Multiscale structuring and assembly of chitosan films for eco-friendly lab-on-a-chip applications

Context

In the current context of climate change, it is becoming urgent to propose new environmentally-friendly manufacturing processes based on bio-based materials. This issue is even more important for devices with a very short time life, such as lab-on-a-chip (LOC). LOCs are miniaturized devices with applications in various fields (chemistry, health, food and the environment). The global LOC market was estimated at 17 billion USD in 2023, and is expected to reach 55 billion UDS in 2032 [1]. In the case of medical applications, these devices are mainly intended for single use, for health reasons and/or test reliability. At present, LOCs are mainly manufactured from oil-based polymers, which entails environmental costs associated with both their manufacture and disposal. It is therefore necessary to develop sustainable green processes for the production of LOC [2].

Objective of the thesis

We have recently developed at INL, in collaboration with IMP (Institut des Matériaux Polymères), a process to obtain thick films of chitosan and demonstrated that it is possible to micro-structure them to make LOCs [3]. Chitosan, a polysaccharide derived from chitin and the second most abondant after cellulose on Earth, is produced from waste generated by the seafood industry (6 to 8 million tonnes per year [4]). Although we have succeeded in making the first LOCs from chitosan, there are still some technological hurdles to overcome. The aim of this thesis is therefore to pursue research into the manufacture of LOC made from chitosan, in order to propose a fully eco-responsible manufacturing process. The objectives of this thesis are :

o Optimize the chitosan film manufacturing process to obtain films that are insoluble in aqueous media or with a swelling rate of less than 10%.

o Study multi-scale (micro and nano) structuring of chitosan films by micro-drilling, nano-imprinting, hot-embossing and plasma etching.

o Design and manufacture LOC devices with different functions (separation, sorting, concentration, capture, detection).

o Evaluate fabricated LOCs with model systems such as beads for sorting or separation functions, or the streptavidin-biotin couple for capture and detection functions.

The INL's mission is to develop multidisciplinary technological research in the field of micro and nanotechnologies and their applications. The research carried out ranges from materials to systems, and is supported by Lyon's NanoLyon technology platform.

The candidate will have a Bac+5, Master's degree or equivalent (engineering diploma), and strong knowledge in Micro-Nanotechnologies, Physical chemistry of interfaces and/or Surface chemistry. Experience or a particular interest in microfluidics would be apreciated.In addition, he/she must demonstrate a strong interest for experimental research and teamwork. An open mind and special interest for interdisciplinarity and health applications are essential.