‘Microjet’ devices could help replace needle injections

Small devices placed in the body inspired by cephalopods could be the next step in reducing people’s reliance on needle-injected medications.

The devices, detailed in a new paper in Nature, were developed by researchers at the Massachusetts Institute of Technology, Brigham and Women’s Hospital, and Novo Nordisk. Like using a water flosser to puncture a balloon instead of a pin, they use “microjets” to penetrate gastrointestinal tissue and distribute their payload without using a needle (2024, DOI: 10.1038/s41586-024-08202-5). The team is developing two types of the devices: one tethered endoscopic version for use in health care settings and one ingestible version that, in theory, could be used at home.

While small, swallowable devices aren’t new, similar devices with these needleless microjet systems are a recent development.

“Potentially reducing or even eliminating needles stands to potentially enhance the safety, acceptability, and management of these systems or devices because we recognize that needles require training if they’re being administered externally, but also management from a downstream perspective,” says Giovanni Traverso, one of the lead authors on the study.

The devices can be designed to deliver their payloads in either radial directions, useful for narrow tubes of tissue like the esophagus or small intestine, or axial directions, useful for more cavernous areas like the stomach—inspired by how cephalopods can change the direction of their jets. This directionality is important for making sure the products are actually injected into the tissue layers instead of being ineffectively dispersed into the space of the lumen. The hope is that these devices can help replace needles, which are cumbersome both at home and in hospital settings because of sharps disposal protocols, the need for training, and patient discomfort. Both the ingestible radial and axial devices are comparable in size to a size 000 pill capsule, which at 26.1 mm long is one of the largest pill sizes.

The team found that in ex vivo tissues, the microjet was similarly effective at administering insulin, GLP-1 analogs, and siRNA compared to an injection. They also tested the microjets in vivo in pig and dog stomachs and intestines and found similar results.

But for the ingestible radial and axial devices, the team did not test whether the devices could be swallowed safely—they were inserted directly into the intestine and stomach, respectively. Niren Murthy, a bioengineering professor at the University of California, Berkeley, who was not involved with the study, says that would be one of the next aspects to address.

The capsule containing the device may have to be pH sensitive to determine where in the body it would release. If it were to be swallowed and the payload was intended for the intestine instead of the stomach, it would still “spend a long time in the stomach. And somehow you have to make it so that the pill doesn’t explode or release in the stomach, but then releases in the small intestine,” he says.