MIT scientists have developed a new technology that may help develop a ‘super injection’ which can deliver all childhood vaccines through a single jab. The three-dimensional (3D) fabrication method can generate a novel type of drug-carrying particle that could allow multiple doses of a vaccine to be delivered over an extended time period with just one injection, researchers said. The new microparticles resemble tiny coffee cups that can be filled with a drug or vaccine and then sealed with a lid. The particles are made of a biocompatible polymer that can be designed to degrade at specific times, spilling out the contents of the “cup.”
“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 would have multiple boosters already built into it,” said Robert Langer, professor at Massachusetts Institute of Technology (MIT) in the US. “This could have a significant impact on patients everywhere, especially in the developing world where patient compliance is particularly poor,” said Langer, senior author of the research published in the journal Science.
The advance could allow babies in developing nations, who might not see a doctor very often, to get one injection after birth that would deliver all of the vaccines they would need during the first one or two years of life, researchers said. Using photolithography, a process used in microfabrication to pattern parts of a thin film or the bulk of a substrate, the researchers created silicon molds for the cups and the lids. Large arrays of about 2,000 molds were fit onto a glass slide, and these molds were used to shape the cups made of PLGA – a biocompatible polymer that has already been approved for use in medical devices such as implants, sutures, and prosthetic devices – and lids.
Once the array of polymer cups formed, the researchers employed a custom-built, automated dispensing system to fill each cup with a drug or vaccine. After the cups are filled, the lids are aligned and lowered onto each cup, and the system is heated slightly until the cup and lid fuse together, sealing the drug inside. In mice, the researchers showed that particles release in sharp bursts, without prior leakage, at 9, 20, and 41 days after injection.
They then tested particles filled with ovalbumin, a protein found in egg whites that is commonly used to experimentally stimulate an immune response. Using a combination of particles that released ovalbumin at 9 and 41 days after injection, they found that a single injection of these particles was able to induce a strong immune response that was comparable to that provoked by two conventional injections with double the dose. The researchers have also designed particles that can degrade and release hundreds of days after injection.