The first mobile printer capable of producing thumbnail-sized patches that can carry the mRNA Covid vaccine has been developed by scientists amid hopes that the tool may aid in immunizing individuals in far-flung areas.

Although there are still many obstacles to overcome and the 3D printer is probably years away from becoming a reality, experts applauded the "exciting" finding.

The device prints two-centimeter-wide patches with hundreds of tiny needles in each one, which, when rubbed against the skin, administer a vaccine.

These "microneedle patches" have a number of benefits over conventional shots in the arm, including the ability to be self-administered, the fact that they are relatively painless, the possibility of being more agreeable to vaccine skeptics, and the ability to be kept at room temperature for extended periods of time.

The popular mRNA Covid-19 vaccines from Pfizer and Moderna require refrigeration, which has led to distribution complications -- most notably in developing countries that have criticized the unequal distribution of doses during the pandemic.

The new printer was reportedly tested with the Pfizer and Moderna jabs, as per a study in the journal Nature Biotechnology, but the goal of the international team of researchers behind it is for it to be adapted to whatever vaccines are needed.

Robert Langer, co-founder of Moderna and one of the study's authors, said, as quoted by AFP, that he hoped the printer could be used for "the next Covid, or whatever crisis occurs."

Ana Jaklenec, a study author also from the Massachusetts Institute of Technology, said the printer could be delivered to areas such as refugee camps or remote villages to "quickly immunize the local population," especially in the event of a fresh outbreak of a disease like Ebola.

It is worth noting that there are already microneedle patch vaccines being developed for Covid and a number of other illnesses, such as polio, measles, and rubella.

To avoid past challenges, the researchers employed a vacuum chamber to suck the printer "ink" into the bottom of their patch molds, where it reached the tips of the tiny needles, in order to condense that process.

The mRNA vaccine molecules are contained in lipid nanoparticles that are combined with a polymer resembling sugar water to create the vaccine ink.

The study discovered that the patches may be kept at room temperature for at least six months after drying. Even at a sweltering 37 degrees Celsius (99 degrees Fahrenheit), the patches held up for a month.

Mice that received a vaccine patch generated antibodies at a level comparable to those that received a standard injection, as per the study.

The printed patches are currently being evaluated on primates; if successful, trials on people would follow. 

In 48 hours, the printer can produce 100 patches. However, the researchers added their modeling indicated that it might be able to print thousands a day.