Lipid Nanoparticle Synthesis Pack

Applications of RNA-LNP:

Thanks to their flexibility, RNA-LNP can be used for a wide range of vaccines and therapeutics applications

1. RNA Vaccines for Infectious Diseases

RNA-LNP technology is widely used to develop vaccines that generate strong immune responses against infectious diseases. By delivering mRNA encoding a disease-specific antigen , (viral or bacterial protein) the immune system is trained to recognize and combat the actual pathogen.

This approach showed its potential with the COVID-19 mRNA vaccine but can also be used for other infectious diseases such as Malaria, HIV… While mRNA is the most common payload, other RNA types like self-amplifying RNA (saRNA) and circular RNA (circRNA) are also being explored to enhance efficacy and stability.

2. Personalized Cancer Vaccines

By delivering tumor-specific RNA sequences that encode neoantigens, RNA-LNPs can prime the immune system to recognize and eliminate cancer cells . This personalized approach is tailored to the unique mutation profile of each patient’s tumor, opening the door to highly targeted immunotherapies.

3. Gene Therapy

RNA-LNPs are increasingly used to deliver therapeutic RNA into cells to treat genetic disorders. This includes two key therapeutic strategies:

• mRNA-Based and siRNA Therapies

These approaches are designed for transient protein expression or temporary gene silencing , making them ideal for conditions where short-term therapeutic effects are sufficient. A prominent example is in vivo CAR-T therapy in oncology, where mRNA-LNPs deliver genetic instructions for chimeric antigen receptor (CAR) expression directly in the patient’s T cells. In this context, gene delivery remains a critical challenge, primarily due to the liver tropism of lipid nanoparticles. Overcoming this barrier often involves surface functionalization of lipid nanoparticles to improve targeting specificity. 

Another example is Onpattro® (patisiran) by Alnylam, a siRNA-LNP based therapy that targets and silences the mRNA responsible for producing abnormal transthyretin (TTR) protein in hereditary transthyretin-mediated amyloidosis (hATTR).

• Genome Editing with RNA-LNPs

LNPs are also used to deliver CRIPSR-CAS9 components for permanent gene correction, offering a safer, non-viral alternative to traditional RNA delivery methods such as electroporation or lentivirus. This approach holds promises for treating monogenic diseases at their root cause. Additionally, RNA-LNPs can be adapted to deliver antisense oligonucleotides and other gene-silencing tools to precisely regulate gene expression.

Check out our recent review to know more about CRISPR-CAS9 and its relationship with microfluidics !  

This list is not exhaustive. As this field is very active, there are many other applications.

Remaining challenges in RNA-LNP – where can microfluidics help?

RNA-LNP therapeutics and vaccines have revolutionized modern medicine, yet several key challenges remain before their full potential can be realized. Beyond achieving therapeutic efficacy, enhancing stability, immunogenicity, and extra hepatic delivery are central to advancing next-generation RNA therapeutics. Current efforts focus on three major areas:

1.Targeted Delivery and Biodistribution Control One of the most pressing challenges is improving biodistribution , where and how the LNPs travel and accumulate in the body. Current LNPs show a strong liver tropism , which is not always ideal for vaccines or non-hepatic diseases. Improved biodistribution enhances therapeutic efficacy and safety, especially in systemic applications and repeated dosing scenarios. Improved targeting can be achieved using two different approaches, passive and active targeting:

• Passive targeting This approach relies on optimizing the physicochemical properties of LNPs (particle size, surface charge, lipid concentration and lipid composition) to influence biodistribution. This approach allows for more target RNA delivery to target organs and cells. In this context, microfluidics offers a unique advantage, enabling the efficient screening of multiple RNA-LNP formulations at very low volumes, accelerating the identification of optimal formulations while minimizing the costs.
  
  
• Active targeting Active targeting involves functionalizing LNPs with ligands that bind to specific cell-surface receptors (eg, dendritic cells, T cells, or tumor cells). This strategy enables precise delivery of RNA payloads to the desired cell types. Again, microfluidics can play a critical role here by providing precise control over LNP surface modification and enabling reproducible ligand incorporation.
  

For more information on this topic, see the detailed review of RNA-LNP active and passive targeting techniques from InsideTx. 

2.Mitigating PEG Immunogenicity and Improving Repeat Dosing PEGylation is commonly used to prolong LNP circulation time, but it also poses risks. Anti-PEG antibodies can develop, reducing efficacy upon re-administration and increasing the risk of hypersensitivity reactions. Alternatives such as PEG substitutes , biodegradable polymers , or zwitterionic coatings are under investigation to preserve stealth properties while minimizing immune responses.

3.RNA-LNP vaccine stability The cold chain requirement for mRNA vaccines is a major barrier to global distribution. In a first step, adjusting the lipid mix can significantly enhance the thermal and chemical stability of RNA-LNPs. This involves screening large libraries of lipid combinations, an area where microfluidics excels , thanks to its ability to test hundreds of compositions using minimal sample volumes. Other approaches such as lyophilization , or freeze-drying, can stabilize RNA-LNPs for storage at room or refrigerator temperatures. However, maintaining nanoparticle structure and RNA integrity during rehydration is complex. 

From oncology to immunity and rare disease treatment, RNA-LNPs are transforming what’s possible in drug development. Whatever your application, the Elveflow and InsideTx teams are here to help, feel free to reach out to us to discuss your project.

Controlling RNA-LNP size with microfluidics 

Nanoparticle size is one of the most critical characteristics, influencing biodistribution , cellular uptake , and overall therapeutic performance . The size of the LNPs is primarily governed by the mixing speed between the solvent and aqueous phase triggering the LNP formation. Faster microfluidic mixing leads to smaller particles, while slower mixing results in larger ones, as illustrated in the below graph.

Influence of mixing speed and conditions on RNA-LNP size

To achieve precise and tunable size control, microfluidic devices typically incorporate efficient microfluidic mixing structures, such as baffle and herringbone micromixer , two of the most popular microfluidic chaotic mixers. These micromixers allow users to control nanoparticle size by simply tuning the TFR ( Total Flow Rate , or sum of the aqueous and solvent flow rates ), making size optimization intuitive and repeatable.

Furthermore, FRR (Flow Rate Ratio, or the ratio of the aqueous flow rate over the solvent flow rate) can also be tuned to further control the nanoparticle characteristics. 

Illustration and image under a microscope of a baffle and a herringbone microfluidic mixers used for RNA-LNP formulation.

In practice, the graph below illustrates the impact of the formulation conditions on nanoparticle characteristics. It can be noticed that both the lipid composition and the formulation parameters (here the TFR) greatly impact the nanoparticle size, reinforcing the importance of the high level of control offered by microfluidics.

Influence of TFR and composition on LNP size and PDI in a Herringbone microfluidic mixer

Beyond Size: The Importance of Formulation Screening

While size is critical, other formulation parameters, such as lipid ratios , ionizable lipid choice, and process conditions, have a direct impact on other Critical Quality Attributes (CQAs) like encapsulation efficiency, morphology , and in vivo performance . This complexity underscores the importance of screening a wide range of formulation conditions, particularly during early phase development. This is precisely where microfluidics excels , enabling the efficient production and testing of numerous RNA-LNP formulations at ultra-low volumes, accelerating development while minimizing the use of expensive RNA material.

Practical approach to RNA-LNP synthesis

One of the greatest strengths of microfluidic systems is their adaptability. The same microfluidic platform can be used to produce a wide array of nanoparticle types, from liposomes to complex RNA-LNP formulations, across a broad range of working volumes. This flexibility makes microfluidics ideal not only for screening and optimization but also for producing material for preclinical animal studies.

In practice, microfluidic formulation systems can be deployed in two main ways: homemade system, such as the LNP pack, a custom system including the OB1 pressure controller and flow sensors from Elveflow, and more integrated platform, such as TAMARA from Inside Terapeutics:

LNP Pack (Homemade/custom system)	TAMARA (Integrated microfluidic system)
✅	✅
Monodispersed nanoparticle formulation Customizable setup: automation compatible Reusable chips	Extremely user-friendly — suitable for all experience levels Monodispersed nanoparticle formulation Quick setup and operation (up to 20 formulations/hour) Broader working volume range (µL and mL) Improved control and repeatability Zero formulation losses Reusable chips
❌	❌
Complex setup, not beginner-friendly Longer run time Steep learning curve Limited microfluidic efficiency (minimum formulation volume ~1 mL) Lower reproducibility High formulation losses (300 µL minimum)	Less customizable for full automation workflows