Facile anchoring mussel adhesive mimic tentacles on biodegradable polymer cargo carriers via self-assembly for microplastic-free cosmetics

Enhancing the deposition of fragrance delivery systems contained in personal care products on target surfaces is crucial for increasing the longevity of scent, efficiently utilizing expensive functional compounds and limiting the generation of microplastics in domestic waste water. In this work, we designed and synthesized a new type of biomimetic macromolecules, chitosan-graft-L-lysine-L-DOPA (C-L-D), as a versatile biodegradable adhesion promoter to facilitate the deposition of biodegradable fragrance carriers on diverse surfaces including hair, cotton and skin. The C-L-D has hyperbranched chain architecture with many oligopeptide adhesive tentacles, each being a simple mimic of mussel adhesive proteins. It also exhibits unique amphiphilic characteristic. As a result, it could be facilely anchored on cargo-loaded poly(lactic-co-glycolic acid) nanoparticle surface via self-assembly in the particle preparation process. The C-L-D-modified nanoparticles show significantly higher deposition efficiencies than polyvinyl alcohol- and chitosan-coated particles when deposited on the target surfaces in different aqueous media as the lysine and DOPA units are capable of providing multi-noncovalent interactions, including electrostatic, polar, hydrophobic interactions, and bidentate hydrogen bonds, with the target surfaces, and possibly also inducing oxidative cross-linking. A much higher retention rate of the C-L-D-modified nanoparticles on cotton surface is also observed after washing with a soap solution, which could be attributed to the significant role played by bidentate hydrogen bonds. These findings suggest that C-L-D is a versatile biodegradable adhesion promoter and has the potential to be applied for various personal care applications and beyond.