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To understand the interaction mechanism between graphene oxide (GO) and typical phytopathogens, a particular investigation was conducted about the antimicrobial activity of GO against two bacterial pathogens (P. syringae and X. campestris pv. undulosa) and two fungal pathogens (F. graminearum and F. oxysporum). The results showed that GO had a powerful effect on the reproduction of all four pathogens (killed nearly 90% of the bacteria and repressed 80% macroconidia germination along with partial cell swelling and lysis at 500 μg mL(-1)). A mutual mechanism is proposed in this work that GO intertwinds the bacteria and fungal spores with a wide range of aggregated graphene oxide sheets, resulting in the local perturbation of their cell membrane and inducing the decrease of the bacterial membrane potential and the leakage of electrolytes of fungal spores. It is likely that GO interacts with the pathogens by mechanically wrapping and locally damaging the cell membrane and finally causing cell lysis, which may be one of the major toxicity actions of GO against phytopathogens. The antibacterial mode proposed in this study suggests that the GO may possess antibacterial activity against more multi-resistant bacterial and fungal phytopathogens, and provides useful information about the application of GO in resisting crop diseases.

We have demonstrated the design and synthesis of hyperbranched molecules that can be successfully imaged in vivo using (19)F MRI in under 10 min. These polymers are cytocompatible following chain extension with PEGMA. In addition, functionalization of these macromolecules can be achieved in a facile manner and with accessible and correct ligand presentation. Such hyperbranched polymers hold promise as new generation tracking and targeting MRI contrast agents.

Understanding the complex nature of diseased tissue in vivo requires development of more advanced nanomedicines, where synthesis of multifunctional polymers combines imaging multimodality with a biocompatible, tunable, and functional nanomaterial carrier. Here we describe the development of polymeric nanoparticles for multimodal imaging of disease states in vivo. The nanoparticle design utilizes the abundant functionality and tunable physicochemical properties of synthetically robust polymeric systems to facilitate targeted imaging of tumors in mice. For the first time, high-resolution (19)F/(1)H magnetic resonance imaging is combined with sensitive and versatile fluorescence imaging in a polymeric material for in vivo detection of tumors. We highlight how control over the chemistry during synthesis allows manipulation of nanoparticle size and function and can lead to very high targeting efficiency to B16 melanoma cells, both in vitro and in vivo. Importantly, the combination of imaging modalities within a polymeric nanoparticle provides information on the tumor mass across various size scales in vivo, from millimeters down to tens of micrometers.

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Memristors with history‐dependent resistance are considered as artificial synapses and have potential in mimicking the massive parallelism and low‐power operation existing in the human brain. However, the state‐of‐the‐art memristors still suffer from excessive write noise, abrupt resistance variation, inherent stochasticity, poor endurance behavior, and costly energy consumption, which impedes massive neural architecture. A robust and low‐energy consumption organic three‐terminal memristor based on ferroelectric polymer gate insulator is demonstrated here. The conductance of this memristor can be precisely manipulated to vary between more than 1000 intermediate states with the highest OFF/ON ratio of ≈104. The quasicontinuous resistive switching in the MoS2 channel results from the ferroelectric domain dynamics as confirmed unambiguously by the in situ real‐time correlation between dynamic resistive switching and polarization change. Typical synaptic plasticity such as long‐term potentiation and depression (LTP/D) and spike‐timing dependent plasticity (STDP) are successfully simulated. In addition, the device is expected to experience 1 × 109 synaptic spikes with an ultralow energy consumption for each synaptic operation (less than 1 fJ, compatible with a bio‐synaptic event), which highlights its immense potential for the massive neural architecture in bioinspired networks.

19 F magnetic resonance imaging (MRI) is a powerful noninvasive imaging technique with demonstrated potential for the detection of important diseases. The major challenge in the design of 19 F MRI agents is signal attenuation caused by the reduced solubility and segmental mobility of probes with high numbers of fluorine atoms. Careful choice of the fluorinated moiety is required to maintain image quality at the fluorine contents required for high imaging sensitivity. Here we report the synthesis of perfluoropolyether (PFPE) end-functionalized homopolymers of oligo(ethylene glycol) methyl ether acrylate (poly(OEGA) m -PFPE) as highly sensitive 19 F MRI contrast agents (CAs). The structural characteristics, conformation and aggregation behavior, 19 F NMR relaxation properties, and 19 F MR imaging were studied in detail. Dynamic light scattering and molecular dynamics (MD) simulations were conducted and demonstrated that poly(OEGA) m -PFPE with the longest poly(OEGA) m segments (m = 20) undergoes single-chain folding in water while poly(OEGA) 10 -PFPE and poly(OEGA) 4 -PFPE with shorter OEGA segments experience multiple-chain aggregation. Long 19 F T 2 relaxation times were measured for all poly(OEGA) m -PFPE polymers in PBS and in the presence of serum (>80 ms), and no obvious decrease in 19 F T 2 was observed with increasing fluorine content up to ∼30 wt %. Moreover, the signal-to-noise ratio increased linearly with increasing concentration of fluorine, indicating that the PFPE-based polymers can be applied as quantitative tracers. Furthermore, we investigated the in vivo behavior, in particular their biodistribution, of the polymers with different aggregation properties. Control over the balance of hydrophobicity and hydrophilicity allows manipulation of the aggregation state, and this leads to different circulation behavior in a murine model. This first report of the synthesis of polymeric PFPE-based 19 F MRI CAs demonstrates that these polymers are an exciting new class of 19 F MRI CAs with extremely high fluorine content and outstanding imaging sensitivity.