A Novel Method for Producing Functional Nanoparticles for Medical Applications

An exciting aspect of Nanotechnology is its multidisciplinarity that crosses barriers between physics, chemistry and biology. Recently it has been explored for new cancer therapies, which conventionally use toxic drugs resulting in a balancing act between harming the patient and treating the cancer. A nanotechnology-based approach is to use magnetic nanoparticles less than 10 nanometres across (5,000 times smaller than the width of a human hair) attached to ‘targeting molecules’ that locate and attach only to cancer cells. Once in place an oscillating external magnetic field heats the particles and their attached cells, thereby killing them, without harming healthy tissue. This gentle treatment is the so-called ‘magic bullet’ approach and has been shown to work in principle in early clinical trials but is hindered by the available nanoparticles not producing enough heat. In a recent breakthrough at Leicester, the Condensed Matter Physics group in Physics and Astronomy developed a new method of producing suspensions of highly magnetic bio-compatible nanoparticles that will generate 5-10 times as much heat per particle as existing fluids. The grant will support a collaboration between Physics, Chemistry and the Leicester General Hospital to develop the technology, conjugate the nanoparticles with targeting molecules and test the new suspensions for their tumour-killing performance in vitro.

There is an intense research effort focused on the application of nanoparticles to medical diagnosis and therapy. The applicant, who is a physicist, specialises in the production and properties of size-selected gas-phase magnetic nanoparticles with diameters in the range 1 - 10nm. Recently, with support from the EPSRC s Life Science Interface (LSI) pogramme, proof-of-principle was demonstrated in a novel method for depositing gas-phase nanoparticles into liquids. This is an important development for medical applications since physical gas-phase methods for producing nanoparticles are by far the most versatile and are able to produce mono-sized particles of virtually any material with good size control. In addition it is possible to prepare complex nanoparticles with core-shell morphologies and alloy constituents, which cannot be produced chemically, for example particles with an FeCo core coated in a Au shell. Now that the technical problem of depositing them into liquids has been solved it is possible to prepare liquid suspensions of nanoparticles with all the above properties and in an environment in which they can be functionalised by attaching biological moieties. These can be targeting molecules, such as nanobodies (targeting paratopes of monoclonal antibodies), peptides or vitamins that locate receptors specific to tumour cells. Thus the particles can be used for targeted image enhancement or targeted treatment through hyperthermia. Further development is needed to enable the source to produce nanoparticle suspensions with good size and volume fraction control. In addition it will be upgraded to be able to produce core-shell particles. By working in a collaboration with the Leicester General Hospital and the Leicester University Chemistry Department, the programme will demonstrate the performance of the functionalised nanoparticles with hyperthermia in vitro. It is envisaged that by the end of the project the source will be close to commercialisation for supply to medical research laboratories.