Injection method developed to deliver multiple vaccine doses in one shot

Sept. 18 (UPI) -- Engineers at MIT have created a 3D fabrication method that can make a new drug-carrying particle to allow multiple doses of a drug, vaccine with one injection.

The new microparticles are similar to small coffee cups that are filled with a drug or vaccine, and then closed with a lid. The microparticles are made of a biocompatible polymer designed to degrade at specific a time, which releases the contents of the cup.

"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," Robert Langer, a professor at MIT, said in a press release. "This could have a significant impact on patients everywhere, especially in the developing world where patient compliance is particularly poor."

The study, published Friday in Science, details the development of a sealable polymer cup made from PLGA, an FDA-approved biocompatible polymer used in implants and prosthetic devices.

Researchers used photolithography to create silicon molds for the cups and lids, using arrays of 2,000 molds fit onto a glass slide to shape the PLGA cups and lids.

The team then used a custom-built, automated dispensing system to fill each cup with a drug or vaccine. Lids are then aligned and lowered onto each cup, and heated to fuse the cup and lid together to seal the drug inside.

"Each layer is first fabricated on its own, and then they're assembled together," said Ana Jaklenec, a research scientist at MIT's Koch Institute for Integrative Cancer Research. "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 3D 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."

Researchers demonstrated the microparticles' ability to release drugs in sharp bursts at nine, 20 and 41 days after injection on lab mice. The team found that a single injection of these particles was able to induce a strong immune response, comparable to that provoked by two conventional injections with double the dose.

"The SEAL technique could provide a new platform that can create nearly any tiny, fillable object with nearly any material, which could provide unprecedented opportunities in manufacturing in medicine and other areas," Langer said.

The research was funded by the Bill and Melinda Gates Foundation and could allow babies in developing countries, who may not see a doctor on a regular basis, to get one injection after birth that would deliver all of the vaccines needed during the first year or two of life.