2017, Riedel, Tomáš, Hageneder, Simone, Surman, František, Pop-Georgievski, Ognen, Noehammer, Christa, Hofner, Manuela, Brynda, Eduard, Rodriguez-Emmenegger, Cesar, Dostálek, Jakub

A biosensor for the detection of hepatitis B antibodies in clinical saliva was developed. Compared to conventional analysis of blood serum, it offers the advantage of noninvasive collection of samples. Detection of biomarkers in saliva imposes two major challenges associated with the low analyte concentration and increased surface fouling. The detection of minute amounts of hepatitis B antibodies was performed by plasmonically amplified fluorescence sandwich immunoassay. To have access to specific detection, we prevented the nonspecific adsorption of biomolecules present in saliva by brushes of poly[(N-(2-hydroxypropyl) methacrylamide)-co-(carboxybetaine methacrylamide)] grafted from the gold sensor surface and post modified with hepatitis B surface antigen. Obtained results were validated against the response measured with ELISA at a certified laboratory using serum from the same patients. © 2017

2017, Buzzacchera, Irene, Vorobii, Mariia, Kostina, Nina Yu, de Los Santos Pereira, Andres, Riedel, Tomáš, Bruns, Michael, Ogieglo, Wojciech, Möller, Martin, Wilson, Christopher J., Rodriguez-Emmenegger, Cesar

Implantable sensor devices require coatings that efficiently interface with the tissue environment to mediate biochemical analysis. In this regard, bioinspired polymer hydrogels offer an attractive and abundant source of coating materials. However, upon implantation these materials generally elicit inflammation and the foreign body reaction as a consequence of protein fouling on their surface and concomitant poor hemocompatibility. In this report we investigate a strategy to endow chitosan hydrogel coatings with antifouling properties by the grafting of polymer brushes in a "grafting-from" approach. Chitosan coatings were functionalized with polymer brushes of oligo(ethylene glycol) methyl ether methacrylate and 2-hydroxyethyl methacrylate using photoinduced single electron transfer living radical polymerization and the surfaces were thoroughly characterized by XPS, AFM, water contact angle goniometry, and in situ ellipsometry. The antifouling properties of these new bioinspired hydrogel-brush coatings were investigated by surface plasmon resonance. The influence of the modifications to the chitosan on hemocompatibility was assessed by contacting the surfaces with platelets and leukocytes. The coatings were hydrophilic and reached a thickness of up to 180 nm within 30 min of polymerization. The functionalization of the surface with polymer brushes significantly reduced the protein fouling and eliminated platelet activation and leukocyte adhesion. This methodology offers a facile route to functionalizing implantable sensor systems with antifouling coatings that improve hemocompatibility and pave the way for enhanced device integration in tissue.