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FP7

MICSED Résumé de rapport

Project ID: 606869
Financé au titre de: FP7-PEOPLE
Pays: United Kingdom

Periodic Report Summary 1 - MICSED (MICSED - Molecular Interactions in Complex Systems)

The MICSED (Molecular Interactions in Complex Systems European Doctorate) is supporting five Early Stage Researchers (ESRs). They are working on a range of exciting projects delivering molecular-level insight into the complex physics and chemistries that lie behind modern consumer goods. Success in the projects will deliver new scientific knowledge but also allow step-changes in the efficacy of products used by billions of consumers world-wide. It will also allow increased product stability leading to significant sustainability gains in manufacturing, formulation, packaging and transport costs. The ESRs spent the first twelve months of their research programmes at Durham University based in either the Chemistry or Maths Departments, then moved to secondments at P&G innovation centres in Belgium and Germany. They’ll later return to Durham to complete their PhDs.
The principal scientific objectives of the MICSED programme are to:
1. Establish a theory to predict the length and timescale of small molecule migration in complex soft matter environments and on target surfaces and the impact of this process on mechanical properties.
2. Develop analytical methods and provide experimental data on small molecule partitioning in complex environments and the impact on adhesive strength to allow predictive models for future products.
3. Develop tools to access physico-chemical parameters that trigger diffusion, partitioning, evaporation and migration of actives in consumer goods formulations and of small and mid-size molecular weight components in hygiene adhesives during storage and application on target surfaces.
4. Provide detailed mechanistic insight into protein degradation pathways in complex fluids.
5. Develop a toolkit of methods to provide mechanistic understanding of reactive oxygen species in complex environments.
The molecular-scale challenges that the MICSED programme aims to address has been organised into 4 separate areas which form the four research work-packages (WPs) that Early Stage Researchers (ESRs) are contributing to.
ESRs 1 & 2 (Salvatore Croce and Elise Sabbatie) have been working on the important problem of small molecule migration through polymer matrices from a theoretical and experimental viewpoint respectively. Molecular migration is crucial in areas such as determining the stability and performance of adhesives and the migration of active ingredients through polymer membranes in unit-dose applications. The ability to understand and control migration leading to more predictable performance will reduce over-engineering of many products, allow better predictions of product stability, potentially extending product lifetimes. Salvatore’s project has focussed on the development of new theoretical approaches to understanding migration. In particular he has investigated the impact of matrix elasticity on the surface segregation of migrants in a polymer matrix. He has extended both Schmidt-Binder and Self Consistent Field Theories to include elastic terms, and finds that increasing Bulk Modulus (for example via polymer cross-linking) causes significant reduction in surface segregation and can prevent the formation of wetting layers. This offers a potential method for controlling segregation. A paper outlining the theoretical developments has been submitted for publication (arXiv:1509.07311). Working with scientists at the P&G German innovation centre at Schwalbach, Salvatore is extending his theory to more complex systems and validating it against experimental data.
Elise has been performing a range of experiments to measure segregation in a number of model systems where the chemical compatibility of migrant and matrix is systematically changed. Using a combination of ion beam analysis and neutron reflectometry on selectively-deuterated samples she has measured systems which change systematically from a homogenous distribution to weak segregation (where migrant concentration falls off exponentially with depth) to formation of a wetting layer which is thick on the molecular lengthscale. Elise’s experimental data provide a stringent test of Salvatore’s theoretical developments; we find that his models provide excellent two-parameter explanations of the data allowing estimation of surface energy and surface composition. Elise is now working at P&G in Germany on low-field NMR-based methods to determine the depth profile of oligomers over length scales up to 2 mm – completing the link between microscopic phenomenology on model systems and real-world products. She’ll also be probing Salvatore’s predictions on elasticity-control of migration experimentally. Her first paper on the experimental methods she’s developed is in preparation.
ESR4 (Niamh Ainsworth) is working on the area of enzyme stability, with a particular emphasis on laundry applications. Enzymes such as proteases, amylases and lipase are crucial components of modern detergents that enable the global adoption of lower temperature washes with huge benefits in terms of energy reduction. One of the key issues, particularly with liquid or “unit dose” formulations and in warm-climate markets, is enzyme stability. Niamh has been investigating a range of methods for measuring stability in product formulations where many conventional assays are rendered impractical. Particularly promising methods include nano-differential-scanning calorimetry and a new pulsed proteolysis method, both of which probe Tm, the characteristic temperature for protein unfolding. Pulse proteolysis works by using a protease, thermolysin, that is selective for the hydrophobic portions of the enzyme that are protected in the folded state. Unfolded enzymes are broken down such that detection of a mass component corresponding to the intact enzyme (for example by gel or HPLC methods) signals enzyme stability. Quantification of the temperature dependence of the relative amounts of folded and unfolded protein allows access to a Tm value, which can be achieved in detergent formulation environments of different complexities. The results she obtains will be bench-marked against conventional storage-based methods at P&G Brussels, which use activity-based spectrophotometric assays as measures of enzyme stability. Niamh’s new methods applied in detergent media will particularly target earlier detection of protein denaturation when activity assays still show close to maximal enzyme performance. Niamh will therefore be able to develop new screening technologies for the faster evaluation of the short and longer term stabilities of new biological cleaning technologies globally. She is preparing a tutorial review article on her toolbox of techniques for Chem. Soc. Rev. to disseminate the methods she has developed.
ESR5 (Anna Stanczak) is developing molecular probes which will help understand the fundamental role played by “reactive oxygen species” (ROS) such as the hydroxyl radical, peroxides and singlet oxygen in the wash cycle. One of the major challenges is to identify probes that are stable in the alkaline conditions of a typical wash, that give a response to the presence of a specific ROS in the presence of others and that provide a unique spectroscopic signal without interference from other species present such as optical brighteners. She has identified effective methods to generate each ROS under model laundry conditions, which have allowed careful investigation and screening of the chemical and photophysical behaviours of a range of candidate probe species. This has allowed her to identify an efficient and effective probe for hydroxyl radicals based on fluorescence detection and for peracids and hydrogen peroxide based on time-resolved fluorescence. She is currently working on the final probes needed for singlet oxygen. In her placement at P&G Brussels Anna is starting to use these probes to follow the generation and fate of these ROS in mimics of laundry processes, allowing the real-time monitoring of bleaching agents through a wash-cycle for the first time.
ESR3 (Benjamin Devilliers) is working on the stability and delivery of hueing dye active species from complex formulations. Hueing plays a key role in delivering the brightness demanded by consumers, but there are enormous challenges in producing dyes that have appropriate properties in the formulation, have high stability, and have the correct deposition characteristics to give a rapid benefit without deleterious effects caused by over-deposition. The challenge is increased by the need for efficacy across a range of product types destined for different parts of the globe. Ben has been investigating how the spectral properties of key commercial dyes are influenced by solvent and surfactant environments, the kinetics of update on different model fabrics, and the influence of fabric type on efficacy. A key problem is the overstaining of fabrics by hueing dyes in certain formulations so Ben is investigating whether specific surfactants can help prevent dye overdeposition or suppress the absorbance if over-deposition occurs. He’s now based at P&G Brussels and working closely with P&G’s global team on this area.

Website
The project websites are at https://www.dur.ac.uk/micsed/ and https://micsed.wordpress.com/. They are maintained by the ESRs and project administrator.

Contact

Harle Wendy, (Director of Research Office)
Tél.: +441913344645
E-mail

Thèmes

Life Sciences
Numéro d'enregistrement: 183637 / Dernière mise à jour le: 2016-06-16
Source d'information: SESAM