The biological effects of engineered nanoparticles are presently a focus of interest in chemistry, biology, pharmacology, clinical medicine, and toxicology due to the enormous therapeutic and diagnostic potential that the particulate nature of nanoparticles offers for selective drug delivery and controlled release. This raises unprecedented safety issues, calling for novel paradigms to face the biocompatibility analysis of particulate (as opposed to molecular) bioactive agents that vary in shape, surface, and charge, in addition to chemical structure. This issue of MRS Bulletin focuses on the bioeffects of metal oxide nanostructures, whose high bioactivity can be exploited to design novel multifunctional devices for nanomedical applications, some of which are already undergoing testing in anticancer and antioxidant clinical trials. The ubiquitous application in research and technology of these non-biodegradable structures has evoked concerns regarding their potential hazards, due to the same chemical activities that promise nanomedical developments. A Janus-type scenario is emerging, pointing to intricate networks of beneficial and detrimental effects following the biological interactions of metal oxide nanoparticles.

In my Von Hippel Award talk, I emphasized my connection to Arthur von Hippel since our meeting in 1960, when Arthur von Hippel was 62 years of age, but still spanning the last 40 years of his life. He was a Renaissance man with many broad interests. I also spoke about the work that was cited in my award and our overlapping activities. Professor von Hippel was a mentor to me in my early career, and he worked to advance my career behind the scenes. Even after his passing a decade before my selection for the Von Hippel Award, I continue to be influenced by his teachings about science, as well as about his enjoyment of the practice of science and the life of a scientist. Professor von Hippel’s views on the foundations of materials research have strongly influenced the Materials Research Society, and this viewpoint is also emphasized in my article and by my own research career, which has been recognized by the Von Hippel Award.

Tissue engineering and regenerative medicine aim to achieve functional restoration of tissue or cells damaged through disease, aging, or trauma. Advancement of tissue engineering requires innovation in the field of three-dimensional scaffolding and functionalization with bioactive molecules. Nanotechnology offers advanced materials with patterned nano-morphologies for cell growth and different molecular substrates that can support cell survival and functions. Cerium oxide nanoparticles (nanoceria) can control intracellular as well as extracellular reactive oxygen and nitrogen species. Recent findings suggest that nanoceria can enhance long-term cell survival, enable cell migration and proliferation, and promote stem cell differentiation. Moreover, the self-regenerative property of nanoceria permits a small dose to remain catalytically active for an extended time. This review summarizes the possibilities and applications of nanoceria in the field of tissue engineering and regenerative medicine.

Neurological pathologies and nerve damage are two problems of significant medical and economic impact because of the hurdles of losing nerve functionality in addition to significant mortality and morbidity, and demanding rehabilitation. There are currently a number of examples of how nanotechnology can provide new solutions for biomedical problems. Current strategies for nerve repair rely on the use of functionalized scaffolds working as “nerve guidance channels” to improve axonal regeneration and to direct axonal re-growth across the nerve lesion site. Since low invasiveness and high selectivity of the growth stimulation are usually conflicting requirements, new approaches are being pursued in order to overcome such limitations. Engineered magnetic nanoparticles (MNPs) have emerged from this need for noninvasive therapies for both positioning and guiding neural cells in response to an external magnetic field. Here, we review the current state of the use of MNPs for neuroprotective and magnetically guided therapies. We discuss some conceivable outcomes of current magnetically driven strategies seeking integrated platforms for regenerative action on damaged tissues.

Cobalt was doped into the Ce-doped SrMnO3 system to enhance the low ionic conductivity of Ce-doped SrMnO3 (SCM) for solid oxide fuel cell cathode application. Structural and conductivity changes as a function of the Co content were investigated. Sr0.9Ce0.1Mn1–x Cox O3−δ (SCMCo, x = 0.1, 0.2, 0.3) cathode materials were synthesized by an EDTA citrate complexing process, which yielded a single perovskite structure, and the lattice volume was expanded by substituting Ce and Co ions. The increased lattice volume was attributed to a decrease in the valence state of the manganese and cobalt and an increase in the oxygen vacancy concentration. An increase in the concentration of oxygen vacancies with increasing Co content was identified by thermogravimetric analysis. The electrical conductivity decreased with increasing Co content, which was attributed to an increase in the activation energy for polaron hopping. Although the electrical conductivity was decreased by cobalt-doping, the polarization resistance of SCMCo also decreased significantly (from 5.611 to 1.171 Ω cm2 at 800 °C). The decreased polarization resistance is attributed to enhanced oxygen-ion transfer kinetics with cobalt-doping. We conclude that cobalt substitution leads to enhancement in the electrochemical properties of the cathode due to an increase in oxygen vacancy concentration.

The dispersion of carbon nanotubes is one of the problems in the application of polymer nanocomposites. In this study, the effect of chemical functionalization of the carbon nanotube surface on the dispersion of the tubes within a polymer is reported. The effect of carbon nanotube weight loading on the properties of polymer membrane was also studied. Multiwalled carbon nanotubes were dispersed in Nafion® matrix by melt processing techniques to form nanocomposite membranes. The morphology, dc electrical conductivity, thermal stability, mechanical properties, and proton conductivity of these nanocomposites were investigated. Nitric acid functionalized carbon nanotubes were evenly dispersed with Nafion as observed by scanning electron microscopy. The measurements of mechanical properties indicate that this processing method and carbon nanotube loading can improve the modulus of the nanocomposites.

The feasibility of an accelerated test method on revealing the high cycle fatigue (HCF) limit stresses of a near alpha titanium alloy was successfully verified firstly during the rotary bending tests. The stress-controlled low cycle fatigue (LCF) tests at room temperature were then carried out over a range of maximum stresses and stress ratios to reveal the basic LCF strength. Finally, the core emphasis was focused on the influences of the predamage from LCF loadings on the subsequent HCF limit stresses corresponding to the life of 106 cycles. A total of eight levels of predamage from LCF with different stress levels, stress ratios, and proportions of LCF life were introduced, which resulted in obvious deterioration of the HCF stress limits (even under only 2% of expected LCF life). The fracture analysis exhibited that there were typical LCF failure characteristics in crack initiation regions of specimens under prior LCF loadings.

Methods for the solution deposition of organic semiconductors (OSCs) show great potential for the production of large-area, inexpensive, and flexible organic electronics. A solution deposition method called solution shearing has consistently been shown to yield thin film transistors with improved performance over those created via other solution-based approaches. However, the need for discrete, electronically isolated devices requires the parallel development of a facile means of pattern definition compatible with the solution shearing process. In our work, we use a simple chemical prepatterning method to enable the solution shearing deposition of the small molecule OSC TIPS-pentacene on substrates with feature sizes as small as 100 µm. Grazing incidence x-ray diffraction (GIXD) was also used to confirm the existence of high performance TIPS-pentacene polymorphs in the patterned thin films. Mobilities as high as 1.13 cm2 V−1 s−1 were obtained on 400 µm wide patterns by depositing a high-performance, metastable polymorph of TIPS-pentacene.