The applications of fluorinated molecules in bioengineering and nanotechnology are expanding rapidly with the controlled introduction of fluorine being broadly studied due to the unique properties of ...C–F bonds. This review will focus on the design and utility of C–F containing materials in imaging, therapeutics, and environmental applications with a central theme being the importance of controlling fluorine–fluorine interactions and understanding how such interactions impact biological behavior. Low natural abundance of fluorine is shown to provide sensitivity and background advantages for imaging and detection of a variety of diseases with 19F magnetic resonance imaging, 18F positron emission tomography and ultrasound discussed as illustrative examples. The presence of C–F bonds can also be used to tailor membrane permeability and pharmacokinetic properties of drugs and delivery agents for enhanced cell uptake and therapeutics. A key message of this review is that while the promise of C–F containing materials is significant, a subset of highly fluorinated compounds such as per- and polyfluoroalkyl substances (PFAS), have been identified as posing a potential risk to human health. The unique properties of the C–F bond and the significant potential for fluorine–fluorine interactions in PFAS structures necessitate the development of new strategies for facile and efficient environmental removal and remediation. Recent progress in the development of fluorine-containing compounds as molecular imaging and therapeutic agents will be reviewed and their design features contrasted with environmental and health risks for PFAS systems. Finally, present challenges and future directions in the exploitation of the biological aspects of fluorinated systems will be described.
Rechargeable batteries paired with sodium metal anodes are considered to be one of the most promising high-energy and low-cost energy-storage systems. However, the use of highly reactive sodium metal ...and the formation of sodium dendrites during battery operation have caused safety concerns, especially when highly flammable liquid electrolytes are used. Here we design and develop solvent-free solid polymer electrolytes (SPEs) based on a perfluoropolyether-terminated polyethylene oxide (PEO)-based block copolymer for safe and stable all-solid-state sodium metal batteries. Compared with traditional PEO SPEs, our results suggest that block copolymer design allows for the formation of self-assembled nanostructures leading to high storage modulus at elevated temperatures with the PEO domains providing transport channels even at high salt concentration (ethylene oxide/sodium = 8/2). Moreover, it is demonstrated that the incorporation of perfluoropolyether segments enhances the Na+ transference number of the electrolyte to 0.46 at 80 °C and enables a stable solid electrolyte interface. The new SPE exhibits highly stable symmetric cell-cycling performance at high current density (0.5 mA cm−2 and 1.0 mAh cm−2, up to 1,000 h). Finally, the assembled all-solid-state sodium metal batteries demonstrate outstanding capacity retention, long-term charge/discharge stability (Coulombic efficiency, 99.91%; >900 cycles with Na3V2(PO4)3 cathode) and good capability with high loading NaFePO4 cathode (>1 mAh cm−2).Rechargeable batteries with sodium metal anodes are promising as energy-storage systems despite safety concerns related to reactivity and dendrite formation. Solvent-free perfluoropolyether-based electrolytes are now reported for safe and stable all-solid-state sodium metal batteries.
The convenience of injectable hydrogels that can provide high loading of diverse phototherapy agents and further long‐time retention at the tumor site has attracted tremendous interest in ...simultaneous photothermal and photodynamic cancer therapies. However, to incorporate the phototherapy agents into hydrogels, complex modifications are generally unavoidable. Moreover, these phototherapy agents usually suffer from low efficiency and work at different irradiation wavelengths outside the near infrared windows. Hence, a method for the fabrication of an injectable hydrogel for simultaneous photothermal therapy and photodynamic therapy, through the Schiff‐base reaction between amido modified carbon dots (NCDs) and aldehyde modified cellulose nanocrystals is proposed. The NCDs act as both phototherapy agents and crosslinkers to form hydrogels. Significantly, the NCDs demonstrate an extremely high photothermal conversion efficiency of 77.6% which is among the highest levels for photothermal agents and a high singlet quantum yield of 0.37 under a single 660 nm light‐emitting diode irradiation. The hydrogels are examined through in vitro and in vivo animal experiments which show nontoxic and effectively tumor inhibition. Thus, the strategy of direct reaction of phototherapy agents and the matrix not only provides new strategies for injectable hydrogel fabrication but paves a new road for advanced tumor treatment.
A novel strategy is developed for the fabrication of injectable hydrogels with extremely high efficiency in simultaneous photothermal therapy and photodynamic therapy, through a simple Schiff base reaction between carbon dots decorated with amido groups and aldehyde modified cellulose nanocrystals, which not only provides a new strategy for injectable hydrogel fabrication but paves a new road for advanced tumor treatment.
Sodium-ion batteries are promising alternative electrochemical energy storage devices due to the abundance of sodium resources. One of the challenges currently hindering the development of the ...sodium-ion battery technology is the lack of electrode materials suitable for reversibly storing/releasing sodium ions for a sufficiently long lifetime. Redox-active polymers provide opportunities for developing advanced electrode materials for sodium-ion batteries because of their structural diversity and flexibility, surface functionalities and tenability, and low cost. This review provides a short yet concise summary of recent developments in polymer electrode materials for sodium-ion batteries. Challenges facing polymer electrode materials for sodium-ion batteries are identified and analyzed. Strategies for improving polymer electrochemical performance are discussed. Future research perspectives in this important field are projected.
•Linear and nonlinear SSSI analyses of buildings using SASSI and LS-DYNA.•Subjectively compared results with observations from centrifuge experiments.•Simulations and experiments predict minimal SSSI ...effects in global response.•However, adjacent restraint can effect nonlinear footing response considerably.
The influence of structure-soil-structure interaction (SSSI) in low- to medium-rise buildings is investigated through numerical simulations, and observations are compared with those from previous studies that analyzed data from a set of centrifuge experiments of similar models. The buildings include a one-story moment-resisting frame building on spread footings and a two-story shear wall building on a basemat. The numerical simulations are performed using the industry-standard, frequency-domain, linear analysis code SASSI, and the time-domain nonlinear finite-element analysis code, LS-DYNA. In LS-DYNA the simulations are performed with and without geometric nonlinearities (gapping, sliding and uplift) to understand their effects on SSSI. Three plan arrangements of the buildings are considered to characterize the influence of relative location on SSSI: (1) an in-plane SSSI (iSSSI) arrangement, in which the two buildings are placed adjacent to each other along a line parallel to the direction of ground shaking, (2) an anti-plane arrangement (aSSSI), in which the two buildings are placed adjacent to each other along a line perpendicular to the direction of ground shaking, and (3) a combined in-plane-anti-plane (cSSSI) arrangement, in which two shear wall buildings are placed at two adjacent sides of the frame building on footings. Results from the numerical simulations in SASSI and LS-DYNA show that SSSI has negligible effect on the global spectral accelerations of the buildings in these arrangements. The numerical simulations agree with experimental observations in this regard. Numerical investigations into the SSSI response of the frame building on footings placed adjacent to a deep basement show that the presence of the deep basement reduces uplift in the footings and results in smaller peak spectral accelerations at the roof, underscoring the potential importance of geometric nonlinearities (gapping, sliding and uplift) in SSSI and foundation design.
Fluorine-containing polymeric materials are receiving increasing attention as imaging probes in fluorine-19 magnetic resonance imaging (19F MRI), for example to enable quantitative in vivo detection ...of cells. Here we describe the one-pot polymerization synthesis of 19F-containing functional poly(oligo(ethylene glycol) methyl ether methacrylate-co-2,2,2-trifluoroethyl acrylate-b-poly(styrene-co-3-vinylbenzaldehyde) (poly(OEGA-co-TFEA)-b-poly(St-co-VBA)) copolymers as a new class of fluorinated MRI agent. A range of nanoparticle morphologies, including spheres, worm-like particles, and vesicles were formed as a consequence of polymerization-induced self-assembly (PISA). It was found that the extent of cell uptake strongly depends on the morphology of the nano-objects, with preferable uptake for worm-like particles compared to spherical nanoparticles and vesicles. All the nano-objects have a single resonance in the 19F NMR spectrum with relatively short MRI relaxation times, which were independent of the morphology of the nano-objects. These results confirm that these polymeric nano-objects of varied morphologies are promising as 19F MRI imaging agents for use in tracking of cells and selective MRI.
Studying the interactions between nanoengineered materials and biological systems plays a vital role in the development of biological applications of nanotechnology and the improvement of our ...fundamental understanding of the bio-nano interface. A significant barrier to progress in this multidisciplinary area is the variability of published literature with regards to characterizations performed and experimental details reported. Here, we suggest a 'minimum information standard' for experimental literature investigating bio-nano interactions. This standard consists of specific components to be reported, divided into three categories: material characterization, biological characterization and details of experimental protocols. Our intention is for these proposed standards to improve reproducibility, increase quantitative comparisons of bio-nano materials, and facilitate meta analyses and in silico modelling.
High‐capacity lithium‐ion battery anode materials, such as transition metal oxides, Sn and Si, suffer from large volume expansion during lithiation, which causes capacity decay. Introducing ...sufficient void space to accommodate the volume change is essential to achieve prolonged cycling stability. However, excessive void space may significantly compromise the volumetric energy density. Herein, a method to control the void size in iron oxide@carbon (FeOx@C) yolk–shell structures is developed and the relationship between the void space and electrochemical performance is demonstrated. With an optimized void size, the FeOx@C yolk–shell structure exhibits the best cycling performance. A high reversible capacity of ≈810 mA h g−1 is obtained at 0.2 C, maintaining 790 mA h g−1 after 100 cycles. This contrasts with FeOx@C materials having either smaller or larger void sizes, in which significant capacity fading is observed during cycling. This contribution provides an effective approach to alleviate the volume expansion problem, which can be generally applied to other anode materials to improve their performance in LIBs.
Iron oxide@carbon yolk–shell structures with tunable void space are prepared and applied as anode materials for lithium ion batteries. The relationship between the size of void and the electrochemical performance is systematically studied. The results show that with an optimized void size, the iron oxide@carbon yolk–shell structure exhibits the best cycling stability.
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