Design strategies for shape-controlled magnetic iron oxide nanoparticles

Ferrimagnetic iron oxide nanoparticles (magnetite or maghemite) have been the subject of an intense research, not only for fundamental research but also for their potentiality in a widespread number of practical applications. Most of these studies were focused on nanoparticles with spherical morphology but recently there is an emerging interest on anisometric nanoparticles. This review is focused on the synthesis routes for the production of uniform anisometric magnetite/maghemite nanoparticles with different morphologies like cubes, rods, disks, flowers and many others, such as hollow spheres, worms, stars or tetrapods. We critically analyzed those procedures, detected the key parameters governing the production of these nanoparticles with particular emphasis in the role of the ligands in the final nanoparticle morphology. The main structural and magnetic features as well as the nanotoxicity as a function of the nanoparticle morphology are also described. Finally, the impact of each morphology on the different biomedical applications (hyperthermia, magnetic resonance imaging and drug delivery) are analysed in detail. We would like to dedicate this work to Professor Carlos J. Serna, Instituto de Ciencia de Materiales de Madrid, ICMM/CSIC, for his outstanding contribution in the field of monodispersed colloids and iron oxide nanoparticles. We would like to express our gratitude for all these years of support and inspiration on the occasion of his retirement

Cu-Doped Extremely Small Iron Oxide Nanoparticles with Large Longitudinal Relaxivity: One-Pot Synthesis and in Vivo Targeted Molecular Imaging

Synthesizing iron oxide nanoparticles for positive contrast in magnetic resonance imaging is the most promising approach to bring this nanomaterial back to the clinical field. The success of this approach depends on several aspects: the longitudinal relaxivity values, the complexity of the synthetic protocol, and the reproducibility of the synthesis. Here, we show our latest results on this goal. We have studied the effect of Cu doping on the physicochemical, magnetic, and relaxometric properties of iron oxide nanoparticles designed to provide positive contrast in magnetic resonance imaging. We have used a one-step, 10 min synthesis to produce nanoparticles with excellent colloidal stability. We have synthesized three different Cu-doped iron oxide nanoparticles showing modest to very large longitudinal relaxivity values. Finally, we have demonstrated the in vivo use of these kinds of nanoparticles both in angiography and targeted molecular imaging

Effects of habitat fragmentation on the abortion and predation of seeds in Chaco Serrano = Efectos de la fragmentación sobre la aborción y depredación de semillas en el Chaco Serrano

Habitat fragmentation can have consequences on plant reproduction through several interactions with insects. We studied the effects of habitat fragmentation in die proportion of aborted, predated and undamaged seeds of Acacia aroma and Cercidium praecox. We performed this study in the Chaco Serrano of Argentina. We found that fragmentation effects differed between species. In small patches, the number of aborted seeds of A. aroma increased and the number of pre–dispersal predated seeds and undamaged seeds of C. praecox decreased and increased, respectively. However, higher numbers of aborted seeds in small patches did not lead to fewer available seeds for dispersion. For these species, seed predation by bruchids was about 35 percent and aborted seeds were around 7 percent. Because of the elevated levels of damage and the high specificity of bruchids, the changes caused by habitat fragmentation may be very important for the populations of these two species. Habitat fragmentation effects on pollination and pre–dispersal seed predation of these legumes may determine higher availability of seeds for dispersion in fragmented habitats