The synthesis and study of so-called “nanoparticles”, particles with diameters in the range of 1−20 nm, has become a major interdisciplinary area of research over the past 10 years. Semiconductor nanoparticles promise to play a major role in several new technologies. The intense interest in this area derives from their unique chemical and electronic properties, which gives rise to their potential use in the fields of nonlinear optics, luminescence, electronics, catalysis, solar energy conversion, and optoelectronics, as well as other areas. The small dimensions of these particles result in different physical properties from those observed in the corresponding macrocrystalline, “bulk”, material. As particle sizes become smaller, the ratio of surface atoms to those in the interior increase, leading to the surface properties playing an important role in the properties of the material. Semiconductor nanoparticles also exhibit a change in their electronic properties relative to that of the bulk material; as th...

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Nanocrystalline semiconductors: Synthesis, properties, and perspectives

Morphology development and crystal growth in nanocrystalline aggregates under hydrothermal conditions: insights from titania

http://www.ianano.org/Workshop-ICNT2005/Webster/webster-handout-1.pdf

Increased osteoblast adhesion on nanophase metals: Ti, Ti6Al4V, and CoCrMo.

For the continuous monitoring, diagnosis, and treatment of neural tissue, implantable probes are required. However, sometimes such neural probes (usually composed of silicon) become encapsulated with non-conductive, undesirable glial scar tissue. Similarly for orthopaedic implants, biomaterials (usually titanium and/or titanium alloys) often become encapsulated with undesirable soft fibrous, not hard bony, tissue. Although possessing intriguing electrical and mechanical properties for neural and orthopaedic applications, carbon nanofibres/nanotubes have not been widely considered for these applications to date. The present work developed a carbon nanofibre reinforced polycarbonate urethane (PU) composite in an attempt to determine the possibility of using carbon nanofibres (CNs) as either neural or orthopaedic prosthetic devices. Electrical and mechanical characterization studies determined that such composites have properties suitable for neural and orthopaedic applications. More importantly, cell adhesion experiments revealed for the first time the promise these materials have to increase neural (nerve cell) and osteoblast (bone-forming cell) functions. In contrast, functions of cells that contribute to glial scar-tissue formation for neural prostheses (astrocytes) and fibrous-tissue encapsulation events for bone implants (fibroblasts) decreased on PU composites containing increasing amounts of CNs. In this manner, this study provided the first evidence of the future that CN formulations may have towards interacting with neural and bone cells which is important for the design of successful neural probes and orthopaedic implants, respectively.

http://iopscience.iop.org/article/10.1088/0957-4484/15/1/009/pdf

Nano-biotechnology: carbon nanofibres as improved neural and orthopaedic implants

The structures of Fe2O3 nanoparticles with different sizes were investigated using Fe K-edge X-ray absorption near-edge structure (XANES) and the FEFF calculations, as well as surface modification with enediol ligands. The studies not only revealed the existence of under-coordinated Fe sites in the nanoparticles but also confirmed that these under-coordinated sites were located on the surface. Upon binding of enediol ligands, surface sites were restructured to octahedral sites. In particular, the nature of the surface defects and their correlation with the unique properties of the nanoparticles were discussed. Model calculations were conducted for FemOn (m ≥ 1, n ≥ 4) clusters of various sizes centered at Fe sites with octahedral (Oh), distorted octahedral (C3v) and tetrahedral (Td) coordination geometry using FEFF8.10 programs. The main features of the calculated spectra agree with the experimental results and were correlated to the density of states, the Fe coordination geometry, and the long-range orde...

Richard W. Siegel

Papers

Creating Nanophase Materials