Nanoparticles deliver drugs under immune system radar

A team from Brighton and Copenhagen universities found that subtle differences in the architecture of nanoparticle surface coatings had a marked effect on immune system response — essentially allowing them to engineer a particle with ’stealth properties’.

Nanoparticles are increasingly being investigated in drug delivery as they can potentially carry their payload directly to diseased cells or tumours with a reduced dosage and therefore fewer side effects.

However, there are still some major obstacles to overcome before they become mainstream, as project collaborator Dr Christy Hunter from Brighton told The Engineer: ‘One of the key issues, if you look at all the nanomedicines that are used at the moment, is that they can cause anaphylactic-type reactions in patients.

‘If you don’t understand the immunology of the interactions, these medicines will never really come to true fruition — you have to have an absolute mechanistic understanding.’

The team started with polystyrene particles of a similar size to viruses at around 50–200nm. However, when injected into the blood these particles were intercepted by an enzyme cascade called the complement system (which is part of the larger immune system).