January 27, 2022
02:00 PM
Louvain-La-Neuve
Auditorium SUD03
Encapsulation of Commensal Skin Bacteria in Soft Patches Based on Layer-by-Layer Assembly by Wanlin XU
The commensal skin bacterium Staphylococcus epidermidis provides a range of benefits to human hosts, contributing to skin equilibrium and good health. However, it can also act as a pathogen when entering the host body. Encapsulation is thus considered as a way to maintain the benefits of bacteria and control bacteria dispersion. Among various materials, porous polycarbonate membranes modified by layer-by-layer (LbL) assembled multilayers attract an increasing interest. In this thesis, two membrane-based methods have been studied to entrap bacteria.
In the first method, a microtube mat is fabricated to encapsulate S. epidermidis. A bicompartmentalized LbL microtube, which contains an erasable external compartment, is designed to release the inner tube without having to dissolve the membrane template in non-biocompatible organic solvents. A hydrogen-bonded poly(N-vinyl caprolactam) PVCL/ poly(methacrylic acid) (PMAA) system is chosen to build this erasable compartment. The use of PVCL/PMAA multilayers as a sacrificial compartment is proved to provide an efficient release of nano/micro-structures in biocompatible aqueous conditions. S. epidermidis can be entrapped in LbL microtube under optimized loading conditions and the resulting microtube mat is shown to maintain the viability of S. epidermidis. However, the bacterial metabolic activity remains limited.
Therefore, a second method of entrapping S. epidermidis in a membrane-in-gel patch is studied. S. epidermidis is loaded in LbL modified membrane, followed by coating the membrane with a thick layer of agarose gel. The membrane-in-gel maintains the metabolic activity of bacteria. LbL multilayers comprising antibacterial polycations are then deposited over the patch. By varying the multilayer composition, thickness, and nature of the last layer, both the probability of escape and the metabolic activity of entrapped bacteria can be tuned. This encapsulation methodology thus offers strong interest for the development of a range of applications in which bacteria need to be controlled, beyond the specific case of commensal skin bacteria encapsulation.
Jury members :
- Prof. Alain M. Jonas (UCLouvain), supervisor
- Prof. Karine Glinel (UCLouvain), supervisor
- Prof. Sophie Demoustier-Champagne (UCLouvain), chairperson
- Prof. Christine Dupont (UCLouvain), secretary
- Prof. André Skirtach (U. Ghent)
- Dr. Lydie Ploux (U. Strasbourg, France)
Pay attention :
The public defense of Wanlin Xu scheduled for Thursday 27 January at 2:00 p.m will take place in the form of a video conference