Monitoring pH-induced lipid dynamics in mRNA-lipid nanoparticles by synchrotron small-angle X-ray scattering
Ke-Meng Li1, Panqi Song2, Zi-Ru Ye3
1Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Rd, Shanghai 200237, China; National Facility for Protein Science Shanghai, Shanghai Advanced Research Institute, No.333, Haike Road, Shanghai, Shanghai 201210, China.
Synchrotron small-angle X-ray scattering (SR-SAXS) reveals lipid nanoparticle (LNP) structural changes during pH shifts. This method aids in designing better nucleic acid therapeutics by understanding LNP dynamics.
Area of Science:
- Nanomedicine
- Biophysics
- Materials Science
Background:
- Lipid nanoparticles (LNPs) are promising drug delivery systems but their assembly and intracellular behavior remain poorly understood.
- Conventional characterization methods cannot capture dynamic mesoscopic structural changes of LNPs under varying pH conditions.
Purpose of the Study:
- To employ synchrotron small-angle X-ray scattering (SR-SAXS) for monitoring the dynamic self-assembly of mRNA-encapsulated LNPs at different pH levels.
- To elucidate the structural evolution of LNPs during pH transitions relevant to physiological environments.
Main Methods:
- Time-resolved SR-SAXS was used to monitor mRNA-LNPs during dialysis across a pH gradient (pH 7 to pH 4).
- Cryo-transmission electron microscopy (cryo-TEM) was used for cross-validation.
- Scattering profiles were fitted using a core-triple shell model for structural parameter extraction.
- Cell transfection experiments assessed the efficiency of different LNPs.
Main Results:
- SR-SAXS successfully captured dynamic structural transitions of LNPs from neutral to acidic pH.
- Structural parameters of LNPs formed with FDA-approved lipids (ALC-0315, DLin-MC3-DMA, SM-102) were determined.
- MC3-based LNPs exhibited the highest cellular transfection efficiency, correlating with their ability to form inverted hexagonal phases (HII).
Conclusions:
- SR-SAXS is a valuable tool for studying mRNA-LNP structural dynamics under pH gradients.
- Understanding LNP structural evolution aids in the rational design of nucleic acid therapeutics.
- This study expands the application of SAXS in nanomedicine discovery.
