UK-based Scarlet Therapeutics Ltd has secured a research agreement with the Defense Advanced Research Projects Agency (DARPA) worth up to USD 14 million to develop engineered red blood cells capable of detecting physiological changes and adjusting their therapeutic output in response — a capability distinct from loading static therapeutic proteins into red blood cells.
Scarlet will serve as prime contractor, leading a consortium that includes the University of Bristol, Northwestern University, and Sheffield-based Unicorn Biotechnologies, an automated cell culture manufacturing company. Professor Ash Toye, Scarlet's chief scientific officer and a University of Bristol researcher, will serve as principal investigator. The program is funded under DARPA Agreement HR0011-26-9-E150 and is explicitly described as exploratory, with no clinical use implied.
The platform Scarlet is developing — described by the company as smart red blood cells (SRBCs) — is intended to incorporate sensing and control mechanisms that allow engineered cells to detect physiological signals and modulate their activity accordingly. The program will also advance capabilities in protein retention, biological control, safety, and automated manufacturing, according to the company. Scarlet's foundational technology originated at the University of Bristol and builds on clinical experience from the RESTORE study, a first-in-human trial comparing the survival of lab-grown red blood cells with donated red blood cells in human volunteers.