Developing a single-molecule fluorescence tool to quantify DNA damage
Biophysical Journal Elsevier 110:3 suppl. 1 (2016) p164a
Abstract:
Quantification of DNA damage is an important technique for medical physics, for example to assess damage caused by the quinolone antibiotics, or to examine the effects of novel cancer treatments such as low-temperature plasma therapy on healthy or tumorous cells. Existing damage quantification techniques such as the alkaline comet assay [1] are often subjective in their results, especially at higher damage levels. Methods using immunofluorescence [2] often lose information due to the three dimensional nature of the cell.Effect of intra-membrane C 60 fullerenes on the modulus of elasticity and the mechanical resistance of gel and fluid lipid bilayers
Nanoscale Royal Society of Chemistry 7 (2015) 17102-17108
Abstract:
Penetration and partition of C60 to the lipid bilayer core are both relevant to C60 toxicity, and useful to realise C60 biomedical potential. A key aspect is the effect of C60 on bilayer mechanical properties. Here, we present an experimental study on the mechanical effect of the incorporation of C60 into the hydrophobic core of fluid and gel phase zwitterionic phosphatidylcholine (PC) lipid bilayers. We demonstrate its incorporation inside the hydrophobic lipid core and the effect on the packing of the lipids and the vesicle size using a combination of infrared (IR) spectroscopy, atomic force microscopy (AFM) and laser light scattering. Using AFM we measured the Young's modulus of elasticity (E) of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) in the absence (presence) of intra-membranous C60 at 24.5 °C. E of fluid phase supported bilayers is not altered by C60, but E increases with incorporation of C60 in gel phase bilayers. The increase is higher for longer hydrocarbon chains: 1.6 times for DPPC and 2 times for DSPC. However the mechanical resistance of gel phase bilayers of curved bilayered structures decreases with the incorporation of C60. Our combined results indicate that C60 causes a decrease in gel phase lipid mobility, i.e. an increase in membrane viscosity.2015 4(th) TERMIS World Congress Boston, Massachusetts September 8-11, 2015.
Tissue engineering. Part A 21 Suppl 1 (2015) S1-S413
Sub-nanoscale free volume and local elastic modulus of chitosan–carbon nanotube biomimetic nanocomposite scaffold-materials
Journal of Materials Chemistry B Royal Society of Chemistry 3:16 (2015) 3169-3176
Abstract:
Future progress in materials for tissue engineering and 3D cell cultures applications requires control of two key physical properties: nanoscale mechanical properties and mass transport. These requirements remain uncontrolled partly due to a lack of physical parameters and quantitative measurements. Using chitosan scaffolds as a model system in close-to-physiological conditions and a combination of experimental techniques and theory, we link structure with local nanomechanical properties. Additionally we introduce a parameter, the free volume, to predict variations in transport properties. By fabricating nanocomposites with single walled carbon nanotubes (SWNTs) we are able to test our approach: incorporation of acid-treated, soluble, [similar]80 nm SWNTs in a chitosan matrix leads to a 2 fold increase in mean local elastic modulus and a decrease of 3% of the free volume available for oxygen diffusion. Inclusion of hydrophobic, [similar]800 nm SWNTs leads to a 100 fold increase of elastic modulus and doubles the voids percentage available for the transport of glucose.Three strategies to stabilise nearly monodispersed silver nanoparticles in aqueous solution.
Nanoscale Res Lett 7:1 (2012) 151