A self-boosting vaccine that can give multiple doses at different times is being developed by scientists.
One shot would provide multiple measurements of an inoculation through microparticles that release payloads at separate intervals, according to new research.
These microparticles look like tiny coffee cups sealed with a lid and the vaccine could fight a host of diseases – from measles to COVID, the scientists said.
The particles stay under the skin until the vaccine is released and then break down, just like absorbable stitches.
They could be especially useful for delivering childhood vaccines in areas where people don’t have regular access to medical care, said the team from MIT’s Koch Institute for Integrative Cancer Research in Cambridge, Massachusetts.
It also opens the door to providing a range of other therapies, including cancer drugs, hormone treatments and other medicines, experts said.
“This is a platform that can be widely applicable to all types of vaccines, including recombinant protein vaccines, DNA-based vaccines, even RNA-based vaccines” , said Dr. Ana Jaklenec, lead author of the study.
“Understanding the vaccine release process, which we have described in this article, has allowed us to work on formulations that address some of the instability that might be induced over time.”
The particles are made from PLGA, a biocompatible polymer that has already been approved for use in medical devices such as implants, sutures and prostheses.
The team created sets of silicone molds to shape the “cups” and “lids”. Once assembled, they used a bespoke automated dispensing system to fill each cup with a drug or vaccine.
Once the cups are filled, the lids are aligned and lowered onto each cup. The system is slightly heated until the cup and lid fuse – sealing the medicine inside.
The technique called SEAL (StampEd Assembly of polymer Layers) makes it possible to produce particles of any shape or size.
“We wanted to mechanistically understand what is happening and how this information can be used to help stabilize drugs and vaccines and optimize their kinetics,” Jaklenec said.
Analysis of the release mechanism revealed that the polymers are gradually cleaved by water.
When there is enough, the lid becomes very porous. Very soon after, they go their separate ways, spilling content.
“We realized that the sudden formation of pores before the moment of release is the key that leads to this pulsatile release,” said Ph.D. Morteza Sarmad. candidate and lead author of the study.
“We don’t see any pores for a long period of time, then all of a sudden we see a significant increase in the porosity of the system.”
A variety of design parameters, including size, shape, and polymer composition, affect the timing of drug release.
“If you want the particle to release after six months for a certain application, we use the corresponding polymer, or if we want it to release after two days, we use another polymer,” Sarmadi said.
“A wide range of applications can benefit from this observation.”
When water breaks them down, the byproducts include lactic acid and glycolic acid, which make the environment more acidic.
It can damage the drugs inside – usually proteins or nucleic acids. Researchers are now working on ways to counteract the effect and improve stability.
A computer model can predict how a particular particle will degrade. It could be used to guide the development of other microfabricated or 3D printed particles or medical devices.
A self-boosting polio vaccine is already being tested on animals. Usually the polio vaccine should be given in a series of two to four separate injections.
“We believe that these core shell particles have the potential to create a safe, single-shot, self-boosting vaccine in which a cocktail of particles with different release times can be created by altering the composition,” said Prof. Robert Langer, a co-lead author of the study.
“Such a single injection approach has the potential to not only improve patient compliance, but also to increase cellular and humoral immune responses to the vaccine.”
The method is already showing promise for the treatment of diseases such as cancer. Two years ago, researchers showed they could deliver drugs that stimulate a pathway called STING.
In mice, it stimulated immune responses. After being injected into tumors, the particles delivered multiple doses of the drug for several months, inhibiting growth and reducing the spread of disease.
The study was published in the journal Scientists progress.
Produced in association with SWNS.
This story was provided to Newsweek by Zenger News.