Modeling the Gibbs–Donnan effect during ultrafiltration and diafiltration processes using the Poisson–Boltzmann theory in combination with a basic Stern model

Briskot, Till; Hillebrandt, Nils; Kluters, Simon; Wang, Gang; Studts, Joey; Hahn, Tobias; Huuk, Thiemo; Hubbuch, Jürgen

doi:10.1016/j.memsci.2022.120333

Cited by 18 publications

(6 citation statements)

References 38 publications

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“…In biotechnological applications, solutions with a high concentration of protein are often used. For instance, excipient solutions with a protein concentration exceeding 100 g/L are often used during ultrafiltration/diafiltration processes in biopharmaceutical manufacturing [ 233 , 234 , 235 , 236 ]. The term “macromolecular crowding” (MCr) has been coined to describe such conditions of high concentration of macromolecules and nanoparticles [ 237 , 238 , 239 , 240 ].…”

Section: Weak Polyelectrolytes In Crowded Systemsmentioning

confidence: 99%

Unusual Aspects of Charge Regulation in Flexible Weak Polyelectrolytes

et al. 2023

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This article reviews the state of the art of the studies on charge regulation (CR) effects in flexible weak polyelectrolytes (FWPE). The characteristic of FWPE is the strong coupling of ionization and conformational degrees of freedom. After introducing the necessary fundamental concepts, some unconventional aspects of the the physical chemistry of FWPE are discussed. These aspects are: (i) the extension of statistical mechanics techniques to include ionization equilibria and, in particular, the use of the recently proposed Site Binding-Rotational Isomeric State (SBRIS) model, which allows the calculation of ionization and conformational properties on the same foot; (ii) the recent progresses in the inclusion of proton equilibria in computer simulations; (iii) the possibility of mechanically induced CR in the stretching of FWPE; (iv) the non-trivial adsorption of FWPE on ionized surfaces with the same charge sign as the PE (the so-called “wrong side” of the isoelectric point); (v) the influence of macromolecular crowding on CR.

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Section: Weak Polyelectrolytes In Crowded Systemsmentioning

confidence: 99%

Unusual Aspects of Charge Regulation in Flexible Weak Polyelectrolytes

et al. 2023

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“…This difference in pH is also evidenced by experimental measurements in membrane-based separation processes. 7 Nevertheless, Levin and Bakhshandeh stated in their recent publication 8 that “electrochemical potential of an ion inside the system and in the reservoir is the same. Recall that inside the simulation cell, the electrochemical potential of an ion includes the Donnan potential.…”

Section: The Donnan Potentialmentioning

confidence: 99%

“…Therefore, without loss of generality, we discuss only this case, noting that analogous arguments and formulas can be derived for the ACP procedure. 4 The correction proposed by Labbez and Jo ¨nsson 4 was presented as eqn (7) in the comment, albeit using a different notation. Labbez and Jo ¨nsson noted that their correction ''amounts to simply correct the trial energy of titration, eqn (3), by the excess chemical potential of the 'unwanted' ion''.…”

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confidence: 99%

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Reply to the ‘Comment on “Simulations of ionization equilibria in weak polyelectrolyte solutions and gels”’ by J. Landsgesell, L. Nová, O. Rud, F. Uhlík, D. Sean, P. Hebbeker, C. Holm and P. Košovan, Soft Matter, 2019, 15, 1155–1185

et al. 2023

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“…The main objective of UFDF is to increase the product concentration through volume reduction (UF) and buffer exchange to final formulation buffer (DF) [ 10 ]. Targeting high protein concentration at the UFDF step possess a series of challenges, such as volume exclusion and Donnan equilibrium effects [ 11 , 12 ]. Final protein and excipient concentrations are based on either weight or theoretical calculations of the concentration factor.…”

Section: Introductionmentioning

confidence: 99%

In‐line monitoring of protein concentration with MIR spectroscopy during UFDF

Milewska¹,

Baekelandt²,

Boutaieb³

et al. 2022

Engineering in Life Sciences

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Rapid increase of product titers in upstream processes has presented challenges for downstream processing, where purification costs increase linearly with the increase of the product yield. Hence, innovative solutions are becoming increasingly popular. Process Analytical Technology (PAT) tools, such as spectroscopic techniques, are on the rise due to their capacity to provide real-time, precise analytics. This ensures consistent product quality and increased process understanding, as well as process control. Mid-infrared spectroscopy (MIR) has emerged as a highly promising technique within recent years, owing to its ability to monitor several critical process parameters at the same time and unchallenging spectral analysis and data interpretation. For in-line monitoring, Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR) is a method of choice, as it enables reliable measurements in a liquid environment, even though water absorption bands are present in the region of interest. Here, we present MIR spectroscopy as a monitoring tool of critical process parameters in ultrafiltration/diafiltration (UFDF). MIR spectrometer was integrated in the UFDF process in an in-line fashion through a single-use flow cell containing a single bounce silicon ATR crystal. The results indicate that the one-point calibration algorithm applied to the MIR spectra, predicts highly accurate protein concentrations, as compared with validated offline analytical methods.

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Modeling the Gibbs–Donnan effect during ultrafiltration and diafiltration processes using the Poisson–Boltzmann theory in combination with a basic Stern model

Cited by 18 publications

References 38 publications

Unusual Aspects of Charge Regulation in Flexible Weak Polyelectrolytes

Unusual Aspects of Charge Regulation in Flexible Weak Polyelectrolytes

Reply to the ‘Comment on “Simulations of ionization equilibria in weak polyelectrolyte solutions and gels”’ by J. Landsgesell, L. Nová, O. Rud, F. Uhlík, D. Sean, P. Hebbeker, C. Holm and P. Košovan, Soft Matter, 2019, 15, 1155–1185

In‐line monitoring of protein concentration with MIR spectroscopy during UFDF

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