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The method for creating coatings of biologically active materials, which could lead to new types of transdermal medication, was developed by researchers at Rutgers University in New Jersey.
Writing in Nature Communications, the team described a new approach to electrospray deposition, an industrial spray-coating process. The researchers developed a way to better control the target region within a spray zone, as well as the electrical properties of microscopic particles that are deposited, the research announcement said. “The greater command of those two properties means that more of the spray is likely to hit its microscopic target,” the announcement added.
In electrospray deposition, manufacturers apply a high voltage to a flowing liquid, such as a biopharmaceutical, 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 associate professor Jonathan Singer, an author on the study. “Present methods only achieve about 40% efficiency. However, through advanced engineering techniques we’ve developed, we can achieve efficiencies statistically indistinguishable from 100%.”
Coatings are increasingly important for a variety of medical applications. They are used on medical devices implanted into the body, such as stents, defibrillators and pacemakers. They are also beginning to be used more frequently in new products using biological materials, such as transdermal patches.
Advanced biological or ‘bioactive’ materials – such as drugs and vaccines – can be costly to produce, especially if any of the material is wasted, which can greatly limit whether a patient can receive a given treatment.
“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.
Higher efficiencies could be the key to making electrospray deposition more appealing for the manufacture of medical devices using bioactive materials, the researchers said.
“Being able to deposit with 100% efficiency means none of the material would be wasted, allowing devices or vaccines to be coated in this way,” said doctoral student Sarah Park, 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, such as dip coating and inkjet printing, the new electrospray deposition technique is characterised as “far field,” meaning it does not need highly accurate positioning of the spray source, the researchers said. As a result, the equipment necessary to use the technique for mass manufacturing could be more affordable and easier to design.
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