(180av) Vapor Deposited Multi-Conpoment Coatings for Bioorthogonal Conjugations

Bioorthogonal reactions fundamentally play important roles in fabricating a successful biointerface of biomaterials. Such reactions must offer the advantages of rapidity, specificity and more importantly, tolerance toward a diversified array of other functionality in their native environment or in the complexity of a living cell. As the quintessential example of click chemistry, the copper(I)-catalyzed Huisgen 1,3-dipolar cycloaddition of azides and terminal alkynes (CuAAC) has since been widely used as a surface modification strategy that offers advantages with high yields, rapidity, specificity and benign reaction conditions. Thiol-maleimide chemistry is also found to be a very efficient way to conjugate with thiol groups which plays an extraordinarily important role in biological system.  In this study, we report a direct synthesis of preparing hetero-bifunctional surfaces conatining both acetylene and maleimide reactive sites based on functionalized parylene coatings via chemical vapor deposition (CVD) copolymerization process, and the resulting copolymer coatings represent a prime tool to study and perform sophisticated mimicry of biointerfaces. X-ray photoelectron spectroscopy (XPS) and infrared reflection adsorption spectroscopy (IRRAS) are used to characterize the chemical structure of the hetero-bifunctional surfaces. In addition, these advanced coatings provide essentially (i) acetylene reactive groups that are readily clicked with azido molecules through CuAAC, (ii) maleimide sites that can undergo Michael-type addition to couple with thiol groups, and (iii) a multifunctional mimicry of interlayer that precisely interacts with complex biological system, e.g. cellular environment, and shown reaction specificity without cross-contamination.  Fluorescently labeled azides and cysteine molecules are used as exemplary models to verify the reactivities of the double click reactions in the study. Moreover, an application is showing by first controlling the fouling properties of the surface (first click), while the second control on the surface is shown on the manipulatation of bovine arterial endothelial cell (BAEC) adhesion (second click). We foresee the potential uses in biosensors, diagnostic devices, microfluidics, drug delivery, and tissue engineering.