Programmable Control of Active Ingredient Release in Pickering Emulsions Using Light.

Summary

The authors engineer azobenzene-functionalized silica at emulsion interfaces to create light-gated “nanogates” that open under UV and close under visible light, enabling programmable release of a model cargo (perylene) while retaining emulsion stability. Release can be tuned by particle size and irradiation time, offering a non-invasive, remote-controlled platform relevant to cosmetic actives.

Key Findings

• Light-gated nanogates at oil–water interfaces enable programmable release from Pickering emulsions.
• UV induces gate opening via azobenzene cis–trans isomerization; visible light closes gates.
• Release amount is tunable by colloidal particle size and UV/visible exposure duration.
• Emulsion stability is maintained during repeated light cycling.

Clinical Implications

While preclinical, this platform could enable photo-triggered release of actives (e.g., antioxidants, fragrances) from topical formulations. Safety considerations (UV dose, phototoxicity) and shift to visible/NIR triggers will be needed for dermatologic use.

Limitations

• Demonstrated with a model hydrophobic cargo (perylene); no bioactive or in vivo data
• UV triggering raises safety/skin phototoxicity concerns; scalability and biocompatibility not evaluated

Future Directions

Translate the nanogate design to visible/NIR-responsive chemistries, test with clinically relevant cosmetic actives, and evaluate biocompatibility and skin penetration in ex vivo/clinical models.