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. 2018 Jul 17;10(3):94.
doi: 10.3390/pharmaceutics10030094.

Dynamic Light Scattering of Biopharmaceutics-Can Analytical Performance Be Enhanced by Laser Power?

Simone Aleandri  1 , Andrea Vaccaro  2 , Ricardo Armenta  3 , Andreas Charles Völker  4 , Martin Kuentz  5
Affiliations

Dynamic Light Scattering of Biopharmaceutics-Can Analytical Performance Be Enhanced by Laser Power?

Simone Aleandri et al. Pharmaceutics. .

Abstract

Background: Dynamic light scattering (DLS) is an important tool to characterize colloidal systems and adequate sizing is particularly critical in the field of protein formulations. Among the different factors that can influence the measurement result, the effect of laser power has so far not been studied thoroughly.

Methods: The sensitivity of a DLS instrument was first considered on a theoretical level, followed by experiments using DLS instruments, equipped with two different lasers of (nominal) 45 mW, and 100 mW, respectively. This work analyzes dilute colloidal dispersions of lysozyme as model protein.

Results: Theoretical findings agreed with experiments in that only enhanced laser power of 100 mW laser allowed measuring a 0.1 mg/mL protein dispersion in a reliable manner. Results confirmed the usefulness of the presented theoretical considerations in improving a general understanding of the limiting factors in DLS.

Conclusions: Laser power is a critical aspect regarding adequate colloidal analysis by DLS. Practical guidance is provided to help scientists specifically with measuring dilute samples to choose both an optimal instrument configuration as well as a robust experimental procedure.

Keywords: dynamic light scattering (DSL); laser power; lysozyme; protein aggregation; protein formulation.

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Conflict of interest statement

A.V., R.A., and A.C.V. were at the time of the study employees of LS Instruments (Switzerland).

Figures

Figure 1
Figure 1
Depiction of the dynamic light scattering (DLS) apparatus with two different lasers of nominal powers 45 mW, and 100 mW, respectively. The sample is only schematically depicted to visualize the measurement principle.
Figure 2
Figure 2
Minimum measurable particle concentration as a function of the maximum available laser power for the case of lysozyme and instrument sensitivity as detailed in Section 4.3. The vertical dashed line marks the boundary between the two regimes as detailed in the text.
Figure 3
Figure 3
Hydrodynamic radius (Rh) (A) and scaled count rate (B) of lysozyme at different concentration (100 mW laser intensity).
Figure 4
Figure 4
Intercept of lysozyme at different concentrations (A) and correlation function of lysozyme at lowest detectable concentration (B) (0.1 mg/mL, 100 mW laser intensity).
See this image and copyright information in PMC

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