Engineers at the University of Pennsylvania have introduced two distinct advancements in lipid nanoparticle (LNP) technology. One development is LIBRIS, an automated microfluidic platform designed to accelerate the formulation of LNPs, aiming to generate extensive data for training artificial intelligence (AI) models. Concurrently, another team has engineered modified LNPs, referred to as "aroLNPs," to enhance the precision of mRNA delivery by directing particles towards lymph nodes and reducing uptake in the liver. Both innovations contribute to the ongoing development of mRNA-based therapies.
Accelerated LNP Design with LIBRIS Platform
Engineers at the University of Pennsylvania have developed LIBRIS (LIpid nanoparticle Batch production via Robotically Integrated Screening), an automated microfluidic platform. This system is designed to generate lipid nanoparticle (LNP) formulations at an accelerated rate, with the goal of providing data necessary for training predictive AI models.
The design of LNPs, which are used in mRNA therapies, is complex due to the varying ratios of lipid components that influence genetic delivery.
A challenge has been the limited data available to link chemical inputs to biological outcomes, hindering AI integration.
Existing LNP formulation methods are often slow, serial, and require cleaning between runs, typically producing tens to hundreds of particle designs per hour.
LIBRIS addresses these limitations by utilizing a robotic platform with parallel microfluidic channels, enabling the simultaneous creation of up to eight distinct LNP formulations. The system can produce approximately 1,000 LNP formulations per hour, marking about a 100-fold increase compared to manual microfluidic methods. This platform is expected to accelerate LNP development by generating large LNP libraries, providing datasets for AI models to identify patterns between chemical structure and biological effect. The long-term objective is to facilitate the "rational design" of LNPs, allowing for the specification of desired particle properties. This study was published in ACS Nano, with contributions from Michael J. Mitchell and David Issadore as co-senior authors.
Enhanced LNP Targeting with aroLNPs
Penn Engineers have also redesigned a component of lipid nanoparticles (LNPs), the delivery vehicles for mRNA vaccines, to direct them towards lymph nodes and decrease off-target delivery to the liver. This modification aims to improve the efficiency of mRNA vaccines, potentially enabling strong immune protection at lower doses.
Michael J. Mitchell, an Associate Professor in Bioengineering (BE) and senior author of a study in the Journal of the American Chemical Society, noted that:
"Increased particle delivery to lymph nodes could lead to a reduction in the required dose."
The researchers modified the ionizable lipid, a key LNP ingredient, by incorporating an aromatic ring, leading to the designation "aroLNPs."
In animal models, aroLNPs delivered at least tenfold less mRNA to the liver compared to the LNP formulation used in the Moderna COVID-19 vaccine, while maintaining similar levels of lymph-node delivery. This resulted in a five- to tenfold increase in the lymph-node-to-liver delivery ratio. The redesigned aroLNPs also accumulated similarly in the lymph nodes.
The development of aroLNPs could also advance other mRNA therapies, including cancer vaccines and treatments for autoimmune diseases. Researchers indicated that more precise nanoparticle delivery offers increased control over immune activation.
Developing aroLNPs: Key Modifications
- Previous research suggested that an aromatic compound could improve LNP performance.
- The Penn team explored various aromatic structures by creating a library of ionizable lipids incorporating benzene rings, systematically adjusting the positioning of chemical groups.
- Bioreducible disulfide bonds, previously shown to enhance performance and reduce toxicity, were also included. Marshall Padilla, a postdoctoral fellow in BE and co-author, stated:
"This is the first known combination of aromatic rings and bioreducible disulfide bonds within lipid nanoparticles."
To evaluate the designs, luciferase mRNA, which produces a light-emitting protein, was packaged into the nanoparticles. By measuring the glow in different organs of animal models, researchers tracked the distribution of the genetic cargo. Hannah Yamagata, a doctoral student in BE and first author, observed a notable reduction in liver delivery.
The reduction in off-target nanoparticle delivery did not diminish the particles' ability to stimulate the immune system. In a vaccine model, aroLNPs generated antibody responses comparable to clinically approved formulations, with similar antibody levels. Furthermore, aroLNPs caused minimal increases in systemic proinflammatory cytokines, immune proteins associated with vaccine side effects such as fatigue and fever. Yamagata concluded that:
"The modified nanoparticles could lead to more precise, better tolerated, and more efficient vaccines."
Future applications include tailoring immune responses for specific conditions like cancer or autoimmune diseases.
This study was conducted at the University of Pennsylvania School of Engineering and Applied Science and received support from multiple U.S. National Science Foundation awards and other grants. Additional co-authors from Penn Engineering and Penn Medicine contributed to the study.