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Engineering bioelectronic interfaces

How can we modify surfaces of inorganic electronics to make them suitable for biological applications?


Controlled Engineering of Oxide Surfaces for Bioelectronics Applications Using Organic Mixed Monolayers

Aleksandr Markov, Nikolaus Wolf, Xiaobo Yuan, Dirk Mayer, Vanessa Maybeck, Andreas Offenhäusser, and Roger Wördenweber

To appear in: ACS Appl. Mater. Interfaces, 2017

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DOI: 10.1021/acsami.7b08481

Engineering the bioelectronics interface.Schematic representation of mixed SAMs on the capacitive sensor structure and contour plot of the thickness of the mixed molecular monolayer determined via ellipsometry on SiO2-terminated Si substrates.

Modifying the surfaces of oxides using self- assembled monolayers offers an exciting possibility to tailor their surface properties for various applications ranging from organic electronics to bioelectronics applications. The simultaneous use of different molecules in particular can extend this approach because the surface properties can be tuned via the ratio of the chosen molecules. This requires the composition and quality of the monolayers to be controlled on an organic level, that is, on the nanoscale. In this paper, we present a method of modifying the surface and surface properties of silicon oxide by growing self-assembled monolayers comprising various compositions of two different molecules, (3-aminopropyl)-triethoxysilane and (3- glycidyloxypropyl)-trimethoxysilane, by means of in situ controlled gas-phase deposition. The properties of the resulting mixed molecular monolayers (e.g., effective thickness, hydrophobicity, and surface potential) exhibit a perfect linear dependence on the composition of the molecular layer. Finally, coating the mixed layer with poly(L-lysine) proves that the density of proteins can be controlled by the composition as well. This indicates that the method might be an ideal way to optimize inorganic surfaces for bioelectronics applications