Squeeze flow rheometry as a novel tool for the characterization of highly concentrated protein solutions. Issue 3 (26th October 2015)

• Record Type: Journal Article
• Authors: Schermeyer, Marie‐Therese; Sigloch, Heike; Bauer, Katharina C.; Oelschlaeger, Claude; Hubbuch, Jürgen
• Is Part Of: Biotechnology and bioengineering. Volume 113:Issue 3(2016)
• Page Start: 576
• Page End: 587
• Publication Date: 2015-10-26
• Subjects: protein phase behavior -- solubility -- formulation -- rheology -- storage and loss modulus; Biotechnology -- Periodicals; Bioengineering -- Periodicals; 660.6
• DOI: 10.1002/bit.25834
• Languages: English
• ISSNs: 0006-3592

Abstract

ABSTRACT: This study aims at defining rheological parameters for the characterization of highly concentrated protein solutions. As a basis for comparing rheological behavior with protein solution characteristics the protein phase behavior of Lysozyme from chicken egg white with concentrations up to 225 mg/mL, changing pH values and additive concentrations was studied in a microbatch scale format. The prepared phase diagrams, scored after 40 days ( t 40 ) give insights into the kind and kinetics of the phase transitions that occur. Oscillatory frequency sweep measurements of samples with exactly the same conditions were conducted immediately after preparation ( t 0 ). The protein solutions behave viscoelastic and show a characteristic curve shape of the storage modulus (G′) and the loss modulus (G″). The graphs provide information about the cross‐linking degree of the respective sample. The measured rheological parameters were sensitive concerning solution composition, protein concentration and solution inner structure. The rheological moduli G ′ and G ″ and especially the ratio of these parameters over a frequency range from 100 to 40000 rad/sec give information about the aggregation tendency of the protein under tested conditions. We succeeded to correlate protein phase behavior with the defined rheological key parameter ω C O . This point represents the frequency value of the intersection point from G′ and G″. In our study Lysozyme expressed a ω C O threshold value of 20000 rad/sec as a lower limit for stable protein solutions. The predictability of lysozyme aggregation tendency and crystallization by means of squeeze flow rheometry is shown. Biotechnol. Bioeng. 2016;113: 576–587. © 2015 Wiley Periodicals, Inc. Abstract : This article presents a novel analytical technique to characterize highly concentrated protein solutions with regard to their phase behavior. With Squeeze flow rheological measurements and the definition of ωCO the authors could predict the phase behavior of Lysozyme in various solution conditions. This analytical method can be performed immediately after sample preparation and independent on solution condition and is thus a clear step towards a better understanding of protein solution characteristics.