The COVID-19 pandemic highlighted an urgent need for efficient, durable, and widely accessible vaccines. This prompted several important innovations in vaccine technology, and researchers continue to explore new and creative ways to make effective vaccines rapidly available to the greatest number of people.

In a study published in December in Scientific Reports, researchers from the Institute of Industrial Science, The University of Tokyo have revealed that 3D-printing technology can be used to enhance the effectiveness of a cutting-edge vaccine delivery technique.

Conventional vaccination methods require skilled medical personnel to administer them, which can delay mass immunization efforts. Microneedle array patches (MAPs) are a promising alternative to standard vaccines, as they are painless, more stable at room temperature, and can be self-administered.

"MAPs are made by pouring a viral solution into a mold that shapes it into an array of tiny needles as it dries," says lead author of the study Kotaro Shobayashi. "When the patch is applied to the skin, these microneedles dissolve, delivering the vaccine to the patient."

Using MAPs to deliver live virus can be challenging, however, as the whole dose is not always delivered, and some of the virus dies during fabrication. To address this, the researchers created a 3D-printed backing layer for MAPs consisting of a series of tiny plastic pillars. This backing layer is inserted into the MAP mold, much like placing wooden sticks in a popsicle mold, so that the viral solution forms dissolvable needles at the tip of each pillar.

"Once we had constructed the pillar-guided MAP, we tested how much live virus it retained compared with normal MAPs," explains Beomjoon Kim, senior author. "Then, we tested the vaccine efficacy of the pillar-guided MAPs in mice."

Incorporating the 3D-printed pillar backing layer decreased drying time, which resulted in more live virus being preserved in the MAP. Furthermore, the pillar-guided MAPs induced specific immune responses in mice that protected them against lethal SARS-CoV-2 infection.

"Our findings show that pillar-guided MAPs are a promising platform for delivering virus vaccines," says Shobayashi.

Given that MAPs offer a painless and self-administrable option for vaccination, this approach could help promote COVID-19 immunization worldwide. It could be especially useful in areas where refrigeration is not available, as live virus is stable at room temperature in this form.

The article, "Precision dosing of recombinant vaccinia vaccine via pillar-guided microneedle patch confers SARSCoV-2 immunity," was published in Scientific Reports at DOI: 10.1038/s41598-025-29183-z.

Research Contact

Kim Beomjoon, Professor
Institute of Industrial Science, the University of Tokyo
Tel：+81-3-5452-6224
E-mail: bjoonkim (Please add "@iis.u-tokyo.ac.jp" to the end)