Sustaining guest molecules on bio-surfaces by grafting the surfaces with cyclodextrins

Grafting cyclodextrins (CDs) onto materials is an interesting approach to provide the remarkable ability of CDs to form an inclusion complex with various guest molecules onto other (bio)materials. Here we show the design, synthesis and characterization of "a ready to graft β-CD", which is a cyclodextrinyl methacrylate (M-β-CD), which will easily attach covalently to thiol-containing materials via a simple Michael thiol-ene click reaction under a biologically mild condition. Reacting M-β-CD with soluble keratin, human hair and a mucin layer as model biomaterials, in the presence of either tris (2-carboxyethyl) phosphine or vitamin C, resulted in β-CD-grafted keratin that displayed a controlled release of 8-anilino-1-naphthalenesulfonic acid, and both β-CD-grafted-hair strands and β-CD-grafted-mucin layers that effectively retained curcumin. Although this was demonstrated with β-CD on these three biomaterials, this platform could theoretically equally be used with other CDs to give a different range of guest material complexation, and be able to be applied to other thiol-containing materials.