Microfluidic synthesis of lipid nanoparticles has become a transformative method because it enables precise tuning of critical LNP attributes while using microliter-scale volumes. By tightly controlling mixing conditions, this approach allows systematic optimization of particle size, encapsulation efficiency, and overall formulation quality.
In microfluidic LNP synthesis, a lipid solution in ethanol is rapidly mixed with an aqueous phase containing the active pharmaceutical ingredient. The resulting drop in ethanol concentration reduces lipid solubility and drives LNP self‑assembly.
Among available production methods, microfluidics is a common approach to lipid nanoparticle formulation, offering precise control of LNP characteristics across both very low and larger volumes, making it a powerful tool throughout RNA–LNP therapeutic development.
Read on for answers to frequently asked questions about using microfluidics to formulate lipid nanoparticles.
A: RNA-LNPs are nanoparticles that contain phospholipids designed to encapsulate and deliver RNA molecules and other nucleic acids. LNPs are typically composed of an ionizable lipids, a helper phospholipid, cholesterol, and a PEGylated lipid.
RNA-LNPs protect nucleic acids from degradation and can be used to target uptake in specific cell types.
A: Optimizing the composition of ingredients allows for:
A: RNA and lipid materials are costly, and developing optimal LNP formulations requires screening multiple formulations and processing conditions. Conducting reproducible, small-volume tests and achieving high total RNA encapsulation ratios provide the most cost‑effective screening approach. However, once a suitable condition is identified, scaling up to larger volumes for in vivo testing can be challenging.
The TAMARA RNA-LNP formulation platform allows for small ~200 µl screening tests and large ~20 mL In-Vivo production tests using a single machine with the same process and Microfluidic chip design, resulting in identical results.
A: The main factors that impact LNP characteristics are formulation (lipid types, RNA type and concentrations), flow rate ratio (FRR), total flow rate (TFR) and the style of the microfluidic chip (herringbone vs. baffled).
A: Encapsulation efficiency (EE%) is the percentage of RNA that is bound to the LNPs. Only encapsulated RNAs will be protected and delivered. Higher EE% results in a stronger therapeutic effect at the same dose.
A: Critical Quality Attributes (CQAs) include:
A: Microfluidic mixing is much more rapid and controlled, enabling excellent reproducibility. This yields smaller particles with lower polydispersity and higher encapsulation efficiency, achievable in very small batches and directly reproducible at in vivo production scales.
A: The precision pumps and microfluidic chips integrated into the TAMARA system provide highly controlled and reproducible production of LNPs across both very low screening volumes and the larger batch sizes required for in vivo studies.
Equally important to successful LNP manufacture is the downstream purification step. Efficient solvent removal is essential to meet safety, tolerability, and regulatory expectations, as well as to ensure stable LNP performance. Purification tools such as dialysis play a key role in this process by enabling controlled exchange of organic solvents with physiological or formulation buffers, thereby reducing residual solvent content while preserving particle integrity, size distribution, and encapsulation efficiency.
A: A microfluidic chip is a network of microchannels connected to external inlets and outlets, designed to control how fluids interact. Microfluidic systems consist of two core components: a microfluidic chip, where liquids interact, and a flow control system that drives fluid movement.
For LNP synthesis, chip geometry must promote efficient mixing. While PDMS is common in prototyping, its high adsorption and poor solvent compatibility limit its use; low‑adsorption thermoplastics such as COP or glass are preferred.
A: Particle sizes below 150 nm are generally considered sufficient for Cell Uptake, Stability, Encapsulation, Release and ability to Sterile Filter. Smaller sizes below 120 nm will circulate in the system longer and higher quantities will end-up in metabolic organs like the liver and spleen. Larger particles 120-150nm will have lower circulation and more will be retained in organs local to injection site.
A: Flow rate ratio can impact particle size, Polydispersity, and Encapsulation Efficiency.
A: Very small samples can be produced using microfluidic mixing, sometimes in the range of 50 µL. For analysis including particle size, encapsulation efficiency and cellular uptake, a batch of 200 µL is typically required.
A: The higher the Encapsulation Efficiency (EE%) the more RNA will be bioavailable. EE% greater than 80% are typically considered acceptable for pre-clinical development and greater than 90b formulation volumes.
Integrated microfluidic platforms for nanoparticle formulation provide a robust alternative and a more accessible starting point for teams new to this field. The TAMARA platform is a leading example, combining the advantages of microfluidic technology with an intuitive, highly efficient design.
Read more about its specifications and details here.