Bioluminescence

Beyond the Liver: How Liposomal LNPs Are Expanding the Reach of mRNA Delivery

Posted on by Simon Moe

Introduction

Lipid nanoparticles (LNPs) have transformed mRNA delivery. From COVID-19 vaccines to the first approved RNAi therapeutic, ONPATTRO (Patisiran), LNPs have proven their ability to ferry nucleic acid cargo into cells with speed and efficiency (Huang, 2019). Despite this transformation, most clinically deployed LNP formulations share a significant constraint: following intravenous administration, roughly 90% of the injected dose clears to the liver within an hour. If your target is a hepatocyte, that is hardly a hindrance. It’s a serious limitation if you need to reach the spleen, lymph nodes, pancreas or other extrahepatic tissues, all of which are organs of major interest in immunotherapy, vaccine development and metabolic disease research.

A new paper from Pieter Cullis’s laboratory at the University of British Columbia (UBC) offers a structural solution to that problem. Their design, termed a ‘liposomal LNP’, reengineers the architecture of the particle itself to achieve dramatically longer circulation lifetimes and improved transfection in tissues that standard formulations have largely missed.

What are Lipid Nanoparticles?

LNPs enable fast transfection of a wide variety of cells, facilitating the transport of mRNA, DNA and siRNA into cells to induce transient expression in a short period of time (mere hours for mRNA and one to two days for DNA). They are a powerful tool that rose to broad public awareness through their use in COVID-19 vaccines, which delivered spike protein mRNA as cargo. Beyond vaccines, LNPs have been applied therapeutically as the delivery vehicle for ONPATTRO, which treats polyneuropathy of hereditary transthyretin-mediated amyloidosis (Huang, 2019).

The most widely studied LNP formulation, such as the ONPATTRO-like composition, consists of four components: an ionizable lipid, a helper lipid, cholesterol and a PEG-lipid. At physiological pH, the ionizable lipid is neutral and resides in a hydrophobic oil-like core surrounded by a lipid monolayer. This structure is highly effective at transfecting hepatocytes, but its rapid hepatic clearance limits its utility for reaching other tissues.

A Structural Redesign: What Makes the Liposomal LNP Different

Standard ONPATTRO-like formulations have a lipid monolayer surrounding an oil droplet core. The UBC team’s publication reasoned that dramatically increasing the proportion of bilayer-forming lipids, specifically equimolar egg sphingomyelin (ESM) and cholesterol, could fundamentally change what the LNP looks like (Cheng, 2025).

The authors explored various bilayer-to-ionizable lipid molar ratios (RB/I) to see how they modified the structure of the particle. They found that an RB/I of 4 resulted in particles that transition to a true liposomal architecture consisting of a lipid bilayer enclosing an aqueous interior with a solid core suspended inside. Cryo-electron microscopy confirmed that approximately 84% of particles at this ratio adopt this bilayer structure, with the solid core occupying roughly 30% of the interior. LNP sizes across all tested ratios remained in the 40–60 nm range, confirming that the structural shift happens without meaningful changes in particle size.

Why the Structural Change in Liposomal LNP Affects Assembly and Delivery

The liposomal LNP exploits pH-driven structural transitions at both the assembly and delivery stages, explaining how a particle dominated by bilayer lipids can remain transfection-competent.

Assembly: When an ethanol-lipid mixture meets an acidic aqueous buffer (pH 4) containing mRNA, the positively charged ionizable lipid binds the negatively charged mRNA, forming a core complex. This complex acts as a nucleation point for the deposition of ESM/cholesterol bilayer lipid. As pH rises to 7.4 during formulation, ionizable lipids in the outer monolayer shift to a neutral form and migrate inward, expanding an oil droplet core. The mRNA dissociates from the oil core and resides in the aqueous interior where it is protected within the bilayer.

Delivery: After endocytosis, the acidic endosomal environment reverses this process. The ionizable lipids become positively charged again and migrate to the outer surface of the LNP, causing the solid mRNA-containing core to extrude outward from the liposomal bilayer. This positively charged protrusion interacts with the negatively charged endosomal membrane, triggering fusion and releasing the mRNA into the cytoplasm for translation. The authors describe this as a localized “warhead” mechanism—a structural consequence of the bilayer architecture, rather than a simple membrane-disruption event.

Exploring the Performance of the Liposomal LNP

The authors utilized NanoLuc® mRNA as a reporter payload throughout the study. From in vitro transfection efficiency to whole-animal imaging, it allowed the authors to detect differential expression that would have been difficult to detect with less sensitive reporters.

The performance of the Liposomal LNP tells a compelling story. In vitro, the RB/I = 4 formulation matched or exceeded the transfection potency of the ONPATTRO-like composition in Huh7 cells across a wide dose range, while also proving to be the most stable on the shelf. After 63 weeks at 4°C, it maintained greater than 80% mRNA encapsulation with less than 20% size increase, and produced the highest mRNA integrity and translatability of any tested ratio.

SPECT/CT imaging of whole animals with the Liposomal LNP showed a circulation half-life approximately 15-fold longer than the standard ONPATTRO-like formulation, a direct consequence of the bilayer exterior adsorbing roughly half the plasma protein load. This reduced exterior plasma protein load means less macrophage recognition, less clearance and more time in circulation to reach tissues beyond the liver. That improved lifetime in circulation translated into improved tissue access. Ex vivo organ analysis showed 50-fold greater luminescence in the spleen and 150-fold greater in the inguinal lymph node compared to the standard formulation. Meaningful signal was also detected in the pancreas, a tissue rarely reached through conventional LNP formulations. Immunofluorescence confirmed delivery was localized to macrophages at the marginal zone of the spleen and subcapsular sinus of the lymph node.

It is also worth noting that the liposomal morphology held up when tested with the ionizable lipids used in the BNT162b2 and the mRNA-1273 COVID vaccines, suggesting this is a generalizable design.

Expanding Use of NanoLuc® mRNA: UBC RNA and Formulation Core

Throughout this study, NanoLuc® mRNA served as the reporter payload. In vitro, NanoLuc® luminescence normalized to total protein provided a sensitive, linear measure of transfection efficiency across a wide dose range. In vivo, it enabled whole-animal IVIS imaging using the Nano-Glo® Fluorofurimazine substrate, with quantification extended to ex vivo organ homogenates using the Nano-Glo® Luciferase Assay System. NanoLuc® Luciferase sensitivity enabled detecting differential expression in tissues as small as inguinal lymph nodes and the pancreas. Detecting meaningful signal from a lymph node or pancreas can be challenging and thus successful detection demonstrates the exceptional performance of NanoLuc® Luciferase.

The authors synthesized their NanoLuc® mRNA in-house, a capability not universally available to research groups. We have partnered with the University of British Columbia RNA and Formulation Core to close that gap, enabling distribution of NanoLuc® mRNA across the core’s academic and industry network. Researchers who want to investigate LNP delivery, optimize formulations or validate mRNA constructs can now work with the RNA and Formulation Core to acquire NanoLuc® mRNA without the overhead of in-house synthesis. Work from UBC has contributed foundational understanding for LNP formulations, and now through their core they enable NanoLuc® mRNA development for any interested scientist.

Conclusion

The work from UBC demonstrates what becomes possible when mRNA delivery can reach beyond the liver, but the findings are only useful if researchers can access the tools to replicate and build on them. That’s where the UBC RNA and Formulation Core comes in. By partnering with Promega to distribute NanoLuc® mRNA, the Core gives researchers direct access to the same reporter used in this study, without the overhead of in-house synthesis. Whether you’re optimizing an LNP formulation, validating extrahepatic delivery or exploring mRNA constructs for a new application, you can now work with the Core to get started.

Interested in learning more about the UBC RNA and Formulation Core? Explore their website.

Learn more about the full NanoLuc® portfolio.

Citations

Cheng, M.H.Y. et al. (2025) Liposomal lipid nanoparticles for extrahepatic delivery of mRNA. Nature Communications 16, 4135.
Huang, Y.Y. (2019) Approval of the first-ever RNAi therapeutics and its technological development history. Prog. Biochem. Biophys. 46, 313–322.

Stolen Chloroplasts and the Chrysalis of Complex Life 

Posted on by Elise Johnson

Despite its many mysteries, a chrysalis is one of the most familiar transformations in nature. We know what goes in. We know what comes out. For a long time, what happened in between was essentially invisible to us. Not because we weren’t curious, but because the mechanism was sealed inside something the size of a thumbnail, and we had no way in.

This same invisibility exists on a much older and much larger scale.

Sometime around two billion years ago, a cell swallowed a bacterium and, instead of digesting it, kept it alive inside itself. This process, called endosymbiosis, is arguably the single most consequential event in the history of complex life. The bacterium became a permanent resident, and over billions of years of co-evolution, it became something else entirely: the mitochondria that power every complex cell on earth. Without it, the living world as we know it doesn’t exist.

Scientists have known for decades that this kind of cellular acquisition had to have occurred. What has proved harder to explain is not that it happened, but how it started. What did the earliest molecular steps actually look like from the inside?

In the ocean, there is a microscopic single-celled organism called Rapaza viridis. It hunts algae by propelling itself through the water on whip-like appendages called flagella. That hunt may be showing us the beginning of a modern endosymbiosis: the same process that gave every complex cell its mitochondria and every plant its chloroplasts.

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Detecting Neuroinflammation in Microglia and Astrocytes

Posted on by Simon Moe

The brain is one of the most complex and fascinating parts of biology. Thankfully, it’s also remarkably good at protecting itself. When exposed to a pathogen, an injury or even misfolded proteins, microglia and astrocytes function as the central nervous system’s (CNS) primary immune defenders. They mount an inflammatory response by releasing cytokines and working to contain the damage. Yet this same system can malfunction or not resolve, which manifests as devastating consequences.

Chronic neuroinflammation is now recognized as a shared characteristic across some of the most common and difficult-to-treat neurological conditions. A 2023 review in Signal Transduction and Targeted Therapy highlighted the dualistic nature of neuroinflammation: while acute responses serve a protective role, chronic or dysregulated inflammatory signaling can initiate and accelerate neurodegeneration, identifying these pathways as priority targets for therapeutic intervention (Zhang et al., 2023). A 2025 review in Science reinforced this view, noting that within Multiple Sclerosis, disease-modifying therapies targeting neuroinflammation have seen the most clinical success (Shi & Yong, 2025). This could suggest applications within neurological conditions where the same inflammatory mechanisms are at work.

Understanding how and where these inflammatory signals originate in the CNS is an active area of preclinical research. One cytokine being actively studied is IL-6. IL-6 is produced by several cell types, including astrocytes and microglia in the CNS. As a key mediator of inflammatory responses, it mediates pro-inflammatory effects through its trans-signaling, which occurs via soluble IL-6 receptors. Dysregulation of this mechanism may contribute to the chronic neuroinflammation seen in several neurological conditions. Characterizing how and when IL-6 is secreted from CNS cells is an important step toward understanding the neuroinflammatory processes underlying these disorders.

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Light Has a Favorite Color, But It’s Complicated

Posted on by Elise Johnson

Last spring, my niece and I made a trip to a home improvement store to put together a Mother’s Day planter for my sister. My niece had a clear vision: my sister’s favorite color is blue, so we were going to buy blue flowers. We walked every aisle of the garden center. We checked the annuals, the perennials, and the hanging baskets then left with purple, red, and a grumpy 7-year-old.

It turns out we were not up against a bad selection. We were up against biology.

The Problem with Blue

Blue is one of the rarest colors in the natural world. The food industry is currently finding that out the hard way. There is a good chance you have eaten something blue today. Maybe it was the frosting on a birthday cake, the coating on some M&M’s® candies, or the sports drink in your refrigerator. That blue almost certainly came from a petroleum-based synthetic dye, and for the first time in decades, the food industry is being asked to find something better.

The FDA banned Red Dye No. 3 in January 2025, and pressure has been building around the remaining synthetic dyes ever since, including Blue No. 1 and Blue No. 2. Major food brands have begun announcing plans to reformulate.

There is just one problem. Blue is genuinely, stubbornly hard to make in nature. It turns out that blue has almost nothing to do with color, and almost everything to do with light.

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Why BRETSA™ Target Engagement Matters for Drug Discovery

Posted on by Michele Arduengo, PhD

Drug discovery researchers face a fundamental constraint in their work to develop safe, effective therapeutics: the vast majority of the human proteome remains inaccessible to conventional small molecule approaches. Proteins without defined binding pockets, those lacking known chemical probes, and protein targets that fail to translate from biochemical assays into cellular models have long been considered out of reach of standard drug discovery screening tools. As Dixit et al. describe, developing biochemical or cellular assays for all genome-encoded targets “is not scalable and likely impossible as most proteins have ill-defined or unknown activity” — these are what the authors call “the dark undruggable expanses” of the proteome [1].

That gap is now narrowing. Promega Corporation recently launched the TarSeer™ BRETSA™ Target Engagement System, a live-cell target engagement platform designed to bring previously challenging targets within reach of early-stage drug discovery.

The Problem: A Translation Gap in Early Discovery

Drug discovery teams regularly encounter a frustrating disconnect. A compound may show strong binding activity in a biochemical assay, only to fail when tested in a cellular environment. Without target-specific cellular assays, which generally aren’t available for poorly characterized proteins, researchers face difficult choices when deciding which compounds to advance through the drug development pipeline.

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Trends and Tools Transforming Drug Discovery: Five Takeaways from Discover Glo 2025

Posted on by Meghan Rollins

In biologics, cell therapy, and targeted protein degradation, the science is moving fast—and so are the tools. From GPCR-targeted therapies to real-time CAR-T manufacturing tools, new techniques are reshaping how scientists approach drug development, live-cell imaging, and protein degradation.

The “Bringing Light to Science” Discover Glo 2025 speaker series brought together researchers from across academia and industry to share real-world examples of how bioluminescent technologies are helping them advance their research. Now available on demand, these sessions offer fresh perspectives and actionable takeaways on the future of therapeutic development, cellular analysis and assay design.

We’ve distilled five key takeaways from the sessions—practical insights you can apply to your own work or use to stay current with where the field is heading.

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A New View of Protein Degradation with HiBiT and Live Cell Imaging

Posted on by Anna Bennett

Targeted protein degradation (TPD) is an emerging drug discovery strategy that offers an entirely different approach to tackle disease-relevant proteins, including classic “undruggable” targets. Instead of inhibiting protein function, small molecules like PROTACs and molecular glues co-opt the cell’s own ubiquitin-proteasome system to eliminate specific proteins altogether. But as this targeted approach gains traction, it also challenges existing methods for validating compound activity.  

How do you confirm that degradation is happening in a biologically-relevant system? Can you validate protein degradation in real-time?  

Continue reading “A New View of Protein Degradation with HiBiT and Live Cell Imaging”

Understanding Wnt Signaling Through β-Catenin Localization in Live Cells

Posted on by Anna Bennett

The Wnt/β-catenin pathway, long studied in the context of developmental biology, has become increasingly recognized for its role in a wide range of human diseases. Its dysregulation has been implicated in cancer, fibrosis, immune modulation, and neurodegenerative conditions—making it a clinically actionable target across diverse therapeutic areas1. In this blog, we cover the fundamentals of Wnt/β-catenin signaling, highlight ongoing research efforts to understand its role in disease, and show how combining live-cell imaging with luminescent assays complements functional studies.

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Using Dual-Luciferase Assays to Identify the Role of Non-Coding RNAs in Disease

Posted on by Michele Arduengo, PhD

In recent years, non-coding RNAs—especially microRNAs (miRNAs) and long non-coding RNAs (lncRNAs)—have emerged as powerful regulators of cellular behavior. These molecules modulate gene expression, often by targeting mRNAs for translational suppression or degradation. Two recent studies—one focused on osteoarthritis and the other on 5-Fu-resistant colorectal cancer—illustrate how these non-coding, regulatory RNAs operate within disease-relevant signaling networks, providing new points for therapeutic intervention.

lncRNA, long noncoding RNA

Both studies use the pmirGLO Dual-Luciferase miRNA Target Expression Vector to evaluation predicted miRNA activity.  This dual-luciferase system offers a clean and quantifiable way to validate miRNA–mRNA interactions using a simple bioluminescent readout. By cloning the 3´ untranslated regions (UTRs) of suspected targets downstream of a firefly luciferase reporter and normalizing against Renilla luciferase, researchers can rapidly confirm whether a miRNA directly regulates its target.

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Bioluminescence vs. Fluorescence: Choosing the Right Assay for Your Experiment 

Posted on by Anna Bennett

From enzyme activity to gene expression, light-based assays have become foundational tools in life science research. Among these, fluorescence and bioluminescence are two of the most widely-used approaches for detecting and quantifying biological events. Both rely on the emission of light, but the mechanisms generating that light—and the practical implications for experimental design—are quite different. 

Choosing between a fluorescence or bioluminescence assay isn’t as simple as picking between two reagents off the shelf. Each has strengths and limitations depending on the application, instrumentation, and biological system. In this blog, we’ll walk through how each method works, where they shine (and where they don’t), and what to consider when deciding which approach is right for your experiment. 

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