Copy of Development of interfacial models to understand preservation through neutron reflection

Cosmetic preservation is vital to ensure required shelf life, avoid costly product recalls and control bio-contaminations that may lead to consumer infections. However, little is known about the mechanistic processes leading to preservative biocidal action. This project aims to begin filling the gap, thereby providing insights key to preservation development. The key aim of this study is to explore how surface activities of additive molecules function in boosting the biocidal efficacy of preservatives against a broad spectrum of microbes, primarily focusing on propylene glycol monocaprylate (PGMC) with preservative, phenoxyethanol (PE), as this pair is currently most attractive combined preservative. Inner Gram-negative membrane models using POPC/POPG (7:3) phospholipid monolayers have been developed (inspired by the work of Ciumac D et al. JCIS 2021). Pressure area isotherms have been performed using the Langmuir trough, to expose the structural changes on this membrane mimic due to active adsorption. A Neutron Reflection study has been conducted in 3 days of beamtime on INTER at ISIS on the monolayer in the 4 systems at 3 trough areas: 150 cm2, 125 cm2 and 100 cm2, to reveal the structural changes behind this behaviour. Final contrasts are required in a further 3 days of beamtime ahead of upcoming publication.