This paper highlights recent advances in synthesis, self-assembly and sensing applications of monodisperse magnetic Co and Co-alloyed nanoparticles. A brief introduction to solution phase synthesis techniques as well as the magnetic properties and aspects of the self-assembly process of nanoparticles will be given with the emphasis placed on selected applications, before recent developments of particles in sensor devices are outlined. Here, the paper focuses on the fabrication of granular magnetoresistive sensors by the employment of particles themselves as sensing layers. The role of interparticle interactions is discussed.

A direct one-step nano-gold printing process from a HAuCl₄ solution precursor is demonstrated using an atmospheric-pressure plasma jet.

Mineralization of bone is a dynamic process, involving a complex interplay between cells, secreted macromolecules, signaling pathways, and enzymatic reactions; the dysregulation of bone mineralization may lead to serious skeletal disorders, including hypophosphatemic rickets, osteoporosis, and rheumatoid arthritis. Very few studies have reported the role of osteocytes - the most abundant bone cells in the skeletal system and the major orchestrators of bone remodeling in bone mineralization, which is owed to their nature of being deeply embedded in the mineralized bone matrix. The Wnt/β-catenin signaling pathway is actively involved in various life processes including osteogenesis; however, the role of Wnt/β-catenin signaling in the terminal mineralization of bone, especially in the regulation of osteocytes, is largely unknown. This research demonstrates that during the terminal mineralization process, the Wnt/β-catenin pathway is downregulated, and when Wnt/β-catenin signaling is activated in osteocytes, dendrite development is suppressed and the expression of dentin matrix protein 1 (DMP1) is inhibited. Aberrant activation of Wnt/β-catenin signaling in osteocytes leads to the spontaneous deposition of extra-large mineralized nodules on the surface of collagen fibrils. The altered mineral crystal structure and decreased bonding force between minerals and the organic matrix indicate the inferior integration of minerals and collagen. In conclusion, Wnt/β-catenin signaling plays a critical role in the terminal differentiation of osteocytes and as such, targeting Wnt/β-catenin signaling in osteocytes may serve as a potential therapeutic approach for the management of bone-related diseases.

Osteogenic differentiation of various adult stem cell populations such as neural crest-derived stem cells is of great interest in the context of bone regeneration. Ideally, exogenous differentiation should mimic an endogenous differentiation process, which is partly mediated by topological cues. To elucidate the osteoinductive potential of porous substrates with different pore diameters (30. nm, 100. nm), human neural crest-derived stem cells isolated from the inferior nasal turbinate were cultivated on the surface of nanoporous titanium covered membranes without additional chemical or biological osteoinductive cues. As controls, flat titanium without any topological features and osteogenic medium was used. Cultivation of human neural crest-derived stem cells on 30. nm pores resulted in osteogenic differentiation as demonstrated by alkaline phosphatase activity after seven days as well as by calcium deposition after 3. weeks of cultivation. In contrast, cultivation on flat titanium and on membranes equipped with 100. nm pores was not sufficient to induce osteogenic differentiation. Moreover, we demonstrate an increase of osteogenic transcripts including Osterix, Osteocalcin and up-regulation of Integrin β1 and α2 in the 30. nm pore approach only. Thus, transplantation of stem cells pre-cultivated on nanostructured implants might improve the clinical outcome by support of the graft adherence and acceleration of the regeneration process. © 2014