To uncover how the polymers interact with mucin, Peter and Paola must look at their data in detail. As with all other stages of an experiment, their ISIS local contact can always be called upon to help with the analysis and interpretation.
So what did the SANS experiments reveal? The PEG polymer does not show any interaction with the mucin and diffuses through quite easily, while the smaller dendrimer, which has a positive charge depending on the pH, interacts electrostatically with the negatively-charge gel, so its movement is retarded. “The scattering indicates that the mucin structure collapses in the presence of the polymer,” says Paola.
Peter and Paola will now prepare their results for publication. Experiments performed at ISIS result in around 500 publications each year, as well as conference papers, posters and seminars. Users also have to send in a report giving experimental details and outcomes – the Facility Access Panels use these reports to assess previous experiments when users apply for further beam-time.
The Cardiff team has already put in a proposal for the next neutron experiment. “The results always give you a new idea,” says Peter. “We want to look at interactions with other uncharged polymers such as dextrin, and a negatively charged dendrimer, and also in the presence of agents that chemically break down mucin, such as N-acetylcysteine.”
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