INIDS2-1589
Charge-Conversion Chemistry for Effective Delivery of Keratin-Rebonding Materials into Hair Shafts
Topic
IDS2. Frontiers in Cosmetic Science and Technology (Sponsored by COSMAX)
When and Where
Sep 29, 2026
12:05 - 12:30
Room 102
Session Chairs
Hyosung AN
Presenter(s)
Yan Lee (Seoul National University)
Co-Author(s)
Abstract
Thiols in keratin are often over-oxidized into negatively charged sulfonates, significantly weakening the structural integrity of hair fibers. Although materials with multiple positive charges can form molecular bridges between these sulfonate groups to reinforce damaged hair, their strong electrostatic binding to the negatively charged surface of the hair shaft severely limits deep interior penetration.
To overcome this limitation, we applied the charge-conversion chemistry of β-carboxylic acid amides to deliver hair-rebonding agents deep into the hair shaft. These chemical moieties remain negatively charged at neutral pH but convert to cationic forms under mild acidification. Specifically, we synthesized various β-carboxylic acid amide derivatives of O,O'-bis(3-aminopropyl)diethylene glycol (BADG)—a representative hair-rebonding compound—with tunable negative charge density, hydrophobicity, and pH-responsive degradability. These engineered derivatives successfully penetrated deep into the hair shafts and facilitated re-bonding between sulfonate groups. Consequently, the treatment effectively restored the surface morphology and significantly enhanced the tensile strength of damaged hair fibers.Overall, these findings highlight charge-conversion chemistry as a promising strategy for delivering cationic bioactive agents into the deep interior of damaged hair.
