High-Throughput Light Scattering Tools for Characterizing and Formulating Macromolecules and Nanoparticles

Daniel Some, Wyatt Technology Corp., Santa Barbara, United States

Light scattering technology offers a suite of experimental techniques for determining, from first principles, the basic physical properties of macromolecules and nanoparticles in solution/suspension, including molecular weight, size, charge, interactions, conformation and conjugation.

One of the most commonly used light scattering tools is SEC-MALS - the coupling of size exclusion chromatography or gel permeation chromatography to multi-angle light scattering. SEC-MALS directly determines the molecular weight and size of proteins and polymers without recourse to column calibration or elution time. It is an absolute technique in that it requires no molecular standards, and therefore is suitable for characterizing a variety of entities for which such standards do not exist. The upstream separation by SEC means that relatively high-resolution distributions of molar mass and size may be obtained.

Another well-known light scattering tool is DLS - dynamic light scattering. DLS directly determines the diffusion coefficients of macromolecules, colloids and nanoparticles. Size and low-resolution size distributions are derived even without separation, often as a function of time or temperature.

These and other light scattering tools are widely applied in the fields of life sciences, synthetic and natural polymer research, colloid science and nanotechnology because they offer unique insights into key properties and behavior with relative simplicity and high sampling efficiency.

In this talk I will briefly describe the differences between MALS and DLS, then introduce two high-throughput tools based on light scattering:

• µSEC-MALS - a new low-volume MALS detector coupled to UHPLC-SEC, which can perform traditional SEC-MALS analyses, including characterization of conjugated proteins, copolymers and branched polymers, under the rapid separation regime afforded by UHPLC
• HT-DLS - high-throughput, automated dynamic light scattering performed in situ in standard microwell plates with no fluid handling beyond pipetting into the plates.
  

Examples of the applications of these tools will focus on formulation and process/method development for therapeutic proteins and nanoparticles.