Penn Engineers Redesign mRNA Delivery Vehicles to Boost Vaccine Potency and Slash Liver Toxicity

Penn Engineers develop aroLNPs that target lymph nodes and avoid the liver, potentially making mRNA vaccines more potent with fewer side effects.

By: AXL Media

Published: Mar 24, 2026, 9:01 AM EDT

Source: Information for this report was sourced from University of Pennsylvania School of Engineering and Applied Science

Engineering a More Precise mRNA Delivery System

The University of Pennsylvania School of Engineering and Applied Science has introduced a significant advancement in the architecture of lipid nanoparticles, the microscopic vehicles used to transport mRNA into human cells. By modifying the ionizable lipid component of these particles, researchers have successfully redirected their path through the body, prioritizing the immune system's primary training grounds. According to Michael J. Mitchell, Associate Professor in Bioengineering and senior author of the study, increasing the number of particles that reach the lymph nodes allows for a reduction in the overall dosage required to achieve robust immunity.

The Crucial Role of Lymph Nodes in Immune Priming

Lymph nodes serve as essential hubs where the immune system is taught to recognize and combat foreign pathogens. When a vaccine is administered, specialized cells must carry antigens to these nodes to instruct other immune cells on what to attack. While current mRNA vaccines have been remarkably effective, a significant portion of the dose often ends up in the liver rather than these vital immune centers. Hannah Yamagata, the study's first author, notes that by making this delivery process more precise, medical providers can ensure that more of the genetic cargo reaches the specific tissues responsible for long-term protection.

Integrating Aromatic Rings and Bioreducible Bonds

The research team developed a library of new lipids by incorporating benzene rings, a stable chemical structure that influences how molecules interact with cellular membranes. This marks the first time that aromatic rings have been combined with bioreducible disulfide bonds within lipid nanoparticles. These chemical linkages are designed to break apart once inside a cell, which enhances the release of the mRNA and reduces the potential for cellular toxicity. This dual-action design allowed the Penn team to subtly shift the physical behavior of the nanoparticles without compromising their structural integrity during transit.