Multifunctional Catechol/Catecholamine Coatings
We are developing a family of coatings by exploiting the chemical diversity of catechols for attachment onto many different organic and inorganic surfaces, and for conferring a variety of functional uses. In a landmark paper (Science, 2007), we reported the formation of coatings from alkaline oxidative polymerization of dopamine. These "polydopamine" coatings are simple to apply through a dip-coating process, have thickness ranging from a few nm to >100nm and deposit on virtually any material surface (Figure). Polydopamine coatings further act as primers for deposition of secondary coatings such as antifouling or cell-adhesive polymers, immobilized biomolecules, conformal metal films, self-assembled monolayers, etc.
Some examples of practical applications of polydopamine-based coatings being pursued by our group include:
We have developed a number of other catechol/catecholamine polymers for surface modification. In one case, the strategies of mussel and gecko adhesion were combined in a unique way to form a temporary adhesive capable of adhering to wet or dry surfaces in a reversible manner. The fibrillar structures found on the gecko foot hairs were mimicked by fabricating an array of pillars on an elastomeric material using nanolithography. The surface of the structured silicone elastomer was then coated by a thin film of mussel mimetic polymer (Figure). This tape-like adhesive material, which borrows the geometric pillar structure from the gecko and the wet adhesive surface chemistry from the mussel, was capable of reversible attachment to surfaces in both dry and wet conditions.