Spray technique for bioactive materials promises injection-free vaccinations

The technique could lead to a new era of transdermal medication, including injection-free vaccinations, the researchers said.

The team has developed a new approach to electrospray deposition that better controls the target region within a spray zone and the electrical properties of microscopic particles that are being deposited. The greater command of those two properties means that more of the spray is likely to hit its microscopic target. Their results are detailed in Nature Communications.

In electrospray deposition, manufacturers apply a high voltage to a flowing liquid, converting it into fine particles. Each of those droplets evaporates as it travels to a target area, depositing a solid precipitate from the original solution.

“While many people think of electrospray deposition as an efficient method, applying it normally does not work for targets that are smaller than the spray, such as the microneedle arrays in transdermal patches,” said Jonathan Singer, an associate professor in the Department of Mechanical and Aerospace Engineering in the Rutgers School of Engineering and an author on the study. “Present methods only achieve about 40 per cent efficiency. However, through advanced engineering techniques we’ve developed, we can achieve efficiencies statistically indistinguishable from 100 per cent.”

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Coatings are used on medical devices implanted into the body, such as stents, defibrillators and pacemakers and they are beginning to be used more frequently in new products employing biologicals, including transdermal patches.

“We were looking to evaluate if electrospray deposition, which is a well-established method for analytical chemistry, could be made into an efficient approach to create biomedically active coatings,” Singer said in a statement.

Higher efficiencies could be the key to making electrospray deposition more appealing for the manufacture of medical devices using bioactive materials such as drugs and vaccines, researchers said.

“Being able to deposit with 100 per cent efficiency means none of the material would be wasted, allowing devices or vaccines to be coated in this way,” said Sarah Park, a doctoral student in the Department of Materials Science and Engineering who is first author on the paper. “We anticipate that future work will expand the range of compatible materials and the material delivery rate of this high‐efficiency approach.”

Unlike other coating techniques used in manufacturing, the new electrospray deposition technique is characterised as ‘far field,’ meaning that it doesn’t need highly accurate positioning of the spray source, the researchers said. Consequently, the equipment necessary to employ the technique for mass manufacturing would be more affordable and easier to design.