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Experimental vaccine patch embeds invisible dots under the skin, leaving record of immunization

A close-up microscope image of the microneedle array, which could deliver quantum dots into skin.K.J. MCHUGH ET AL., SCIENCE TRANSLATIONAL MEDICINE

Ana Jaklenec readily acknowledges she’s inspired by “Star Trek.” The Massachusetts Institute of Technology scientist envisions a future in which devices like Mr. Spock’s tricorder scan the body for health information, making medical records relics of the past.

Today, though, they are still crucial. Global health experts attribute some of the 1.5 million deaths each year from vaccine-preventable diseases to gaping holes in medical record-keeping, especially in developing countries where resources to properly document immunizations may be lacking.

To solve that problem, Jaklenec and her bioengineering colleagues have devised a way to deliver a vaccine through a microneedle patch that simultaneously embeds in the skin a pattern of fluorescent nanocrystals about the vaccination itself. It’s a record that’s invisible to the naked eye, written in quantum dots that emit near-infrared light readable by a modified smartphone. It doesn’t require any link to a database and it doesn’t tie into any personal information, the scientists say, anticipating concerns about privacy.

They describe their experimental platform in a study published Wednesday in Science Translational Medicine.

“In much of the world we don’t have good records of individual child immunizations,” said Dr. Walter Orenstein, associate director of the Emory Vaccine Center, who was not involved in the research. “What this is attempting to do is in essence give people a living record so that when you come back to the clinic, they can determine what immunizations you already had and thus can then decide what immunizations or further immunizations you need, if any.”

Childhood immunizations are typically given in multiple doses over the first five years of life, so knowing what a child does or doesn’t need is critical. Keeping track of immunizations can be challenging in wealthy countries, where electronic health records may be incompatible between different health care providers. But in developing countries, where paper vaccination cards or even Sharpie marks on a child’s fingernails serve as documentation, it can seem insurmountable.

“It would be really exciting if you could deliver vaccine and then be able to go back and figure out in your population how well you are doing,” said Dr. Wilbur Chen of the Center for Vaccine Development and Global Health at the University of Maryland School of Medicine, who was not involved in the study.

Currently, in some countries vaccination rates are estimated by doses shipped by the government to local health centers, Chen said. There can be financial rewards for high rates, potentially distorting what is reported and leaving people unprotected. Some vaccination campaigns are met with suspicion, hampering efforts to eradicate polio, for example.

Chen was on a team invited by Ethiopia’s Ministry of Health in 2015 to evaluate vaccination of children in rural parts of the country. Checking on immunization rates meant taking blood samples and testing them in a lab, a cumbersome process impractical for routine care but sobering for the mismatch they found in 2018 between reported and actual vaccination rates.

The MIT scientists designed their device to offer simplicity and immediacy. Still in the prototype stage, its staying power has been successfully tested in skin from human cadavers exposed to a simulated five years of sunlight. Its efficacy at delivering polio vaccine along with the fluorescent quantum dots has been confirmed in rats.

Comparing the Covid-19 vaccines developed by Pfizer, Moderna, and Johnson & Johnson

The next step, before trials in people, is to test its feasibility among experts in the field: health care workers serving the families whose children would receive the vaccine and its quantum dots encapsulating the fluorescent nanocrystals. A contract research organization will take a prototype that does not contain vaccine into the field and ask people in different countries how it feels and what they think about the whole concept.

Orenstein of Emory doesn’t think the encoded vaccine history raises privacy concerns.

“It’s not visible and it requires a special device to read. Vaccines are recommended for everybody,” he said. “The big issue is the need to assure it’s safe. It would need to pass regulatory controls and it would need to gain acceptance in the community.”

Jaklenec is turning to Particles for Humanity, a startup she and Robert Langer, MIT professor, prolific entrepreneur, and a co-author of the journal article, founded to bring technologies like these to developing countries where vaccination campaigns are going on.

“My hope is that this scientific work could someday have a significant impact in terms of enabling patients in the developing world to receive the correct vaccines when needed and, in so doing, potentially save many lives,” Langer said.

At MIT, the team is developing ways to encode more information about a vaccine, such as lot number or time and date of administration.

“The paper is one step, and we show one example of using it to encode information about vaccination,” Jaklenec said. “I think we have the potential to do other things as well, even to go back to Mr. Spock, to maybe even sense something in the body using these signals. Perhaps we could make things that can give us information about changes in the body.”

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