UCNPs. In addition, their surface can be easily modified to introduce various functional groups (e.g., -NH2, -COOH, -SH) via silanization, which facilitates conjugations with various biological molecules for multimodal imaging or synergetic therapeutics. This versatility makes UCNP@SiO2 particles excellent platforms for the construction of efficient theranostics. In this Account, we provide a comprehensive summary of recent progress in the development of UCNP@SiO2 nanocomposites for theranostics in the hope of speeding their translation into the clinic. We first discuss the major design principles and protocols for engineering various nanocomposites based on UCNP@SiO2 structures including those coated with dense silica, mesoporous silica, or hollow mesoporous silica. Next we summarize several representative efforts that probe the relaxivity mechanisms of these nanostructures as a way to optimize magnetic resonance sensitivity, multimode cancer imaging, near-infrared light-triggered chemotherapy, photodynamic therapy, and synergetic therapy (the combination of radiotherapy with chemotherapy, thermotherapy, or photodynamic therapy) using UCNP@SiO2-based theranostics. By rational integration of a wide range of features that convey multiple functions (such as imaging and therapy) into the structure or onto the surfaces of UCNP@SiO2, the constructed theranostics show promise for multimodal cancer imaging, biosensing, and effective cancer therapy. Finally, we discuss the limitations of UCNP@SiO2 nanostructures, the difficulties in the design of smart theranostics, and their potential role in clinical cancer research.

Left lower lobectomy and systematic lymph node dissection by complete video-assisted thoracic surgery.

A 50-year-old female was administered with left lower lobe lesion for 10 days. A preoperative chest computed tomography (CT) revealed a mass in the left basilar segment of the lung, about 2.1 cm × 1.7 cm in size. Therefore, video-assisted thoracic surgery (VATS) left lower lobectomy was performed. The operation takes 60 minutes. During the operation, the estimated blood loss was 15 mL. The patient was discharged on postoperative day (POD) 6 with no complications. And the pathological results confirmed the diagnosis of adenocarcinoma with no lymph nodes metastasis.

Construction of homogenous/heterogeneous hollow mesoporous silica nanostructures by silica-etching chemistry: principles, synthesis, and applications.

Colloidal hollow mesoporous silica nanoparticles (HMSNs) are aspecial type of silica-based nanomaterials with penetrating mesopore channels on their shells. HMSNs exhibit unique structural characteristics useful for diverse applications: Firstly, the hollow interiors can function as reservoirs for enhanced loading of guest molecules, or as nanoreactors for the growth of nanocrystals or for catalysis in confined spaces. Secondly, the mesoporous silica shell enables the free diffusion of guest molecules through the intact shell. Thirdly, the outer silica surface is ready for chemical modifications, typically via its abundant Si-OH bonds. As early as 2003, researchers developed a soft-templating methodto prepare hollow aluminosilicate spheres with penetrating mesopores in a cubic symmetry pattern on the shells. However, adapting this method for applications on the nanoscale, especially for biomedicine, has proved difficult because the soft templating micelles are very sensitive to liquid environments, making it difficult to tune key parameters such as dispersity, morphology and structure. In this Account, we present the most recent developments in the tailored construction of highly dispersive and monosized HMSNs using simple silica-etching chemistry, and we discuss these particles' excellent performance in diverse applications. We first introduce general principles of silica-etching chemistry for controlling the chemical composition and the structural parameters (particle size, pore size, etching modalities, yolk-shell nanostructures, etc.) of HMSNs. Secondly, we include recent progress in constructing heterogeneous, multifunctional, hollow mesoporous silica nanorattles via several methods for diverse applications. These elaborately designed HMSNs could be topologically transformed to prepare hollow mesoporous carbon nanoparticles or functionalized to produce HMSN-based composite nanomaterials. Especially in biomedicine, HMSNs are excellent as carriers to deliver either hydrophilic or hydrophobic anti-cancer drugs, to tumor cells, offering enhanced chemotherapeutic efficacy and diminished toxic side effects. Most recently, research has shown that loading one or more anticancer drugs into HMSNs can inhibit metastasis or reverse multidrug resistance of cancer cells. HMSNs could also deliver hydrophobic perfluorohexane (PFH) molecules to improve high intensity focused ultrasound (HIFU) cancer surgery by changing the tissue acoustic environment; and HMSNs could act as nanoreactors for enhanced catalytic activity and/or durability. The versatility of silica-etching chemistry, a simple but scalable synthetic methodology, offers great potential for the creation of new types of HMSN-based nanostructures in a range of applications.

Recent advances in hierarchically structured zeolites: synthesis and material performances.

Hierarchically structured zeolites (HSZs) have attracted increasing attention in the last few years, thanks to their unique hierarchical porous structures combining micro- and mesoporosity and superior material performances, especially in the bulky molecules-involved catalysis and adsorption applications. In this Feature Article, the recent advances in the HSZs synthetic methodologies and material performances in catalysis are overviewed. Further, some perspectives for the future development of HSZs are discussed.

Structural characteristics of oriented mesostructured silica thin films.

Mesoporous thin films synthesized via an electrochemical strategy (ref 1) generally show granular domains, each of which is composed of hexagonally packed one-dimensional channels oriented uniquely perpendicular to the film surface. Grain boundaries either parallel or normal to the channel direction might affect the properties and subsequent application of the film. In this study, the structural details of oriented mesostructured silica thin films have been examined by transmission electron microscope. The pore structures are characterized using the traditional crystallographic concepts but show different structural properties from that of polycrystalline materials. The boundary structures vary much depending on the residual internal stress and the orientation relationship between the bounded grains. A variety of structural features, typically near the large-angle tilt boundaries, have been observed including coincidence site lattices, lattice distortion, lattice displacement, and dislocations. According to the present structural analysis, microstructure evolution and potential applications have been discussed with respect to the oriented mesoporous films.

A highly efficient heterogeneous catalytic system for Heck reactions with a palladium colloid layer reduced in situ in the channel of mesoporous silica materials.

A new catalyst, Pd-SBA, was prepared by the introduction of an Si-H function into the channel of SBA-15 mesoporous materials resulting in a highly dispersed metal colloid layer on the pore walls of the support material, creating one of the most active heterogeneous catalysts for Heck coupling reactions.