High purity of (7,5) SWNTs (approximately 79% of the semisonducting SWNT ensemble) can be obtained by polymer-assisted extraction from the narrow-diameter distributed SWNTs produced by the catalyst Co-MCM-41. The fluorene-based polymers are able to selectively wrap the single-walled carbon nanotubes (SWNTs) with certain chiral angles or diameters depending on their chemical structures. Poly(9,9-dioctyfluoreny1-2, 7-diyl) and poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(9,10-anthracene)] selectively wrap SWNTs with high chiral angles (>24.5 degrees). By contrast, poly[9,9-dioctylfluorenyl-2,7-diyl)-co-1,4-benzo-{2,1'-3}-thiadiazole)] preferentially wraps the SWNTs with certain diameter (1.02-1.06 nm).

Recently, two-dimensional transition metal dichalcogenides (TMDCs) have received tremendous attention in many fields including biomedicine. Herein, we develop a general method to dope different types of metal ions into WS2 nanoflakes, a typical class of TMDCs, and choose Gd(3+)-doped WS2 (WS2:Gd(3+)) with polyethylene glycol (PEG) modification as a multifunctional agent for imaging-guided combination cancer treatment. While WS2 with strong near-infrared (NIR) absorbance and X-ray attenuation ability enables contrasts in photoacoustic (PA) imaging and computed tomography (CT), Gd(3+) doping offers the nanostructure a paramagnetic property for magnetic resonance (MR) imaging. As revealed by trimodal PA/CT/MR imaging, WS2:Gd(3+)-PEG nanoflakes showed efficient tumor homing after intravenous injection. In vivo cancer treatment study further uncovered that WS2:Gd(3+)-PEG could not only convert NIR light into heat for photothermal therapy (PTT) but also enhance the ionizing irradiation-induced tumor damage to boost radiation therapy (RT). Owing to the improved tumor oxygenation after the mild PTT, the combination of PTT and RT induced by WS2:Gd(3+)-PEG resulted in a remarkable synergistic effect to destroy cancer. Our work highlights the promise of utilizing inherent physical properties of TMDC-based nanostructures, whose functions could be further enriched by elementary doping, for applications in multimodal bioimaging and synergistic cancer therapy.

Multifunctional nanoplatforms with special advantages in the diagnosis and treatment of cancer have been widely explored in nanomedicine. Herein, we synthesize two-dimensional core–shell nanocomposites (Ti3C2@Au) via a seed-growth method starting from the titanium carbide (Ti3C2) nanosheets, a classical type of MXene nanostructure. After growing gold on the surface of Ti3C2 nanosheets, the stability and biocompatibility of the nanocomposites are greatly improved by the thiol modification. Also importantly, the optical absorption in the near-infrared region is enhanced. Utilizing the ability of the high optical absorbance and strong X-ray attenuation, the synthesized Ti3C2@Au nanocomposites are used for photoacoustic and computed tomography dual-modal imaging. Importantly, the mild photothermal effect of the Ti3C2@Au nanocomposites could improve the tumor oxygenation, which significantly enhances the radiotherapy. No obvious long-term toxicity of the nanocomposites is found at the injected dose. This work highlights the promise of special properties of MXene-based multifunctional nanostructures for cancer theranostics.

A non-porous and amorphous fluoropolymer PFN with low dielectric constant of 2.33 and dielectric loss less than 1.2 × 10(-3) is reported here. PFN also exhibits good mechanical properties and high thermostability. This study is a new example of a fully dense material showing a low k value and having good thermo/mechanical properties.

Conspectus Redox active organic and polymeric materials have witnessed the rapid development and commercialization of lithium-ion batteries (LIBs) over the last century and the increasing interest in developing various alternatives to LIBs in the past 30 years. As a kind of potential alternative, organic and polymeric materials have the advantages of flexibility, tunable performance through molecular design, potentially high specific capacity, vast natural resources, and recyclability. However, until now, only a handful inorganic materials have been adopted as electrodes in commercialized LIBs. Although the development of carbonyl-based materials revived organic batteries and stimulated plentiful organic materials for batteries in the past 10 years due to their high theoretical capacities and long-term cycleabilities compared with their pioneers (e.g., conducting polymers), organic batteries are still facing many challenges. For example, it is still essential to enhance the theoretical and experimental capacities of organic materials. Moreover, typically, organic materials suffer relatively low conductivity, which limits their rate capability. In addition, many organic materials, especially small molecules, show poor cycling stability because of their dissolution in organic electrolytes. Other requirements, such as high voltage output and low cost, are also crucial for organic batteries. Therefore, insights into fundamentals (e.g., intramolecular and intermolecular interactions) for a deep understanding of organic batteries and constructive strategies ranging from material design to manipulation of other components (e.g., conductive additives, binders, electrolytes, and separators through controlling the intramolecular and intermolecular interactions and manipulating the ionic transport) are of great significance to boost the performance of organic batteries. In this Account, we give an overview of our efforts to develop high performance organic batteries with various strategies from the aspects of molecular design and the manipulation of other components. Inspired by the experience in organic electronics, we proposed that the extension of the π-conjugated system is helpful for stabilizing the +1/–1 charge/discharge states, improving the charge transport, and facilitating the layered packing (good for ionic diffusion) and hence would benefit the rate capability and cyclability. The π–d conjugation can effectively improve the electrical conductivity and provide stable and fast ionic storage, which enriches the materials for high-performance batteries and further deepens the understanding of conjugated coordination polymers (CCPs). Different from inorganic materials, organic materials are composed of molecules (either small molecules, macromolecules, or polymeric molecules) with weak intermolecular interactions. Therefore, the manipulation of active molecules or additives (conductive additives, binders, and other special additives) through control of intermolecular interactions is crucial for enhancing the electroc...

Abstract:Interbody fusion cages made of poly-ether-etherketone (PEEK) have been widely used in clinics for spinal disorders treatment; however, they do not integrate well with surrounding bone tissue. Ti-6Al-4V (Ti) has demonstrated greater osteoconductivity than PEEK, but the traditional Ti cage is generally limited by its much greater elastic modulus (110 GPa) than natural bone (0.05-30 GPa).In this study, we developed a porous Ti cage using electron beam melting (EBM) technique to reduce its elastic modulus and compared its spinal fusion efficacy with a PEEK cage in a preclinical sheep anterior cervical fusion model. A porous Ti cage possesses a fully interconnected porous structure (porosity: 68 ± 5.3%; pore size: 710 ± 42 μm) and a similar Young's modulus as natural bone (2.5 ± 0.2 GPa). When implanted in vivo, the porous Ti cage promoted fast bone ingrowth, achieving similar bone volume fraction at 6 months as the PEEK cage without autograft transplantation. Moreover, it promoted better osteointegration with higher degree (2-10x) of bone-material binding, demonstrated by histomorphometrical analysis, and significantly higher mechanical stability (P < 0.01), shown by biomechanical testing. The porous Ti cage fabricated by EBM could achieve fast bone ingrowth. In addition, it had better osseointegration and superior mechanical stability than the conventional PEEK cage, demonstrating great potential for clinical application.

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A novel functional oligomer (Si-TFVE) with a siloxane backbone and thermally cross-linkable trifluorovinyl ether groups (−OCFCF 2 ) is reported here. When postpolymerized at high temperature, Si-TFVE converts to an amorphous cross-linked network (Si-PFCB), which shows a dielectric constant of 2.33 and dielectric loss below 2.1 × 10 −3 at 30 MHz. Si-PFCB also shows excellent film uniformity with the surface roughness less than 5.79 nm over a 1 μm square area. Moreover, Si-PFCB shows high thermostability with a 5 wt % loss temperature of 472 °C and no obvious T g below 350 °C. In regard to the mechanical properties, Si-PFCB has Young's modulus, hardness, and bonding strength with silicon wafer surface of 10.06 GPa, 0.392, and 4.93 GPa, respectively. These results suggest that such oligomer is suitable for utilization in ultralarge scale integration circuits. In addition, this contribution provides a new route to prepare cross-linked organosiloxanes only by heating instead of using catalysts or initiators in the traditional procedures.