Designer Drug Carriers

John Innes Centre scientists have, for the first time, managed to diffuse chemicals through pores 0.8 nanometres in diameter to create a nano-container that could be used to carry drugs to diseased cells in the body.

The external surface of these nano containers could be decorated with molecules that guide them to where they are needed in the body, before the chemical load is discharged to exert its effect on diseased cells. The containers are particles of the Cowpea mosaic virus, which is ideally suited for designing biomaterial at the nanoscale, the report said.

"This is a shot in the arm for all Cowpea mosaic virus technology," says Professor George Lomonossoff of the John Innes Centre, one of the authors on a paper to be published shortly. "This brings a huge change to the whole technology and opens up new areas of research. We don’t really know all the potential applications yet because such particles have not been available before. There is no history of them."

Previous efforts to empty virus particles of their genetic material using irradiation or chemical treatment have been successful in rendering the particles non-infectious, but had not fully emptied the particles.

The research team at the John Innes centre have now discovered they could assemble empty particles from precursors in plants and then extract them to insert chemicals of interest.

Scientists at JIC and elsewhere had also previously managed to decorate the surface of virus particles with useful molecules."But now we can load them too, creating fancy chemical containers," said lead author Dr Dave Evans. "The potential for developing Cowpea mosaic virus as a targeted delivery agent of therapeutics is now a reality," says Dr Evans. Potential applications could be in cancer treatment by targeting molecules known as integrins which appear on cancer cells. The virus particles could be coated externally with peptides that bind to integrins. This would mean the particles seek out cancer cells to the exclusion of healthy cells.
Once bound to the cancer cell, the virus particle would release an anti-cancer agent that has been carried as an internal cargo. The empty viral particles, their use, and the processes by which they are made, are the subject of a new patent filing. Management of the patent and commercialisation of the technology is being handled by PBL.