Raman spectra are collected using a 785 nm excitation (~280 mW) from 150 to 1925 cm -1 at a 4 cm -1 resolution. The Zetasizer Nano system incorporates proprietary non-invasive backscatter (NIBS) detector technology with electrophoretic (ELS) static (SLS) and dynamic (DLS) light scattering to determine proteins’ hydrodynamic radius from 0.15 nm to 5 µm, from 0.1 mg/mL to > 100 mg/mL. The Zetasizer Helix (ZS Helix) from Malvern Panalytical incorporates a fiber-coupled Raman spectrometer with a Zetasizer Nano ZSP to provide Raman (conformational stability) and DLS (colloidal stability) in sequence on a single sample. This article describes how DLS can be used to understand the colloidal stability of protein therapeutics. The results obtained from Raman spectroscopy and DLS on the same sample may give unique insights into the mechanisms of unfolding and aggregation. Secondary and tertiary structure of protein, onset temperature of aggregation, melting temperature, transition enthalpy values, protein solubility, aggregation propensity, and the potential for high viscosities at formulated concentrations can all be derived. Raman spectroscopy is another well-established technique that derives information about the secondary and tertiary structure of protein by monitoring molecular vibrations.īy integrating these two analytical techniques into a single instrument, a range of physical, chemical and structural parameters can be determined. The NanoBrook 90Plus in association with an autotitrator could be a suitable system for monitoring protein samples for aggregation.Sponsored by Malvern Panalytical Sep 5 2014ĭynamic light scattering (DLS) is a well-known technique used for determining sample interactions, sample polydispersity and the hydrodynamic diameter of biotherapeutic proteins in solution. Protein aggregation in samples can occur due to changes in pH or temperature. Based on the principles of Dynamic Light Scattering (DLS), most measurements only take a minute or two. The NanoBrook 90Plus particle size analyzer is designed for fast, routine, sub-micron measurements. The presence of aggregates is known to negatively affect SAXS and SANS results, consequently, scientists can use DLS as a selection tool to make sure protein samples are “good” candidates for their measurements". He added "SAXS or SANS are powerful techniques used to extract structural parameters and determine the overall structures and shapes of biological macromolecules, complexes and assemblies in solution. Protein scientists particularly like DLS because it provides them with a simple, fast and non-destructive test for aggregate detection, where the very same sample can also be used for Small-Angle X-ray Scattering (SAXS) or Small-Angle Neutron Scattering (SANS) experiments". Testa Analytical Solutions reports on interest from protein scientists to use Dynamic Light Scattering (DLS) as a tool for screening for the presence of aggregates, as it is extremely sensitive to these larger compounds.Īpplications Lab Manager Raffaele Carano said "Protein aggregation is a common challenge in the manufacturing of biological products.