Saving patients’ breath

Microscopic plastic spheres that can be inhaled into the lungs could provide a new weapon in the treatment of lung cancer.

The particles, developed by Prof Justin Hanes of the department of chemical and biomechanical engineering at Johns Hopkins University in Baltimore, contain medicines and are painless to administer.

They could also be used to deliver DNA directly into the nucleus of cells for use in gene therapy.

The particles are made from a combination of three biodegradable plastic monomers. Each of the materials has already been approved by the US Food and Drug Administration (FDA) for use in other medical applications, meaning they are unlikely to pose any health hazard to humans in their polymeric form.

The lungs are an ideal route for delivering drugs to the body, as when medicine is swallowed it must pass through the acid of the stomach, where it may be degraded.

Once inside the lungs the balls begin to dissolve, releasing their cargo at a predetermined pace over a matter of hours, days or even weeks. This will allow constant drug delivery over a period of time, doing away with the need for painful injections.

Coupled with newly developed drugs able to target specific cells, the particles could one day deliver tumour-targeting medications capable of identifying and attacking cancer cells within the lung.

The materials used to create the micro-spheres are both strong and flexible to ensure that the balls do not crack before they reach the lung. They are also designed so that they do not stick together in the air passages, preventing them from reaching their target, and avoid triggering the body’s immune responses.

‘We have designed the material of the particles so we can control surface properties to counteract forces such as capillary and electrostatic force, to stop them from absorbing too much or too little water and sticking together,’ said Hanes.

‘They are also given a coating to stop them absorbing proteins that might cause them to be recognised as foreign bodies by the lung’s defences. Almost anything can be put inside them.’

Hanes is now building on this research by improving the inhalation particles, each of which is about a tenth of the diameter of a human hair. He is also attempting to produce even smaller particles that could eventually be used to deliver drugs directly into the diseased cells themselves, preventing harm to surrounding cells.