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

Abstract

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.

Mechanical and Electronic Cell–Chip Interaction of APTES-Functionalized Neuroelectronic Interfaces

“…Alternatively one can use a thin coating with chemically bound molecules. For example, the functionalization of conventional surfaces like SiO 2 via silanization represents a well-known technology for Si-based surfaces. − In this approach, silanes bind covalently with their headgroup to the substrate, typically SiO 2 , and in the ideal case form extremely thin and stable self-assembled monolayers (SAM) of approximately 1 nm in thickness. The properties of the new surface are then modified by the functional group of the silane.…”

Super-Nernstian pH Sensor Based on Anomalous Charge Transfer Doping of Defect-Engineered Graphene

“…We assumed d to be 0.8 nm, which is the average thickness of APTES (see Figure S9 in Supporting Information), and ε r,APTES as 6. 54 The energy that can affect the charge within the graphene channel by one external charge is 2.41 × 10 −18 eV. In the case of the charge transfer doping, the change in Fermi energy (E F ) due to the impurity charge carrier is defined as 55…”

“…Accordingly, the electrostatic energy ( U ) given to a graphene channel by an external electron is defined as In eq , q is the amount of charge given by one charge, and Φ is the electric potential produced by the external electron, defined by the parallel capacitor model: where d is the distance between the graphene channel and the external electron, ε 0 is the vacuum permittivity defined as 8.85 × 10 –12 F/m, and ε r is the relative permittivity. We assumed d to be 0.8 nm, which is the average thickness of APTES (see Figure S9 in Supporting Information), and ε r,APTES as 6 . The energy that can affect the charge within the graphene channel by one external charge is 2.41 × 10 –18 eV.…”

Improvements of Microcontact Printing for Micropatterned Cell Growth by Contrast Enhancement

“…In this step, the silane backbone of the Glymo should bind to the hydroxyl groups of the activated glass, as seen in Figure 4a, in a condensation reaction [44]. Also, the silane groups of the individual Glymo molecules interconnect to form a stable monolayer [45]. Next, PLL was microcontact printed onto the Glymo layer with POP stamps, which allows for a reaction between the amino group of PLL and Glymo’s epoxy group [1].…”