Dual Responsive\nEmulsions Based on Amphiphilic Elastin-like\nPolypeptide Bioconjugates

To achieve the desired therapeutic response, drug delivery\nsystems\nmust ensure the controlled release of the loaded content at the targeted\nsite. One possible strategy relies on the improvement of conventional\ndrug delivery systems. To do so, smart polymers, able to change their\nbehavior upon chemical, physical, or biological stimuli, can be used.\nIn this context, this study aims to evaluate the potential of natural\namphiphilic smart elastin-like polypeptides grafted with alkyl chains\n(ELP-<i>g</i>-Bu) to stabilize conventional oil-in-water\nemulsions and trigger the release of loaded molecules upon dual stimuli.\nWith butyl pendant chains and methionine residues, the macromolecular\nsurfactant ELP-<i>g</i>-Bu demonstrated a modification of\nphysicochemical properties, looking at critical aggregation concentration,\nupon both temperature and oxidation stimuli. The macromolecular surfactant\nwas then able to stabilize a paraffin-oil-in-water emulsion. The ELP-<i>g</i>-Bu emulsion presented a droplet size of 9 ± 1 μm\nand stability for at least a month at 4 and 25 °C. After successful\nloading of a fluorescent lipophilic molecule used as a drug model,\na complete destabilization of the ELP-<i>g</i>-Bu emulsion\nand burst release of the content was achieved with thermal triggering\nat 42 °C. In oxidative conditions, a partial release was measured,\nwhich can be improved by increasing the number of oxidable thioether\ngroups. Overall, these dually responsive amphiphilic ELP-<i>g</i>-Bu demonstrated their potential for smart-polymer-based drug delivery\nsystems that can be promising for inflammatory disease treatment as\nincreased temperature and radical oxygen species are present in such\ncases.