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Fluorescent nanodiamonds (fNDs) containing Nitrogen Vacancy (NV) centres are promising candidates for quantum sensing in biological environments. However, to date, there has been little progress made to combine the sensing capabilities of fNDs with biomimetic substrates used in the laboratory to support physiologically representative cell behaviour. This work describes the fabrication and implementation of electrospun Poly Lactic-co-Glycolic Acid (PLGA) nanofibers embedded with fNDs for optical quantum sensing in an environment, which recapitulates the nanoscale architecture and topography of the cell niche. A range of solutions for electrospinning was prepared by mixing fNDs in different combinations of PLGA and it was shown that fND distribution was highly dependent on PLGA and solvent concentrations. The formulation that produced uniformly dispersed fNDs was identified and subsequently electrospun into nanofibers. The resulting fND nanofibers were characterised using fluorescent microscopy and Scanning Electron Microscopy (SEM). Quantum measurements were also performed via optically detected magnetic resonance (ODMR) and longitudinal spin relaxometry. Time varying magnetic fields external to the fND nanofibers were detected using continuous wave ODMR to demonstrate the sensing capability of the embedded fNDs. The potential utility of fND embedded nanofibers for use as biosensors in physiological environments was demonstrated by their ability to support highly viable populations of differentiated neural stem cells, a major therapeutic population able to produce electrically active neuronal circuits. The successful acquisition of ODMR spectra from the fNDs in the presence of live cells was also demonstrated on cultures of differentiating neural stem cells., Comment: 26 pages, 7 figures

Acoustics offers rich possibilities for characterising and monitoring the biopolymer structures being employed in the field of biomedical engineering. Here we explore the rudimentary acoustic properties of two common biodegradable polymers poly(lactic acid) and poly(lactic-co-glycolic acid). A pulse-echo technique is developed to reveal the bulk speed of sound, acoustic impedance and acoustic attenuation of small samples of the polymer across a pertinent temperature range of 0- 70oC. The glass transition appears markedly as both a discontinuity in the first derivative of the speed of sound and a sharp increase in the acoustic attenuation. We further extend our analysis to consider the role of ethanol whose presence is observed to dramatically modify the acoustic properties and reduce the glass transition temperature of the polymers. Our results highlight the sensitivity of acoustic properties to a range of bulk properties, including visco-elasticity, molecular weight, co-polymer ratio, crystallinity and the presence of plasticizers., Comment: 14 pages, 7 figures

The exclusive ability of acoustic waves to probe the structural, mechanical and fluidic properties of foams may offer novel approaches to characterise the porous scaffolds employed in tissue engineering. Motivated by this we conduct a preliminary investigation into the acoustic properties of a typical biopolymer and the feasibility of acoustic propagation within a foam scaffold thereof. Focussing on poly(lactic-co-glycolic acid), we use a pulse-echo method to determine the longitudinal speed of sound, whose temperature-dependence reveals the glass transition of the polymer. Finally, we demonstrate the first topographic and tomographic acoustic images of polymer foam tissue scaffolds., Comment: 9 pages, 5 figures. Proceedings for the Anglo-French Physical Acoustics Conference, Grasmere, January 2010

Integration of Francophone culture into the language curriculum rests on a suggested three-step approach, involving extensive student research. Goals are (1) recognition of the geography of French-speaking regions; (2) sensitivity to cultural components (e.g., music, art); and (3) familiarity with at least one significant political, historical, social, artistic, or literary figure. (five references) (CNP)