Michael-type addition as a tool for surface functionalization.

Michael-type addition (conjugate addition reaction between electron-poor olefins and nucleophiles, such as thiols) has been successfully used as a convenient tool for surface functionalization. Due to its mild character, this method is potentially useful for the introduction of sensitive groups, which can provide bioactivity and targeting possibilities to surfaces of, for example, colloidal carriers. As reaction partners, in our study we have used thiols, possibly present in peptidic structures, and acrylates, at the end of protein-repellant PEG chains. Satisfactory results were obtained with thiols in solution and acrylic groups bound to the surface. Alternatively, the use of thiols on the particles, even if generated in situ, did not provide useful results.