The research, funded by the Bill and Melinda Gates Foundation, has led to the creation of a 3-D fabrication method for microstructures made from the biocompatible polymer PLGA – already approved in medical devices such as implants and prosthetics.
These structures “resemble tiny coffee cups that can be filled with a drug or vaccine and then sealed with a lid,” according to the team from Massachusetts Institute of Technology (MIT) and, due to the nature of the polymer, degrade at explicit times administering (or ‘lifting the lid and spilling’) the API or vaccine to the patient.
"They can be injected subcutaneously or intramuscularly (IM) and remain at the injected location due to their micron size," Ana Jaklenec, a research scientist at MIT’s Koch Institute for Integrative Cancer Research and a senior author on the paper published on the research, told us.
The concept has the potential to deliver multiple doses of a drug, or even a full vaccination regimen into the patient through a single injection.
“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,” drug delivery pioneer Robert Langer from the David H. Koch Institute Professor at MIT said.
This could be particularly of interest in the developing world, where visits to a doctor are limited. A child could theoretically receive all his or her vaccines and booster shots through one injection.
The microstructures are made using MIT’s SEAL (StampEd Assembly of polymer Layers) technology platform, drawn from computer chip manufacturing.
Silicon moulds for the cups and the lids were created using photolithography and a custom-built, automated dispensing system employed to fill the cups with API or vaccines. The lids are then slightly heated and fused on.
“Each layer is first fabricated on its own, and then they’re assembled together,” Jaklenec said. “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.”
She added the method of manufacture can be used with any thermoplastic material and could have broad applications for injectable pulsatile drug delivery, pH sensors, and 3-D microfluidic devices, for example.
And according to Jaklenec, MIT is in discussion with several pharmaceutical companies regarding scale up and further development of this technology.
"We are working with several commercial and R&D vaccines to show efficacy of our single injection micro-cups. Additionally, we are looking to set up a manufacturing facility so that we can move as fast as possible to get to human trials," she told us.