Internal membrane fouling by proteins during microfiltration

Comparative Evaluation of the Performance of Sterile Filters for Bioburden Protection and Final Fill in Biopharmaceutical Processes

“…Adding excipients could reduce potential protein aggregation [ 29 ] and prevent undesired flux decline. Lay et al [ 30 ] found that electrically charged MF membranes could mitigate the fouling effect of counter-ion charged substances. For stable sterile filtration, further investigations are needed to understand the flux decline mechanism of high concentration products and the effective prevention methods.…”

Unraveling pH Effects on Ultrafiltration Membrane Fouling by Extracellular Polymeric Substances: Adsorption and Conformation Analyzed with Localized Surface Plasmon Resonance

“…However, because of the viscoelastic properties of the layer adsorbed to the QCM-D sensor, frequency shift is usually misleading as a sole indicator of the mass adhered to the surface, and changes in dissipation energy of the sensor are required to accurately monitor the mass adhered to the surface. As such, QCM-D, which monitors changes in dissipation and in resonance frequency, provides insight into the viscoelastic and inertial characteristics of the deposited layers. − Hence, QCM-D is commonly used to track the hydration of fouling layers ex situ − as well as the entire mechanical load of a tested fouling layer on top of membrane-mimetic sensor’s surface. , This type of analysis will not always correlate with the effect of a similar adsorbed layer on a membrane, because resolving properties such as shape and conformation of adsorbed biomacromolecules with QCM-D can be problematic, because there is a significant contribution of water trapped within the interior of the adsorbent (internal hydration) as well as water coupled externally to the adsorbate (external hydration) on the entire mechanical load of the adsorbed foulants on the sensor. This causes a mismatch between the length scales of the adsorbed biomacromolecules (∼few nm) and the QCM-D measurement that provides the entire mechanical load on the piezoelectric sensor in a length scale of up to 300 nm. , Therefore, in this study, a localized surface plasmon resonance (LSPR) sensing has been applied to explore EPS interfacial properties (adsorbate surface concentration up to 30 nm from the surface), in parallel to acquiring viscoelastic properties of the adsorbed EPS layer by QCM-D.…”

Considerations of the limitations of commonly applied characterisation methods in understanding protein-driven irreversible fouling

“…Furthermore, an understanding of the collective impacts of electrostatic and non-electrostatic forces with morphology on UF membrane performance is still required. 26,36–38…”