Scientists use biodegradable polymers to deliver multiple vaccines in one jab

Scientists have developed a way of delivering multiple drugs or vaccines in just one injection. 

Researchers at the Massachusetts Institute of Technology developed containers that are hollow, injectable and made of polymer microparticles. The containers can be filled with a drug or vaccine and are designed to break down at various points in time to release the contained fluid.

The microparticles are made of a biocompatible, FDA approved polymer that are filled with a drug or a vaccine and then sealed with a lid. The microparticles, which resemble miniature coffee cups, are then heated slightly so that the cups and the lid fuse together to seal the drug inside.

The researchers state that the slow-release microparticles can improve ‘drug availability, reduce side effects and allow for more constant dose delivery’. It could also allow babies in developing nations to get all the vaccines they need during the first one or two years of life.

Ana Jaklenec, a research scientist at MIT’s Koch Institute for Integrative Cancer Research, said: “Each layer is first fabricated on its own, and then they’re assembled together. Part of the novelty is really in how we align and seal the layers. In doing so we developed a new method that can make structures which current 3-D printing methods cannot. This new method called SEAL (StampEd Assembly of polymer Layers) can be used with any thermoplastic material and allows for fabrication of microstructures with complex geometries that could have broad applications, including injectable pulsatile drug delivery, pH sensors, and 3-D microfluidic devices.”

The researchers tested the technology on mice, injecting them with three different polymers, each filled with a fluorescent substance. The researchers then used imaging techniques to see when the substance was released and found it last around nice days, 20 days or 41 days, depending on which polymer they used.

The researchers also simulated an immune response in the mice by using a combination of particles that released at nine and 41 days. The team found that single injection of these particles induced a strong immune response that was similar to that of two regular injections with double dose.

Robert Langer, the David H. Koch Institute professor at MIT said: “We are very excited about this work because, for the first time, we can create a library of tiny, encased vaccine particles, each programmed to release at a precise, predictable time, so that people could potentially receive a single injection that, in effect, would have multiple boosters already built into it. This could have a significant impact on patients everywhere, especially in the developing world where patient compliance is particularly poor.”

The team have also designed particles that can break down after hundreds of days and are now testing the particles with a number of drugs and vaccines.