Characterizing Vaccines with the Light Scattering Toolkit

Importance of the Topic

Vaccines are critical for disease prevention in humans and animals. Modern subunit, conjugate and nanoparticle vaccines span wide physicochemical ranges. Light scattering techniques measure fundamental attributes—size, molar mass, hydrodynamic radius, zeta potential and concentration—which are vital for design, production and quality control of vaccine formulations and adjuvants.

Objectives and Overview

This article reviews the light scattering toolkit in vaccine R&D and manufacturing. It explains the principles and instrumentation of static, dynamic and electrophoretic light scattering, as well as fractionation approaches. Case studies illustrate applications to subunit vaccines, polysaccharide conjugates, viruses, virus-like particles, lipid nanoparticles, adjuvants and process monitoring.

Methodology

• Multi-Angle Light Scattering (MALS) determines absolute molar mass and radius from Rayleigh scattering vs angle.
• Dynamic Light Scattering (DLS) measures hydrodynamic radius via intensity fluctuations and autocorrelation analysis.
• Electrophoretic Light Scattering (ELS) assesses electrophoretic mobility and calculates zeta potential by Doppler shift.
• Size-Exclusion Chromatography (SEC-MALS) and Field-Flow Fractionation (FFF-MALS) provide high-resolution separations coupled to light scattering detectors.
• Composition-Gradient MALS (CG-MALS) characterizes solution-phase binding stoichiometry and affinity without labels.
• Real-Time MALS (RT-MALS) with process-oriented detectors monitors molar mass, size and concentration in-line during production.

Použitá instrumentace

• DAWN, microDAWN, miniDAWN (MALS detectors)
• Optilab differential refractometer (RI detector)
• DynaPro Plate Reader, DynaPro NanoStar, Mobius (batch DLS and ELS)
• WyattQELS module (inline DLS)
• Calypso composition-gradient delivery system (CG-MALS)
• Eclipse FFF system (field-flow fractionation)
• ultraDAWN with OBSERVER software (RT-MALS)

Main Results and Discussion

• Subunit vaccines: SEC-MALS and CG-MALS revealed oligomeric state and antibody binding stoichiometry. Conjugate analysis quantified glycan loading on viral glycoproteins.
• Polysaccharide conjugates: SEC-MALS and FFF-MALS determined size distributions and monitored degradation and immunogenicity dependence on polysaccharide chain length.
• Viruses and VLPs: FFF-MALS quantified total particle count, size distribution and aggregates. Conjugate analysis measured nucleic acid payload in VLPs and lipid nanoparticles.
• Lipid nanoparticles: FFF-MALS and Mobius DLS/ELS assessed size uniformity, zeta potential and trace aggregation, guiding formulation optimization.
• Adjuvants: Mobius measured zeta potential and size of aluminum oxyhydroxide. DLS validated temperature-responsive micellar assemblies for self-adjuvanting polymers.
• Process monitoring: RT-MALS enabled in-line control of viral purification by triggering fraction collection based on real-time size and concentration data.

Benefits and Practical Applications

Light scattering techniques provide label-free, absolute measurements of key vaccine attributes. Their integration with chromatographic and fractionation methods enables detailed quality assessment, streamlined formulation screening and robust process control. These approaches reduce development time, ensure batch-to-batch consistency and support regulatory compliance.

Future Trends and Possibilities for Use

• Enhanced integration of PAT tools for fully automated, feedback-controlled vaccine manufacture.
• Higher throughput fractionation and microfluidic platforms for rapid screening of formulations.
• Advanced binding analysis combining CG-MALS with kinetics modules for multivalent interactions.
• Expansion of light scattering to novel nanocarriers, biomaterial scaffolds and lipid-protein hybrid systems.

Conclusion

The light scattering toolkit—including MALS, DLS, ELS, SEC-MALS, FFF-MALS, CG-MALS and RT-MALS—offers comprehensive, quantitative insights into vaccine and adjuvant structure and composition. Its application accelerates discovery, optimizes formulations, enhances process control and underpins quality assurance in vaccine development and manufacturing.

Reference

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