Structure and dynamics of biopolymer-based systems investigated by neutron scattering

Research Project, 2018 – 2020

The project aims for studying the structure and dynamics of biopolymer-based systems investigated by small angle neutron scattering (SANS). The biopolymer-based systems related to this study is a nanostructure of aqueous mixtures of polygalacturonic acid (PGA) and beta-lactoglobulin (BLG) in presence of calcium ions at neutral pH. Mixtures of anionic polysaccharides and globular proteins are of great interest with respect to the design of innovative biomaterials and to their large variety of applications in the food, pharmaceutical, biotechnology and cosmetic industries. The PGA/BLG hydrogel system that will be studied has potential to be used in controlled release system within the food or pharmaceutical area. The key point of our study stems from the fact that we focus on the case where the PGA/BLG system is studied in the presence of Ca2+. In such system, the Ca2+ will act to induce a crosslinked PGA network and tuning electrostatic interactions.

The aim of the research is to examine if there is a relationship between the structure and the function of the gels, for example the texture and the ability for the gel to entrap and release drugs. This will be done by combining ‘classical’ characterization techniques together with imagine through neutron scattering. Earlier studies where using SANS on BLG/low methoxy pectin coacervates have shown that the self-aggregation of BLG promotes the formation of protein domains.

Using this hydrogel (Ca-BLG-PGA) to entrap molecules (drug) is original since many gels are obtained by heat treatment which could degrade the drug. Using the BLG in the mixture could also be very positive because of its ability to bind small molecules. We expect to finely tune the structure by playing on several parameters such as the ratio (PGA/BLG), the physical state of the protein, the amount of calcium and, chemical modification of the polysaccharide. The management and the control of the structure are the best way to control the drug release

The outcome of the study includes training and experimental practice of neutron scattering instrument followed by knowledge transfer for increasing the interest of using neutron scattering, especially in the field of biopolymers and different types of polysaccharides.