Characterization of the hydrophilization treatment on nonwoven membranes for cell culture

Details

Supervisors

Dupont-Gillain, Christine C.

Faculty

Faculté des bioingénieurs

Degree label

Master [120] : bioingénieur en chimie et bioindustries, à finalité spécialisée

Abstract

Univercells technologies (UTEC) recently developed bioreactors including the Scale-XTM. This bioreactor is used for mammalian cell culture often aiming at virus production. Since mammalian cells need to adhere to a surface to proliferate, different techniques exist to develop surfaces featuring the required properties for cell growth. The Scale-XTM is a single-use fixed-bed bioreactor consisting of three layers: one layer of netting in polypropylene and two layers of nonwoven polyethylene terephthalate (PET) providing the cell growth surface. The nonwoven PET membrane is advantageous to obtain a high cell density but impedes cell adhesion due to its hydrophobicity. Therefore, PET is hydrophilized to support cell growth. The aim of this master thesis is to identify and develop a valid quality control (QC) method. Therefore, some requirements are stated comprising low cost, short time for testing per fixed bed, a representative sample size, a non-destructive method, and a quantitative result. Overall, a correlation must be established between the QC test result and the wetting properties of the membranes, which in turn are linked to cell adhesion performances. Before performing QC tests, the morphology of the membrane was characterized by microcomputed tomography (µCT) and optical microscopy (OM). These techniques permitted an estimation of the fibers width around 30 µm. The porosity of the membrane was also approximated at 85% by µCT along with calculations based on the specific mass. Thereafter, three potential QC tests were carried out: infrared spectroscopy (in two different modes), contact angle measurements, and the vertical wicking test. After performing two different methods in IR spectroscopy, neither gave promising results to become a potential QC method. Another simpler method is the contact angle measurement. Through this method, a clear distinction could be made between treated and untreated samples since the drop was instantly absorbed in treated samples whereas the drop remained in place on untreated samples. However, the method failed to give precise data. Therefore, a vertical wicking test was performed, in which water coloured by a dye was used to evaluate capillarity in the membranes, giving very nuanced results between the treated samples. The vertical wicking test as well as the contact angle measurements are promising QC methods, but more research is still necessary for a better understanding of the results.