(175d) Vapor-Based Reactive Polymer Coatings: A Robust Tool for Biointerface Engineering
Reactive polymers can be synthesized via chemical vapor deposition (CVD) polymerization. The resulting ultra-thin coatings are pinhole-free and can be conformally deposited to a wide range of substrates and materials. More importantly, the equipped functional groups can serve as anchoring sites for tailoring the surface properties, making these reactive coatings a robust platform to deal with sophisticated challenges faced in biointerfaces. These advanced coatings can improve the interfacial biocompatibility of biomedical surfaces or can be compatible with complex biological features as they represent a designable interlayer; stable under the conditions of the biological environments. By using a photodefinable coating, polyethylene oxides were immobilized onto a wide range of substrates through photo-immobilization. Spatially controlled protein resistant properties were characterized by selective adsorption of fibrinogen and bovine serum albumin as model systems. Alternatively, surface initiator coatings were used for polymer graftings of poly(ethylene glycol) methyl ether methacrylate, and the resultant protein- and cell- resistant properties were characterized by adsorption of kinesin motor proteins, fibrinogen, and murine fibroblasts (NIH3T3). On the other hand, accessibility of reactive coatings within confined microgeometries was systematically studied, and the preparation of homogeneous polymer thin films within the inner surface of microchannels was demonstrated. Moreover, these advanced coatings were applied to develop a dry adhesion process for microfluidic devices. This process provides (i) excellent bonding strength, (ii) extended storage time prior to bonding, and (iii) well-defined surface functionalities for subsequent surface modifications. Finally, surface microstructures and surface patterns using reactive coatings via photopatterning, projection lithography, supramolecular nanostamping (SuNS), vapor-assisted micropatterning in replica structures (VAMPIR), and dip-pen nanolithography (DPN) are introduced. These patterning techniques can be complimentarily used and provide access to precisely confined microenvironments on flat and curved geometries regardless of the underlying material used. Reactive coatings provide a technology platform that creates active, long-term control and may lead to improved mimicry of biological systems for effective bio-functional modifications.