Scientists Successfully Re-Engineer Living Red Blood Cells in Mice to Act as Long-Lasting Drug and Imaging Vehicles

New research shows red blood cells can be tagged "in vivo" to carry drugs and imaging agents for over 40 days, offering a safer alternative to traditional delivery.

By: AXL Media

Published: Mar 24, 2026, 4:58 AM EDT

Source: Information for this report was sourced from Nature Communications

Transforming the Circulatory System’s Workhorses

Red blood cells (RBCs) comprise over 99% of all blood cells and possess a naturally long lifespan, making them ideal candidates for transporting medicine through the body. Traditionally, engineering these cells required a complex, expensive, and risky process of extracting blood, modifying it in a lab, and re-infusing it into the patient. However, a new study published in Nature Communications describes a "metabolic glycoengineering" technique that skips these steps entirely. By injecting a specialized azido-sugar directly into the bloodstream, researchers were able to install chemical handles onto the membranes of living RBCs while they were still in circulation.

The Mechanism of Metabolic Glycoengineering

The process involves the administration of tetraacetyl-N-azidoacetylmannosamine (AAM), an azido-sugar that cells naturally absorb and incorporate into their outer membranes. These sugars act as chemical "hooks," allowing scientists to attach various payloads—such as imaging dyes or hormones—using a highly stable method known as "click chemistry." Because RBCs do not divide like other cells, these tags remain fixed to the cell for its entire functional life. In mouse models, these tags persisted for 42 days, nearly the total lifespan of a murine red blood cell, providing a remarkably stable platform for long-term medical intervention.

Achieving High-Precision Specificity

One of the primary challenges in "in vivo" tagging is ensuring the chemical hooks only stick to the intended target. While the azido-sugars initially labeled various cell types, including white blood cells (WBCs) and organ tissues, these non-target cells metabolize and divide much faster than RBCs. By day seven, the study found that the number of tagged red blood cells was nearly 4,000 times higher than tagged white blood cells. This natural decay in non-target areas creates a "targeting window" where physicians can attach drugs specifically to the long-lasting RBCs with minimal risk of off-target effects in other tissues.