In 2021, billions of people received an injection that worked differently from any vaccine before it. Instead of a weakened pathogen or a protein fragment, it contained a genetic instruction, a short strand of mRNA encoding the spike protein of SARS-CoV-2. The immune system read the instruction, built the protein, learned to recognize it, and was ready. The mRNA itself was gone within days. What made the whole thing possible was not the genetic sequence. It was the tiny lipid shell that carried it safely to the right place.
That shell was a lipid nanoparticle. And while most people experienced it as a vaccine, the underlying technology had been in development for decades and is now being applied to some of the most ambitious problems in modern medicine: silencing disease-causing genes, delivering cancer therapies, and beginning to make in vivo (i. e. within the living organism) gene editing a clinical reality.
LIPID NANOPARTICLES FOR GENE DELIVERY
Genetic material is extraordinarily fragile in the human body. A strand of mRNA or siRNA, introduced into the bloodstream without protection, survives for seconds. Enzymes called nucleases degrade it almost immediately. What survives the bloodstream still has to cross the cell membrane, a fatty barrier that blocks large, charged molecules by design. And even if a molecule reaches the inside of a cell, it may end up trapped in an endosome, a compartment the cell uses to break down foreign material, never reaching the cytoplasm where it needs to work.
Lipid nanoparticles solve all three problems in sequence. They encapsulate the genetic payload during transit, protecting it from nucleases, just like a normal plasmid nanoparticle would do Their lipid surface allows them to fuse with or be absorbed by cell membranes far more efficiently than a naked nucleic acid strand. And once inside the endosome, a specific class of lipids responds to the acidic environment, disrupts the endosomal membrane, and releases the payload into the cytoplasm where it can function.
This last step, called endosomal escape, is what separates modern lipid nanoparticles from earlier liposome-based systems. Liposomes, which have been used since the 1990s to deliver conventional drugs, are mostly passive carriers. LNPs are active ones. The difference is in their composition and the specific design of the lipids that drive intracellular delivery.
The clearest proof that this works at scale is Onpattro, approved by the FDA in 2018 as the first siRNA therapy to reach the market. It treats hereditary transthyretin-mediated amyloidosis, a rare genetic disease in which a misfolded protein accumulates in peripheral nerves and organs, causing progressive and eventually fatal damage. The LNP in Onpattro carries small interfering RNA that silences the gene responsible for producing the aberrant protein in liver cells. Once the gene is silenced, production stops, levels fall, and the disease progression slows. The drug does not repair the gene. It simply turns down the volume, precisely and sustainably, using a lipid carrier as the delivery mechanism.
HOW TO MAKE LIPID NANOPARTICLES
A lipid nanoparticle is made of four components, each with a specific role, combined through a process that is simple in principle and demanding in practice.
The first component is the ionizable lipid, the most critical and most carefully engineered element. It carries a positive charge at low pH, which allows it to bind tightly to the negatively charged nucleic acid payload during formulation. At physiological pH, in the bloodstream, it becomes electrically neutral, which is important: a permanently charged particle would attract proteins, be cleared quickly, and trigger immune responses. In the acidic environment of the endosome, the ionizable lipid becomes charged again, destabilizing the endosomal membrane and releasing the payload. ALC-0315, the ionizable lipid in the Pfizer-BioNTech COVID-19 vaccine, and SM-102, used in Moderna’s formulation, were the result of years of iterative design to optimize this pH-sensitive switching behavior.
The second component is a structural phospholipid, typically DSPC (distearoylphosphatidylcholine), which helps stabilize the particle and contributes to the integrity of the lipid shell. The third is cholesterol, which fills gaps between lipid molecules, reduces membrane permeability, and improves particle stability, much as it does in natural cell membranes. The fourth is a PEG-lipid, a molecule with a polyethylene glycol chain attached to a lipid anchor. The PEG layer creates a hydrophilic shield around the particle, preventing it from aggregating and slowing its clearance by the immune system. Without PEG, particles would clump and be eliminated before reaching their target.
The manufacturing process mixes these four lipids, dissolved in ethanol, with an aqueous solution containing the nucleic acid payload. When the two streams meet under controlled conditions, the lipids spontaneously self-assemble around the genetic cargo, forming particles of 70 to 100 nanometres. The ratio of components, the flow rates, the temperature, and the mixing speed all affect particle size, encapsulation efficiency, and ultimately how well the product works. Scaling this process from a laboratory bench to industrial production while maintaining consistency across millions of doses was one of the major engineering challenges of the COVID-19 vaccine rollout. Early formulations required storage at minus 70 degrees Celsius because the mRNA was less stable and the particles less robust. Reformulated versions and improved lipid combinations have since extended stability at standard refrigerator temperatures, a critical improvement for distribution in regions without cold-chain infrastructure.
LIPID NANOPARTICLES FOR DRUG DELIVERY
The gene delivery applications attract the most attention, but lipid nanoparticles are also reshaping how conventional drugs and more complex biologics reach their targets.
In oncology, LNPs offer a way to concentrate a drug in tumour tissue while limiting exposure in healthy organs. Tumour vasculature is often poorly formed and leaky, which allows nanoparticles to accumulate there more than in normal tissue. By loading a chemotherapy agent into an LNP, it is possible to achieve higher concentrations at the tumour site while reducing the side effects that have historically made cancer treatment so debilitating. This is the same principle that made Doxil, the liposomal doxorubicin formulation approved in 1995, a clinical milestone: encapsulation changed where the drug went and how much damage it caused along the way. Modern LNPs take this further by enabling active targeting, where ligands on the particle surface recognize specific receptors on cancer cells and guide the particle to the right address.
For small molecule drugs with poor solubility, LNPs can dramatically improve bioavailability by keeping the active compound in a dispersed, absorbable form rather than letting it precipitate. For protein-based drugs and peptides, which are typically degraded too quickly to be effective when taken orally, LNPs offer a path toward formulations that protect the molecule through the digestive tract or allow for localized injectable delivery.
The most significant frontier, however, is the combination of LNPs with gene editing tools. CRISPR-Cas9, the molecular scissors that can cut and modify specific DNA sequences, requires delivery of both a protein and a guide RNA into the nucleus of a target cell. LNPs are now being used in early clinical trials to deliver these components in vivo, directly into the body, without the viral vectors that earlier gene therapy approaches depended on. Intellia Therapeutics has reported clinical data for an LNP-delivered in vivo CRISPR therapy targeting the same transthyretin gene as Onpattro, this time editing the gene directly rather than silencing it. If these approaches succeed at scale, LNPs will have become the platform not just for delivering messages to cells, but for rewriting them.
WHERE THIS IS HEADING
Regulatory frameworks are developing alongside the technology. The EMA and FDA have established specific guidance pathways for advanced therapy medicinal products (ATMPs) and for mRNA-based medicines, recognizing that the carrier is as important as the payload in determining a product’s safety and efficacy profile. The COVID-19 vaccines accelerated this process: regulators gained substantial experience reviewing LNP-based products under pressure, and that experience is now feeding into clearer, faster pathways for the next generation of LNP therapies.
The research community is working on organ-specific targeting: today’s LNPs, administered intravenously, tend to accumulate in the liver because of how the organ filters blood. For many gene therapy applications this is useful, since many genetic diseases affect the liver. But reaching the lungs, muscle, or the central nervous system requires modifying the lipid composition and surface chemistry to redirect the particle’s biodistribution. Early results from academic and industry groups suggest this is achievable through selective organ targeting (SORT) approaches, where changing the ratio or identity of the lipid components shifts where the particles end up.
Nanomnia follows these developments from the encapsulation side of the equation. The formulation principles that govern an LNP, how lipid composition controls release, how particle size affects tissue penetration, how surface chemistry determines biological fate, are the same principles that apply across the sectors Nanomnia works in, from pharmaceutical delivery to nutraceutical bioavailability. The sophistication of gene delivery is pushing the whole field of encapsulation science forward, and those advances translate.
CONCLUSION
The lipid nanoparticle did not appear fully formed with the COVID-19 pandemic. It was the product of three decades of lipid chemistry, formulation science, and incremental clinical development, much of it invisible to anyone outside the field. Onpattro proved the gene silencing concept in 2018. The vaccines proved it at global scale in 2021. CRISPR delivery is taking the same platform toward something that would have been considered science fiction not long ago: editing the genome of living patients without removing a single cell from the body.
The four components of an LNP look simple on a list. The science behind each one, and the engineering required to combine them reliably at scale, is not. What the lipid nanoparticle demonstrates, again, is that the carrier is not an unimportant detail. It is actually the core of the technology itself.