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Edmundson M.,University of Cardiff | Thanh N.T.K.,Royal Institution of Great Britain | Thanh N.T.K.,University College London | Song B.,University of Cardiff
Theranostics | Year: 2013

Stem cell therapies offer great potentials in the treatment for a wide range of diseases and conditions. With so many stem cell replacement therapies going through clinical trials currently, there is a great need to understand the mechanisms behind a successful therapy, and one of the critical points of discovering them is to track stem cell migration, proliferation and differentiation in vivo. To be of most use tracking methods should ideally be non-invasive, high resolution and allow tracking in three dimensions. Magnetic resonance imaging (MRI) is one of the ideal methods, but requires a suitable contrast agent to be loaded to the cells to be tracked, and one of the most wide-spread in stem cell tracking is a group of agents known as magnetic nanoparticles. This review will explore the current use of magnetic nanoparticles in developing and performing stem cell therapies, and will investigate their potential limitations and the future directions magnetic nanoparticle tracking is heading in. © Ivyspring International Publisher. Source

Crick C.R.,University College London | Bear J.C.,University College London | Southern P.,Royal Institution of Great Britain | Parkin I.P.,University College London
Journal of Materials Chemistry A | Year: 2013

A general method for the synthesis of a novel class of superhydrophobic polymer thin films with embedded nanoparticles is presented. These materials combine the superhydrophobic nature of silicone polymer matrices and the properties of the nanoparticles for photocatalysis, magnetic applications, or high surface area catalysis. The films themselves are deposited using a one-pot aerosol assisted chemical vapour deposition (AACVD) process, and are characterised using electron microscopy, X-ray dispersive spectroscopy, water contact angle and bouncing measurements and elemental mapping. We show that these materials demonstrate multifunctional behaviour through magnetic, catalytic and superhydrophobic measurements. © The Royal Society of Chemistry 2013. Source

Yildirimer L.,University College London | Thanh N.T.K.,University College London | Thanh N.T.K.,Royal Institution of Great Britain | Loizidou M.,University College London | Seifalian A.M.,University College London
Nano Today | Year: 2011

In recent years, nanoparticles (NPs) have increasingly found practical applications in technology, research and medicine. The small particle size coupled to their unique chemical and physical properties is thought to underlie their exploitable biomedical activities. Here, we review current toxicity studies of NPs with clinical potential. Mechanisms of cytotoxicity are discussed and the problem of extrapolating knowledge gained from cell-based studies into a human scenario is highlighted. The so-called 'proof-of-principle' approach, whereby ultra-high NP concentrations are used to ensure cytotoxicity, is evaluated on the basis of two considerations; firstly, from a scientific perspective, the concentrations used are in no way related to the actual doses required which, in many instances, discourages further vital investigations. Secondly, these inaccurate results cast doubt on the science of nanomedicine and thus, quite dangerously, encourage unnecessary alarm in the public. In this context, the discrepancies between in vitro and in vivo results are described along with the need for a unifying protocol for reliable and realistic toxicity reports. © 2011 Elsevier Ltd. Source

Yildirimer L.,University College London | Thanh N.T.K.,University College London | Thanh N.T.K.,Royal Institution of Great Britain | Seifalian A.M.,University College London
Trends in Biotechnology | Year: 2012

Skin wounds are a major social and financial burden. However, current treatments are suboptimal. The gradual comprehension of the finely orchestrated nature of intercellular communication has stimulated scientists to investigate growth factor (GF) or stem cell (SC) incorporation into suitable scaffolds for local delivery into wound beds in an attempt to accelerate healing. This review provides a critical evaluation of the status quo of current research into GF and SC therapy and subsequent future prospects, including benefits and possible long-term dangers associated with their use. Additionally, we stress the importance of a bottom-up approach in scaffold fabrication to enable controlled factor incorporation as well as production of complex scaffold micro- and nanostructures resembling that of natural extracellular matrix. © 2012 Elsevier Ltd. Source

Christie I.N.,University College London | Wells J.A.,University College London | Southern P.,Royal Institution of Great Britain | Marina N.,University College London | And 3 more authors.
NeuroImage | Year: 2013

The combination of optogenetics and functional magnetic resonance imaging (fMRI) is referred to as opto-fMRI. Optogenetics utilises genetic engineering to introduce light sensitive actuator proteins into cells. Functional MRI (fMRI) is a specialist form of magnetic resonance imaging concerned with imaging changes in blood flow and oxygenation, linked to regional variation in metabolic activity, in the brain. This study describes a methodological concern regarding the effects of light delivery into the brain for the purposes of opto-fMRI. We show that blue light delivery to the naïve rat brain causes profound fMRI responses, despite the absence of optogenetic activation. We demonstrate that these fMRI responses are dependent upon laser power and show that the laser causes significant heating. We identify how heating impacts upon the MR signal causing NMR frequency shifts, and T1 and T2* changes. This study brings attention to a possible confounder which must be taken into account when opto-fMRI experiments are designed. © 2012 Elsevier Inc.. Source

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