Patches or needles? U. study analyzes vaccine patch administration

Last month, 11 researchers at the Rutgers School of Engineering published their research on a method to more effectively administer vaccines and other medicinal drugs through skin patches rather than injections.

The study by Rutgers researchers and two colleagues from other universities was published in the academic journal "Nature Communications" and details the potential effectiveness of electrospray deposition (ESD) in medical treatment.

Sarah Park, a Ph.D. candidate in the Department of Material Science and Engineering and the first author of the study, said the ESD process entails using a small amount of liquidated medication that is made into a tiny mist by electrification via a patch with micro-sized needles.

Researchers for the study spent time testing different methods to maximize the administered dosage and avoid wasting content that fails to enter a potential patient, Park said.

"The main goal was to enhance the electrospray setup for small targets such that the coating only deposited onto our target and, thus, the amount of active ingredient wasted is minimized," she said.

Park, who is entering her fourth year of working on this research, said one of the biggest challenges for her was working during the height of the pandemic and dealing with outbreaks among researchers. She said her research was deemed essential and was allowed to continue despite coronavirus disease restrictions at the time.

Park said one of the major potential benefits of this research is its role in creating alternative, quicker and more shelf-stable vaccines, as seen during global emergencies like the pandemic.

More traditional hypodermic needle vaccines are in liquid form and require trained handling as well as below-freezing storage, Park said. But the patches' solid coating provides easier transporting and handling, and allows them to be stored at room temperature, she said.

"Regions who do not have the -20 degrees Celsius or -80 degrees Celsius freezer may store these therapeutics at room temperature and still have access to them," she said. "This particular characteristic is important for when availability of the therapeutic is sparse or in the onset of a pandemic where rapid distribution is necessary for containing the spread of disease."

She said steps for the project include potential animal testing before moving on to potential human clinical trials at some point in the future.

"These coated microneedles have great potential to improve accessibility of therapeutics and other treatments," Park said.

The researchers' discoveries, such as a solid coating over the patches' microneedles rather than a liquid diluent, allowed for them to dispense therapeutic drugs into smaller targets without wasting the expensive material.

The final result was a five-step enhancement to the electrospray, said Jonathan Singer, an associate professor in the Department of Mechanical & Aerospace Engineering and a co-author of the study.

He said the team incorporated a negatively polarized ethanol mist every few sprays to counteract any instability in the growing charge. They also installed a large insulated target onto where the microneedles were placed to define a clear target for the droplets, but, due to the insulation, still have it only coat the smaller desired area.

In addition, Park said the use of these patches could lead to rapid availability as patients may be able to administer vaccines onto themselves or, at the very least, have professionals needing less training to administer vaccines.

Park said various repetitive tests were run to improve the efficiency of the electrospray deposition, and they needed to approach 100 percent deposition efficiency for coating the microneedles.

After confirming the coating's functionality, the next step was to write and publish the study, Park said. She said the writing process was smooth in contrast to the publication process, which took almost eight months after submitting the paper since they had to wait to hear back from editors.

"The work in this paper was the culmination of my Ph.D. research thus far, so it was a particularly sentimental experience seeing our results coalesce into its final form of a manuscript," Park said.

Further research is needed in order to fully compare the efficacy of coated microneedles to traditional needles, Park said. Questions to answer include whether microneedles actually create a higher immune response in a patient or not, she said.

In the future, Park said she hopes to use the coated needles in animal experiments to prove their value and eventually implement them in clinical trials. The next challenge that her team also faces is achieving the production speed that would allow for the technology to become readily and commercially available, she said. 

Singer said these patches can expand patient use, especially in terms of self-administration.

"You could envision a future where instead of going and making an appointment with a healthcare provider to receive a vaccine, you're sent a bandaid or something like that — that you put on your arm, and you just leave it in until an indicator goes from red to blue," Singer says.