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There is an ongoing demand for new approaches for treating localized bone pathologies. Here we propose a new strategy for treatment of such conditions, via local delivery of hormones/drugs to the trauma site using drug releasing nano-engineered implants. The proposed implants were prepared in the form of small Ti wires/needles with a nano-engineered oxide layer composed of array of titania nanotubes (TNTs). TNTs implants were inserted into a 3D collagen gel matrix containing human osteoblast-like, and the results confirmed cell migration onto the implants and their attachment and spread. To investigate therapeutic efficacy, TNTs/Ti wires loaded with parathyroid hormone (PTH), an approved anabolic therapeutic for the treatment of severe bone fractures, were inserted into 3D gels containing osteoblast-like cells. Gene expression studies revealed a suppression of SOST (sclerostin) and an increase in RANKL (receptor activator of nuclear factor kappa-B ligand) mRNA expression, confirming the release of PTH from TNTs at concentrations sufficient to alter cell function. The performance of the TNTs wire implants using an example of a drug needed at relatively higher concentrations, the anti-inflammatory drug indomethacin, is also demonstrated. Finally, the mechanical stability of the prepared implants was tested by their insertion into bovine trabecular bone cores ex vivo followed by retrieval, which confirmed the robustness of the TNT structures. This study provides proof of principle for the suitability of the TNT/Ti wire implants for localized bone therapy, which can be customized to cater for specific therapeutic requirements., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Titanium implants can fail due to inappropriate biomechanics at the bone-implant interface that leads to suboptimal osseointegration. Titania nanotubes (TNTs) fabricated on Ti implants by the electrochemical process have emerged as a promising modification strategy to facilitate osseointegration. TNTs enable augmentation of bone cell functions at the bone-implant interface and can be tailored to incorporate multiple functionalities including the loading of active biomolecules into the nanotubes to target anabolic processes in bone conditions such as osteoporotic fractures. Advanced functions can be introduced, including biopolymers, nanoparticles and electrical stimulation to release growth factors in a desired manner. This review describes the application of TNTs for enhancing osteogenesis at the bone-implant interface, as an alternative approach to systemic delivery of therapeutic agents.

To treat skeletal conditions such as bone infections, osteoporotic fractures, and osteosarcoma, it would be ideal to introduce drugs directly to the affected site. Localized drug delivery from the bone implants is a promising alternative to systemic drug administration. In this study we investigated electrochemically nanoengineered Ti wire implants with titania nanotubes (TNTs), as minimally invasive drug-releasing implants for the delivery of drugs directly into the bone tissue. Since trabecular bone in vivo contains a highly interconnected bone marrow, we sought to determine the influence of marrow on drug release and diffusion. Electrochemical anodization of Ti wires (length 10 mm) was performed to create an oxide layer with TNTs on the surface, followed by loading with a fluorescent model drug, Rhodamine B (RhB). Cores of bovine trabecular bone were generated from the sternum of a young steer, and were processed to have an intact bone marrow, or the marrow was removed. RhB-loaded TNTs/Ti wires were inserted into the bone cores, which were then cultured ex vivo using the ZetOS™ bioreactor system to maintain bone viability. Release and diffusion of RhB inside the bone was monitored using fluorescence imaging and different patterns of drug transport in the presence or absence of marrow were observed. Scanning electron microscopy of the implants after retrieval from bone cores confirmed survival of the TNTs structures. Histological investigation showed the presence of bone cells adherent on the implants. This study shows a potential of Ti drug-releasing implants based on TNTs technology towards localized bone therapy. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 714-725, 2016., (© 2015 Wiley Periodicals, Inc.)

Here, we report a detailed and systematic approach for studying the in vitro nanotoxicity study of high aspect ratio (HAR) nanomaterials using anodic alumina nanotubes (AANTs) as a nanomaterial model. AANTs with bio-inert properties and tailored aspect ratios ranging from 7.8 to 63.3 were synthesized by an electrochemical pulse anodization process. Cytotoxicity studies were conducted with RAW 264.7 mouse macrophage cells and MDA-MB 231-TXSA human breast cancer cells through several toxicity parameters, including cell viability and morphology, pro-inflammatory response, mitochondrial depolarization, lysosomal membrane permeabilization (LMP), induction of autophagy and endoplasmic reticulum (ER) stress. The resulting toxicity patterns were cell-type dependent and strongly related with AANTs dose, length of time, and importantly the AR of AANTs. Long AANTs triggered enhanced cell death, morphological changes, tumor necrosis factor α (TNF-α) release, LMP and ER stress than short AANTs. The toxic AR window of AANTs was determined to be 7.8, which is shorter than that of other previously reported HAR nanomaterials. This toxic AR window provides a promising opportunity to control the nanotoxicity of HAR nanomaterials for their advanced drug delivery application., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

In this study, we report about the structural engineering and optical optimization of nanoporous anodic alumina rugate filters (NAA-RFs) for real-time and label-free biosensing applications. Structurally engineered NAA-RFs are combined with reflection spectroscopy (RfS) in order to develop a biosensing system based on the position shift of the characteristic peak in the reflection spectrum of NAA-RFs (Δλpeak). This system is optimized and assessed by measuring shifts in the characteristic peak position produced by small changes in the effective medium (i.e., refractive index). To this end, NAA-RFs are filled with different solutions of d-glucose, and the Δλpeak is measured in real time by RfS. These results are validated by a theoretical model (i.e., the Looyenga-Landau-Lifshitz model), demonstrating that the control over the nanoporous structure makes it possible to optimize optical signals in RfS for sensing purposes. The linear range of these optical sensors ranges from 0.01 to 1.00 M, with a low detection limit of 0.01 M of d-glucose (i.e., 1.80 ppm), a sensitivity of 4.93 nm M(-1) (i.e., 164 nm per refractive index units), and a linearity of 0.998. This proof-of-concept study demonstrates that the proposed system combining NAA-RFs with RfS has outstanding capabilities to develop ultrasensitive, portable, and cost-competitive optical sensors.

Diatoms are unicellular, eukaryotic, photosynthetic algae that are found in aquatic environments. Diatoms have enormous ecological importance on this planet and display a diversity of patterns and structures at the nano- to millimetre scale. Diatom nanotechnology, a new interdisciplinary area, has spawned collaborations in biology, biochemistry, biotechnology, physics, chemistry, material science and engineering. We survey diatom nanotechnology since 2005, emphasizing recent advances in diatom biomineralization, biophotonics, photoluminescence, microfluidics, compustat domestication, multiscale porosity, silica sequestering of proteins, detection of trace gases, controlled drug delivery and computer design. Diatoms might become the first organisms for which the gap in our knowledge of the relationship between genotype and phenotype is closed.

Diatoms produce diverse three-dimensional regular silica structures with nanometer to micrometer dimensions and hold considerable promise for biological and biomimetic fabrication of nanostructured materials and devices. In the present work, we describe the ultrastructural characterization of porous structures in diatom biosilica and discuss their potential as membrane filters for diffusion based separations. The frustules of two centric diatom species, Coscinodiscus sp. and Thalassiosira eccentrica, were investigated using scanning electron microscopy and atomic force microscopy. Their morphological features, including pore size, shape, porosity, and pore organization, are described. We observed that although pore organization in frustules of Thalassiosira eccentrica and Coscinodiscus sp. is in reverse order, a striking commonality is the size range of the smallest pores in both species (around 40 nm). The consensus lower pore size suggests that frustule valves have a common function at this size of excluding viruses or other deleterious particles, and the pore size and organization is optimized for this purpose. We suggest and implement an experimental approach to study the potential of diatom frustules for diffusive separation of molecular or nanoparticular components in microfluidic or lab-on-a-chip environments.

In the current paper, we reviewed the use of nanoparticles (NPs) in crop protection, emphasizing the control of pests in the agricultural and urban environment. At the same time, we provide the framework on which the technology of NPs is based and the various categories of NPs that are currently used for pest control. Apart from the use of NPs as carriers of a broad category of active ingredients, including insecticides and pheromones, some NPs can be used successfully as insecticides alone. Moreover, several types of NPs are produced by natural resource-based substances, which make them promising 'green' alternatives to the use of traditional pest control agents. Finally, the potentials in the use of NPs are briefly illustrated and discussed. [ABSTRACT FROM AUTHOR]