Drugs delivered by nanoparticles hold promise for targeted treatment of many diseases, including cancer. However, the particles have to be injected into patients, which has limited their usefulness so far.
Now, researchers from Massachusetts Institute of Technology (MIT) and Brigham and Women's Hospital (BWH) have designed drug-carrying nanoparticles that can be taken orally.
The new nanoparticles are coated with antibodies that act as a key to unlock receptors found on the surfaces of cells that line the intestine, allowing the nanoparticles to break through the intestinal walls and enter the bloodstream.
This type of drug delivery could be especially useful in developing new treatments for conditions such as high cholesterol or arthritis.
Patients with those diseases would be much more likely to take pills regularly than to make frequent visits to a doctor's office to receive nanoparticle injections, said researchers.
"If you were a patient and you had a choice, there's just no question: Patients would always prefer drugs they can take orally," said Robert Langer, the David H Koch Institute Professor at MIT.
The researchers coated their nanoparticles with Fc proteins - the part of the antibody that binds to the FcRN receptor, which is also found in adult intestinal cells.
The nanoparticles, made of a biocompatible polymer called PLA-PEG, can carry a large drug payload, such as insulin, in their core.
After the particles are ingested, the Fc proteins grab on to the FcRN in the intestinal lining and gain entry, bringing the entire nanoparticle along with them.
"It illustrates a very general concept where we can use these receptors to traffic nanoparticles that could contain pretty much anything," said Rohit Karnik, an MIT associate professor of mechanical engineering.
"Any molecule that has difficulty crossing the barrier could be loaded in the nanoparticle and trafficked across," he said.
The researchers demonstrated oral delivery of insulin in mice. Nanoparticles coated with Fc proteins reached the bloodstream 11-fold more efficiently than equivalent nanoparticles without the coating.
The researchers now hope to apply the same principles to designing nanoparticles that can cross other barriers, such as the blood-brain barrier, which prevents many drugs from reaching the brain.