Liposomes and lipid nanoparticles: a tutorial for advanced chemical and structural characterisation

Area of Science:

• Nanomedicine
• Analytical Chemistry
• Materials Science

Background:

• Liposomes and lipid nanoparticles (LNPs) are crucial for drug delivery.
• Their complex structures and lack of standardized analytical methods hinder reliable characterization.

Purpose of the Study:

• To evaluate established and novel methods for characterizing lipid-based nanoparticles.
• To assess these methods across diverse liposomal and LNP formulations.
• To inform the development of standardized characterization protocols.

Main Methods:

• Cryogenic transmission electron microscopy (cryo-TEM) for morphology and lamellarity.
• Particle sizing techniques (e.g., dynamic light scattering).
• Small-angle X-ray scattering (SAXS) for structural details in liquid.
• RNA-specific assays for quantification.
• Advanced electron and mass spectrometry for surface chemistry and single-particle analysis.

Main Results:

• Cryo-TEM distinguished liposome structures and confirmed LNP consistency.
• Dimensional methods provided complementary size data but revealed method-dependent artifacts.
• SAXS offered insights into bilayer thickness and multilamellar spacing.
• RNA assays accurately quantified encapsulated RNA.
• Advanced techniques provided molecular-level surface and single-particle insights.

Conclusions:

• No single method is sufficient for comprehensive characterization of lipid-based systems.
• A metrologically informed, multimodal approach is critical.
• This approach supports reproducible data generation and the development of nanomedicine standards.