The new ‘crystalline shield’ that could end the need for daily insulin

For people with Type 1 diabetes, cell transplants could finally end the need for daily insulin injections. But there’s a catch: the body’s immune system quickly attacks foreign cells, forcing patients to rely on powerful immune-suppressing drugs that prevent rejection but carry serious long-term risks.

Now, an international team led by researchers at Johns Hopkins University has made a major advance in solving that problem. Featured on the cover of the January 2026 edition of Science Translational Medicine, the study introduces a novel “crystalline shield” that protects cells for up to a year—without shutting down the patient’s entire immune system.

“Ultimately, this discovery moves us closer to a future where chronic diseases might be managed with long-lasting implantable systems rather than lifelong, systemic immune suppression,” said Joshua Doloff, an associate professor of biomedical engineering at Johns Hopkins and study co-author.

For decades, scientists have worked to enclose donor cells in tiny capsules that can be implanted to sense blood sugar and release insulin as needed. While capsules shield cells from direct attack, the immune system quickly pivots, turning its attention to rejecting the capsule material itself.

In previous work, Doloff’s team identified a specific immune regulator called colony-stimulating factor-1 receptor (CSF1R) as the primary driver behind biomaterial “foreign body” rejection. To block this pathway, the team engineered a CSF1R‑blocking drug into compact crystals. Unlike standard liquid drugs that quickly dissipate, these crystals stay in place to provide protection that lasts for months or even years.

Further, cells within encapsulation devices face an additional persistent hurdle: nearby immune cells are capable of releasing toxic molecules that can seep through capsule walls. This process —known as indirect rejection—gradually poisons the cells inside over weeks or months until the transplant finally fails.

To solve this, the team co-encapsulated these slow-dissolving crystals with the donor cells, creating a sustained, localized release of medicine around the implant. In preclinical tests, the shields prevented indirect rejection and kept allografts—cells transplanted between members of the same species—alive and functional for durations ranging from a month to a year.

According to Doloff, this latest study is the first time these components have been integrated into a working “crystalline shield” on this scale.

“This success provides a vital proof-of-concept for how the technology would perform in human-to-human transplants,” said Doloff. “It shows the shield is powerful enough to withstand the aggressive immune responses by the body.”

The breakthrough was a multi-institutional effort led by Doloff, Shady Farah at the Technion-Israel Institute of Technology, and Matthew Bochenek of MIT. The team also included key contributors from Harvard University, the University of Massachusetts, the University of Virginia, and CellTrans Inc.

To bridge the gap to the clinic, the team is moving into a new phase of research supported by a $1.1 million grant from Breakthrough T1D. While the crystalline shield has shown success in initial lab models, the next step involves testing it against the more aggressive immune responses seen in humans.