Antifouling Studies of Unsymmetrical Oligo(ethylene glycol) Spiroalkanedithiol Self-Assembled Monolayers

Abstract

The antifouling properties of self-assembled monolayers (SAMs) on gold generated from custom-designed bidentate unsymmetrical spiroalkanedithiols containing both oligo(ethylene glycol) and hydrocarbon tailgroups (EG3C7-C7 and EG3C7-C18) were evaluated and compared to SAMs derived from analogous monodentate octadecanethiol (C18SH) and the tri(ethylene glycol)-terminated alkanethiol EG3C7SH. Complementary techniques, including in situ surface plasmon resonance spectroscopy (SPR), ex situ electrochemical quartz crystal microbalance (QCM) measurements, and ex situ ellipsometric thickness measurements, were employed to assess the protein resistance of the SAMs using proteins having a wide range of sizes, structures, and properties: protamine, lysozyme, bovine serum albumin (BSA), and fibrinogen. The studies found that SAMs generated from the bidentate adsorbates EG3C7-C7 and EG3C7-C18, which contain a 1:1 mixture of OEG and hydrocarbon tailgroups, exhibited a diminished capacity to resist protein adsorption compared to the EG3C7SH SAMs, which possess only OEG tailgroups. The data highlight the critical role of hydration of the OEG matrix for generating antifouling OEG-based surface coatings.

Functionalized N-Heterocyclic Carbene Monolayers on Gold for Surface-Initiated Polymerizations

“…First, organothiol SAMs on gold are easy to form, well defined, and well studied . Second, SAMs on gold offer surfaces composed of readily selectable chemical functionalities depending on the terminal species of the adsorbate used, which can be used to tune the interfacial properties in a controllable fashion. − Moreover, organic SAMs on gold have the capacity to utilize surface plasmon resonance (SPR) effects for useful applications (e.g., in biosensing) . Thus, surface modifications, including polymerizations via SAM formation, have been investigated mainly using thiol absorbates, despite the instability of Au–S bonds at temperatures higher than ∼80 °C and under oxidizing conditions. − …”

Carbonate-Terminated Self-Assembled Monolayers for Mimicking Nanoscale Polycarbonate Surfaces

“…Organic thin films have been widely used materials for modifying the interfacial properties of various surfaces. These nanoscale films, in the form of self-assembled monolayers (SAMs), have been utilized in various applications such as lubricants for microelectromechanical systems, catalyst modifiers for hydrogenation reactions, , anti-corrosion protectants for metal surfaces, , and anti-adhesive films for surfaces and biosensors − due to their facile generation and manipulation. In further efforts to generate nanoscale films that mimic the surfaces of industrial polymers, , this paper describes the preparation of SAMs derived from the adsorption of alkanethiols terminated with 1,3-dioxane-2-one moieties on gold to serve as mimics to the surfaces of commercially available poly­(propylene carbonate) (PPC) and poly­(ethylene carbonate) (PEC).…”

Sum frequency generation spectroscopy of fluorinated organic material-based interfaces: a tutorial review

“…24–29 Numerous solid–liquid and solid–air interfaces have been investigated using these model surfaces composed of self-assembled and chemically bound molecules on a surface due to the monolayers’ ability to mimic the physical properties of more complex systems. 5,30–33 These monolayer thin films have been used in a wide variety of applications, including biologically relevant surfaces, 34–38 lubricants for microelectromechanical systems (MEMs), 39–41 and corrosion inhibitors. 42–47…”