Volume 11 Issue 10, October 2012

Nanoparticle-enabled, sustained delivery of soluble hydrophilic cytokines and hydrophobic inhibitors engages the innate and adaptive immune systems to fight cancer.

A powerful new set of tools combining artificial synthesis and in situ characterization of correlated oxides unites the processes of materials discovery and understanding, and reveals the origin of a dimensionality-induced metal–insulator transition.

The role of dispersion forces in molecule–metal bonding has often been underestimated or ignored. Two groups now report independent single-molecule experiments that illustrate and quantify the effect of such interactions on bonding strength.

In semiconducting polymers, the mobility of negative charges is typically much smaller than that of positive charges. Identification of a universal electron-trap level that is associated with water complexation now clarifies this difference and provides guidelines for the design of improved organic semiconductors.

Dislocation motion is crucial to the deformation of materials. The discovery that at least at lower temperatures quantum effects play an important role in this process considerably improves quantitative predictions of mechanical properties.

Real-time transmission electron microscopy shows that the formation of crystal nuclei of organic molecules in solution occurs inside dense liquid nanoclusters.

A polymeric tissue-engineered structure capable of swimming in a similar manner to a jellyfish is created by mimicking the structural design, stroke kinematics and fluid dynamics of the organism.

Upconversion nanoparticles that convert low-energy light into high-energy light hold promise for boosting solar-cell efficiency and enabling highly sensitive biological assays. But their spectral conversion under broadband excitation has been challenging, until now.

The motion of dislocations under stress is a key process in crystal plasticity. The finding that at low temperatures differences between experiments and theoretical predictions of dislocation activation can be explained by quantum effects arising from crystal zero-point vibrations represents a significant advance in our understanding of plasticity.

The dynamics of spins in single atomic layers of cuprates and other compounds are important for understanding their properties, such as magnetism and high-temperature superconductivity. Now, spin excitations in isolated single layers of a cuprate have been measured, providing valuable feedback on their magnetic properties.

The electronic interactions at the interface of oxide materials promise properties that can be very different from those of the parent compounds. The finding that many-body interactions in oxide superlattices can be used to engineer electronic properties offers a new strategy for designing oxide heterostructures.

Memristors are devices whose dynamic properties are of interest because they can mimic the operation of biological synapses. The demonstration that ferroelectric domains in tunnel junctions behave like memristors suggests new approaches for designing neuromorphic circuits.

Its high carrier mobility is one of the factors that makes graphene interesting for electronic and photonic applications at terahertz frequencies. Such possibilities are now further supported by the demonstration of an efficient room-temperature graphene detector for terahertz radiation that promises to be considerably faster than competing techniques.

Van der Waals interactions are critical to the understanding of functional metal/molecule interfaces in catalysis, molecular electronics and self-assembly. Such interactions have now been characterized at the single-molecule level through a combination of measurements of the stretching mechanics of molecular junctions and atomistic simulations.

Mechanistic details on how a molecular crystal nucleates on a surface remain limited because it is difficult to probe rare events at the molecular scale. Now, single-molecule real-time transmission electron microscopy shows that a single-molecule template on the surface of carbon nanohorns can nucleate the crystallization of two organic compounds, and that the mechanism is reminiscent of a two-step nucleation process in solution.

Electron transport in semiconducting polymers is usually inferior to hole transport, which is ascribed to charge trapping on defect sites. The observation of an identical electron-trap distribution in a range of materials now points to a common origin of these states that, as calculations suggest, may be related to hydrated oxygen complexes.

Although oxygen vacancy distributions and dynamics control the operation of solid-oxide fuel cells, understanding the atomistic mechanisms involved during operation of the cell has proved difficult. An approach for the direct mapping of oxygen vacancy concentrations based on local lattice parameter measurements by scanning transmission electron microscopy is now proposed.

The sustained release of both hydrophilic and hydrophobic immunomodulators for metastatic melanoma by nanoscale liposomal polymeric gels administered intratumorally or systemically is demonstrated. It is also shown that such a co-delivery approach delays tumour growth and increases the survival of tumour-bearing mice, and that its efficacy results from the activation of both innate and adaptative immune responses.