Metallic Magnetic Nanoparticles for Polymer Microbeads

Polymer microbeads are uniform spheres of polystyrene which can be functionalised so that they will attach to proteins and other entities in blood plasma or other bodily fluids. The microbeads are impregnated with nanoparticles of magnetite, iron oxide so that they can be separated using a magnetic field allowing quantitative analysis or assay. Microbeads are
available in sizes down to 0.3µ but there is a demand for beads with sizes <0.1µ. At this size, it is not possible to get a sufficient loading of magnetite so that the separation of the molecules can be achieved. The only way to increase the magnetic content is to use a metallic material where the magnetisation is 4 times greater.

Liquids Research Ltd (LRL) has held discussions with Merck Chimie who are the largest company in the EU in the microbead market. They have sales in excess of €300M/year in a world market approaching €1B. We are told that there is a substantial and immediate market for metallic magnetic nanoparticles for inclusion in polymer beads. Metallic nanoparticles are
generally unstable in air. Recent academic work indicates that metallic nanoparticles can be encapsulated in a carbon shell rendering them stable. LRL has undertaken a feasibility study funded by the Welsh Assembly Government through the SMART programme and we have reproduced this academic work confirming this result.

The objective of this project is to scale up the production of metallic magnetic nanoparticles >20g batches which would fulfil the requirements set by Merck for production trials of polymer beads. There remain technical issues to be resolved associated with the particles fusing together on a production scale and the dispersion of the in styrene which can be polymerised. In the bio-medical field, there are rigorous specifications for new materials which we will undertake using our ISO9001 accreditation. The achievement of a 20g batch size would be adequate for bead production as the demand is 1kg/year.