Real-Time Monitoring of Lipid Nanoparticle (LNPs) Production Using In-Line Dynamic Light Scattering (DLS)
Background
The large-scale manufacturing of nanomedicines continues to be a major hurdle in their successful translation from laboratory research to clinical application. Despite promising therapeutic potential, many nano-based drug delivery systems fail to progress beyond the preclinical stage due to limitations in scalability, batch-to-batch consistency, and regulatory compliance.
Microfluidic technologies have recently emerged as a leading platform for the controlled and reproducible synthesis of these nanoparticles. Their inherent advantages—including precise control over fluid dynamics, rapid mixing, and the potential for continuous production—make microfluidics particularly well-suited for the scalable fabrication of nanomedicines.
Objective
In this context, the objective was to develop a robust and efficient microfluidic-based process for the production of lipid nanoparticles (LNPs), which are widely recognized for their effectiveness in nucleic acid delivery and their recent success in mRNA vaccine formulations. To generate stable and monodisperse LNPs using a high-speed microfluidic mixing system, real-time process control and product consistency, an innovative in-line size monitoring device based on Dynamic Light Scattering (DLS) was used, enabling continuous feedback on particle size distribution during production.
Experimental Setup
DLS allows for the measurement of nanoparticle size and, the use of this on-line method allows for real-time monitoring of nanoparticle size as the suspension elutes from the microfluidic cell. DLS measurements were performed with a Cordouan Vasco Kin configured with an in-line head for direct measurement on the effluent suspension produced by the microfluidic synthesis system. The setup of the synthesis and DLS system is shown in Figure 1.
Figure 1. (A) Schematic representation of the microfluidic system designed for lipid nanoparticle (LNP) synthesis. (B) Efficient and rapid mixing of lipid and aqueous phases is performed through a herringbone-patterned microfluidic mixing chip, (C) an in-line Dynamic Light Scattering (DLS) probe is inserted downstream of the mixing chip to enable continuous monitoring of nanoparticle size during synthesis. (D) the nanoparticle suspension flows through a millifluidic DLS detection unit consisting of a transparent glass capillary for real-time, non-invasive particle size analysis without interrupting the production process.
Real-Time Monitoring Results
A critical aspect of LNP efficacy is the size distribution of the LNPs – sizes that are too large, too small, or not distributed properly will not perform in vivo as desired. Through the use of the online DLS system, the size (and scattering intensity) may be observed as the synthesis is performed (Figure 2). This approach enables immediate detection of variations in particle formation and provides the opportunity for real-time process adjustments during production.
Figure 2: Real-time monitoring of particle size and intensity during cyclic variations in synthesis conditions, with each cycle lasting 40 seconds. The data demonstrates the system’s ability to detect and track dynamic changes in nanoparticle characteristics throughout the production process.
CONCLUSIONS
In this study, the feasibility of in-line, real-time monitoring of lipid nanoparticle (LNP) physical characteristics was demonstrated during their synthesis process. By integrating an in-line dynamic light scattering (DLS) probe directly into the production line, it was possible to continuously assess parameters such as particle size and polydispersity without interrupting the flow or requiring offline sampling.
This represents a significant advancement toward the real-time process analytical technology (PAT) framework for LNP formulation, enabling better control, reproducibility, and optimization of nanoparticle production. The system reduces offline sampling time, minimizes batch failures, and enables immediate process adjustments—ultimately accelerating the path from laboratory research to clinical application for nanomedicine platforms.
Steve’s Solutions
This Steve’s Solution was written based on the following work: A. Nsamela et al., SFNano Annual Meeting, December 2022. For more details on this presentation, please contact us.
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