In vitro 3D tissue modelling: Insights into ameloblastoma pathogenesis

Ameloblastoma is a rare, benign oral tumour. Tumours develop within the jaw bone and are highly destructive and invasive, with cells migrating into the jaw and surrounding soft tissue. This is a little-understood disease which if left untreated causes dramatic bone destruction and maxillofacial disfigurement. Current treatment is radical surgery, often resulting in extensive loss of function and tissue. An ameloblastoma-derived cell line, AM-1, has been established [1]. Cells were isolated from a human tumour and immortalised by the addition of HPV-16 DNA. This study aims to (i) make a 3D in vitro ameloblastoma disease model, using plastic-compressed collagen gel [2] seeded with AM-1 cells, and (ii) use this bone construct to characterise tissue remodelling, cell growth and invasiveness

Collagen gel as a 3D in vitro tissue model for ameloblastoma studies

Ameloblastoma is a rare locally invasive epithelial odontogenic tumour of the jaw which can cause significant and debilitating bone destruction. In vitro studies of ameloblastoma are sparse in the literature, and little is known regarding patterns of ameloblastoma cell growth and invasion, as well as relevant gene and protein expression. This study aims to (i) use plastic-compressed collagen gels as a robust and relevant biomimetic to culture ameloblastoma cells in a 3D in vitro tissue model [1] and (ii) perform histology, immunohistochemistry (IHC) and gene expression assays to characterise tissue remodelling, cell growth and invasiveness

Comparison of 20nm silver nanoparticles synthesized with and without a gold core: Structure, dissolution in cell culture media, and biological impact on macrophages

Widespread use of silver nanoparticles raises questions of environmental and biological impact. Many synthesis approaches are used to produce pure silver and silver-shell gold-core particles optimized for specific applications. Since both nanoparticles and silver dissolved from the particles may impact the biological response, it is important to understand the physicochemical characteristics along with the biological impact of nanoparticles produced by different processes. The authors have examined the structure, dissolution, and impact of particle exposure to macrophage cells of two 20 nm silver particles synthesized in different ways, which have different internal structures. The structures were examined by electron microscopy and dissolution measured in Rosewell Park Memorial Institute media with 10% fetal bovine serum. Cytotoxicity and oxidative stress were used to measure biological impact on RAW 264.7 macrophage cells. The particles were polycrystalline, but 20 nm particles grown on gold seed particles had smaller crystallite size with many high-energy grain boundaries and defects, and an apparent higher solubility than 20 nm pure silver particles. Greater oxidative stress and cytotoxicity were observed for 20 nm particles containing the Au core than for 20 nm pure silver particles. A simple dissolution model described the time variation of particle size and dissolved silver for particle loadings larger than 9 μg/ml for the 24-h period characteristic of many in-vitro studies

Analytical transmission electron microscopy at organic interfaces

Organic materials are ubiquitous in all aspects of our daily lives. Increasingly there is a need to understand interactions between different organic phases, or between organic and inorganic materials (hybrid interfaces), in order to gain fundamental knowledge about the origin of their structural and functional properties. In order to understand the complex structure–property–processing relationships in (and between) these materials, we need tools that combine high chemical sensitivity with high spatial resolution to allow detailed interfacial characterisation. Analytical transmission electron microscopy (TEM) is a powerful and versatile technique that can fulfil both criteria. However, the application of analytical TEM to organic systems presents some unique challenges, such as low contrast between phases, and electron beam sensitivity. In this review recent analytical TEM approaches to the nanoscale characterisation of two systems will be discussed: the hybrid collagen/mineral interface in bone, and the all-organic donor/acceptor interface in OPV devices

Resolving the size of ice-nucleating particles with a balloon deployable aerosol sampler: the SHARK

Ice-nucleating particles (INPs) affect cloud development, lifetime, and radiative properties, hence it is important to know the abundance of INPs throughout the atmosphere. A critical factor in determining the lifetime and transport of INPs is their size; however very little size-resolved atmospheric INP concentration information exists. Here we present the development and application of a radio-controlled payload capable of collecting size-resolved aerosol from a tethered balloon for the primary purpose of offline INP analysis. This payload, known as the SHARK (Selective Height Aerosol Research Kit), consists of two complementary cascade impactors for aerosol size-segregation from 0.25 to 10 µm, with an after-filter and top stage to collect particles below and above this range at flow rates of up to 100 L min−1. The SHARK also contains an optical particle counter to quantify aerosol size distribution between 0.38 and 10 µm, and a radiosonde for the measurement of temperature, pressure, GPS altitude, and relative humidity. This is all housed within a weatherproof box, can be run from batteries for up to 11 h, and has a total weight of 9 kg. The radio control and live data link with the radiosonde allow the user to start and stop sampling depending on meteorological conditions and height, which can, for example, allow the user to avoid sampling in very humid or cloudy air, even when the SHARK is out of sight. While the collected aerosol could, in principle, be studied with an array of analytical techniques, this study demonstrates that the collected aerosol can be analysed with an offline droplet freezing instrument to determine size-resolved INP concentrations, activated fractions, and active site densities, producing similar results to those obtained using a standard PM10 aerosol sampler when summed over the appropriate size range. Test data, where the SHARK was sampling near ground level or suspended from a tethered balloon at 20 m altitude, are presented from four contrasting locations having very different size-resolved INP spectra: Hyytiälä (southern Finland), Leeds (northern England), Longyearbyen (Svalbard), and Cardington (southern England)

Chemical speciation of nanoparticles surrounding metal-on-metal hips.

Spectromicroscopy of tissue surrounding failed CoCr metal-on-metal hip replacements detected corroded nanoscale debris in periprosthetic tissue in two chemical states, with concomitant mitochondrial damage. The majority of debris contained Cr(3+), with trace amounts of oxidised cobalt. A minority phase containing a core of metallic chromium and cobalt was also observed