Delivering drugs by applying the active ingredient to the skin offers many potential benefits in pharmaceutical, dermatological, and cosmetic applications, and yet the interactions and transport mechanisms across the skin barrier are not yet thoroughly understood at the molecular level. Nanogels have attracted particular interest as possible carriers, because of their high surface-to-volume ratio, ability to form stable colloidal systems and the fact that their chemical structure can be tailored to achieve particular physicochemical properties, and to respond to stimuli.
In this study, a team of researchers used neutron reflectivity to study the interactions between thermo-responsive N-isopropylacrylamide (NPAM) based nanogels, cross-linked with 10%, 20% and 30% N,N'- methylenebisacrylamide (MBA), and skin lipid multi-bilayer models. They also investigated the effect of the penetration enhancer benzyl alcohol on these interactions.
The results show the importance of membrane free acids, enhancing the ability of nanogels to associate with skin lipids to form water-dispersible complexes. This association increased with the percentage of the MBA cross-linker and temperature. The researchers concluded that the nanogels mainly associate with skin lipid molecules through hydrophobic interactions.
The observed enhancement effect could be a result of weakened neighbouring molecule interactions and the changes in the conformation of lipid bilayers. This work provides important advances in understanding the mechanism by which NIPAM-based nanogels are able to interact with multi-bilayers, which can ultimately contribute to the development of novel nanoparticles able to interact and penetrate biological barriers.
Instrument: SURF, Inter
Related publication: “Interactions of NIPAM nanogels with model lipid multi-bilayers: A neutron reflectivity study.” Journal of Colloid and Interface Science 536,598-608 (2019).
Funding: European Commission, the Chinese Scholarship Council and Queen Mary, University of London.
Authors: H Sun, K Zielinska, M Resmini, A Zarbakhsh (Queen Mary, University of London)