Design of “cell-in-shell” hybrid materials (hybrid cells)

: synthesis, structuration, functionalization and application

Abstract

Cells, the most basic units in living systems, are responsible for conducting the essential processes of life. The properties of cells are reflected in the selectivity, activity and self-regulation and reprogramability in the biological processes, which can be envisaged as sources of inspiration to find solutions to important problems faced in modern technology. However, the natural nanostructures and functions of cells limit their widely applications. The ability to create large numbers of non-natural nanostructures and functions on cells to widen the cells applications should have great technologic and scientific significance.

This thesis focuses on the design of “cell-in-shell” hybrid materials (hybrid cells), in which cells are hybridized with structured or functional coating materials in order to enhance the natural functions of cells or enable them to perform new functions that do not exist in their original specialization.

Three examples of hybrid cells design based on typical prokaryotes or eukaryotes are demonstrated in this thesis, which refers to the investigation and discussion on the synthesis, nanostructure, function and application. Firstly, yolk-shell photosynthetic hybrid cells with hierarchically-ordered porous shells were designed on cyanobacteria through protamine-assisted colloidal packing of uniform silica nanoparticles, which provide an example on the hybrid cells formation mechanism exploration and high-performance nanostructures construction. Secondly, functional hybrid cells which were synthesized through single-cell encapsulation on yeast cells with polydopamine (PDA) - based shells exhibit not only a significant enhancement of the original cellular functions but also an extension of the non-original functions on living cells, thus giving a pioneering inspiration on the multi-functionalization of hybrid cells. Thirdly, biocatalytic hybrid cells were designed through the introduction of PDA shells and ordered porous silica shells on the yeast cells encapsulated within alginate hydrogel beads, in order to improve the activity, stability and mass permeability of hybrid cells in the biocatalysis, thus solving some critical problems in biocatalytic industry and pushing hybrid cells one step closer to the practical applications.

In summary, the works presented in this thesis demonstrate the synthesis approaches, nanostructure construction, function enhancement and application extension of the hybrid cells, in order to highlight the significance of hybrid cells in future researches and industry.

Date of Award	11 Oct 2017
Original language	English
Awarding Institution	University of Namur
Supervisor	BAO LIAN SU (Supervisor), Pierre Van Cutsem (President), Stephane Vincent (Jury), Johan Wouters (Jury), Fabrice Franck (Jury) & Xiaoyu Yang (Jury)