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Research fellow Adriele Prina- Mello focuses on functional biomaterials, diagnostic devices, and multifunctional nanomaterials for theranostic (a combination of diagnostics and therapy) solutions in the treatment of cancer.

Particle size Fundamental in this work is the understanding of particle size, size distribution and of hydrodynamic response of nanoparticles dependent on their degree of aggregation.

Additionally, being able to measure zeta potential and track particle behaviour in viscous or physiologically relevant media informs the increasing characterisation demands of the nanomedicine community (Fig. 1). Here pressure is on tools providers to offer the most comprehensive and low volume testing of sometimes very expensive samples.

“Our main motivation for such levels of characterisation is determined by the potential use, applicability, and safety aspect linked to nanosize materials.

“Tis allows for further modification of the particle surface coating/ moieties in order to get closer to the suitable candidate for diagnostic, monitoring and therapeutic application for nanomedicine and or biomedical research and also clinical translation,” he says.

To help achieve this, he uses NanoSight’s nanoparticle tracking analysis (NTA).Tis detects and visualises populations of nanoparticles in liquids down to 10 nm, dependent on material, and measures the size of each particle from direct observations of diffusion.

Additionally, NanoSight measures concentration and a fluorescence mode differentiates suitably-labelled particles within complex background suspensions.

Zeta potential measurements are similarly particle-specific. It is this particle-by-particle methodology that takes NTA beyond traditional light scattering and other ensemble techniques in providing high- resolution particle size distributions and validates data with information- rich video files of the particles moving under Brownian motion.

“NanoSight allows for the identification of heterogeneity in particle size, poly-dispersity and counting with simultaneous zeta potential measurement. Furthermore, the use of small sample volumes compared to other techniques allows for cost effective, daily and routine characterisation,” added Prina-Mello.

Regenerative medicine Te promise of repairing damaged hearts through regenerative medicine – infusing stem cells into the heart in

the hope that these cells will replace worn out or damaged tissue – has yet to meet with clinical success. At large part of this failure is thought to be as a result of faulty initial cell placement. But a highly sensitive visualisation technique developed by Stanford University School of Medicine scientists may help overcome that hurdle.

Ultrasound tracking Te new technique employs a trick that marks stem cells so they can be tracked by standard ultrasound as they are squeezed out of the placement needle, allowing their more precise guidance to the spot they are intended to go, and then monitored by magnetic-resonance imaging (MRI) for weeks afterward.

To make this possible, the scientists designed and produced a specialised imaging agent in the form of nanoparticles whose diameters clustered in the vicinity of just below one-third of a micron – less than one-three-thousandth the width of a human hair, or one-thirtieth the diameter of a red blood cell.

Te acoustic characteristics of the nanoparticles’ chief constituent, silica, allowed them to be visualised by ultrasound; they were also doped with the rare-earth element gadolinium, an MRI contrast agent.

Te Stanford group showed that mesenchymal stem cells – a class of

A nano-scale solution to image cellular processes E

uropean scientists are in the process of developing a novel sensing principle at the nano-scale level which will allow cellular processes – particularly

those implicated in cancer - to be monitored much more closely. The EU-funded Dinamo project is developing

biocompatible fluorescent nanodiamond particles (fNDs) for imaging biomolecular interactions in cells. This approach has potential applications in cancer research for detecting the intracellular processes leading to tumour development. Important properties of the nanoparticles include their capacity to be functionalised at the cell surface and

to act as carriers for targeted drug delivery. The Dinamo consortium has developed these

nanoparticles from cost-effective commercial high-pressure high-temperature (HPHT) diamond technology. Following optimisation of the fND production

and fluorescence attachment processes, scientists have generated biocompatible particles that could be visualised by confocal microscopy. Additionally, various chemistries have been

explored for the functionalisation of fNDs. Of particular interest so far are fluorinated particles and those that could be used to detect DNA.

An important achievement of the project is the

application of fNDs for monitoring cellular processes. This is achieved through fluorescent fNDs coupled to specific probes that interact with various biomolecules. This leads to fluorescence resonance energy transfer (FRET), which is in turn exploited for intracellular detection. A successful application of this method consisted of

the targeting of fNDs to cancer breast cells. The Dinamo intracellular biosensors, operating

at the cell or the molecular level, could attract a lot of interest with potentially important applications in the fields of cancer diagnostics and therapy.

“As cancer survival rates increase, the effect of cancer treatments on fertility is critically important to many young patients.”

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