Engineers from MIT have devised a new method that could benefit millions by allowing delivery of more than one drug or vaccine with a single injection. They have designed a new type of drug-carrying particle that when injected could deliver the drugs or vaccines in blood over a period of time as desired.
In their latest research they explained that these new drug-carrying particles look like microscopic coffee cups that can be filled with the vaccines or the drugs before finally capping them off with a lid. The material with which the cups are made of are biocompatible and an polymer that has been approved by the US FDA. At a specific time, these cups or vessels can degrade within the body and thus release the drugs.
Robert Langer, the David H. Koch Institute Professor at MIT said that this is a very exciting work since for the first time a team can create an array of “tiny, encased vaccine particles” which would release the drugs at absolutely precise and predetermined time. This means that no booster shots for vaccines would be necessary. Persons can take a single shot of the vaccine and it would know when to release the booster shot into the blood stream. This would be especially beneficial in the developing nations he explained since most individuals there missed their booster shots due to poor adherence to the vaccine schedules. Ana Jaklenec, a research scientist at MIT’s Koch Institute for Integrative Cancer Research, postdoc Kevin McHugh and Thanh D. Nguyen, assistant professor of mechanical engineering at the University of Connecticut also worked with Langer on this study. The findings of their study are published online in Science on September 14th 2017. The project was funded by the Bill and Melinda Gates Foundation.
Langer has earlier worked to develop a polymer particle that can carry the embedded drugs throughout the particle, releasing them over time. That was a steady and sustained release of the embedded drugs. For this study they wanted to develop a mechanism by which short bursts of the drug or vaccine would be released at specific time intervals. This would mimic the vaccine schedules they explained.
For this they developed this sealable coffee cup style design made from PLGA. This is a polymer that has been approved for use in medical devices including prosthetics, implants and suture materials. This polymer degrades at varied rates and thus can carry drugs that would be released at different predetermined time. Then the team went on to use 3-D printing techniques to make the cups. But routine 3-D printing proved to be difficult to use for this purpose because of the microscopic sizes desired. So they devised a new way to make these tiny cups using techniques used to design microchips for computers. They used photolithography to make moulds of silicon for the cups and the lids. Each glass slide had a line of around 2,000 molds that were used to shape the PLGA cups. The cups were cube shaped with length of a few hundred microns only. Once a line of cups were made, a custom made dispensing system delivered the drugs or vaccines into the cups. Once filled, another automated machine helped align the lids and with the help a bit of heat sealed the lids in place. This sealed the vaccines within the cups.
Jaklenec explained that each of the layers are made separately and then assembled. Also this new technique that could not be achieved with 3D printing is termed SEAL (StampEd Assembly of polymer Layers) Jaklenec said. SEAL can be used in other areas too such as injectable pulsatile drug delivery or 3D microfluid delivery systems or pH sensors etc.
The team then showed that in mice the new devices could release the medications sealed within them in sharp bursts with no leakage at 9th, 20th and 41st days after the initial injection. Some of these particles can release after hundreds of days as designed. As a next step the team is not testing these delivery particles with inactivated polio vaccine and other newly developing vaccines.
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