Beating the cystic fibrosis barrier

Cystic fibrosis is a hereditary disease that kills thousands each year because it is difficult to treat, but scientist in America have synthesised nanosized particles able to deliver medication across the mucus barrier characteristic of the disease.

Biodegradable nanoparticles capable of penetrating the mucus barrier in the lungs and gut of cystic fibrosis (CF) sufferers have been developed by researchers at John Hopkins University, led by Justin Hanes, professor of chemical and biomolecular engineering.

“Cystic fibrosis mucus is notoriously thick and sticky, and represents a huge barrier to aerosolised drug delivery,” said Pamela Zeitlin, CF expert and professor of paediatrics, who collaborated on the study.  “Nanoparticles were engineered to travel through cystic fibrosis mucus at a much greater velocity than ever before, thereby improving drug delivery,” she said.

The nanoparticles comprise of two parts made of molecules regularly used in existing medications.  An inner core of polysebacic acid (PSA) traps therapeutic agents inside while a dense outer coating of polyethylene glycol (PEG) molecules allows the particle to move through the mucus by preventing it from reacting with proteins.

Hanes previously demonstrated that latex coated with PEG could slip past mucus coatings, but because the body could not break it down into harmless components it was impractical. “The major advance here is that we were able to make biodegradable nanoparticles that can rapidly penetrate thick and sticky mucus secretions and that these particles can transport a wide range of therapeutic molecules,” said Hanes.

The nanoparticles have potential applications treating lung and cervical cancers, and inflammation of the sinuses, eyes, lungs and gastrointestinal tract where mucus is produced to protect sensitive areas, said Benjamin C Tang, lead author and postdoctoral fellow in the department of chemical and biomolecular engineering.  Zeitlin concludes: “This work is critically important to moving forward with the next generation of small molecule and gene-based therapies.”