Determination of Au Film Thiolation and Silane Bonding Onto SiO2 Films Within the Frame of Biosensor Surface Functionalization – an Analysis of Best Practices and Techniques

Abstract

This paper reviews some of the most common surface modification approaches in biosensing based on self-assembled monolayers with a particular focus on Au film thiolation and SiO2 film silanization. Such approaches are routinely used to alter the materials' surface properties towards a desired bioresponse. Furthermore, the most appropriate characterization methods towards ensuring successful surface modification are presented including XPS, HREELS, SPFS, Raman and FTIR spectroscopy as well as UPS with specific examples to demonstrate their importance. In addition, the mechanisms of fluorescent and non-fluorescent biotinylation of thiolated Au films and silanized SiO2 are discussed considering its importance in conjugating biomolecules such as enzymes, antibodies or chemokines onto surfaces, which carries high significance for biosensing applications. Finally, within this frame characterization routes towards ensuring effective attachment are discussed.

Thermal Stability and Orthogonal Functionalization of Organophosphonate Self-Assembled Monolayers as Potential Liners for Cu Interconnect

“…The former peak can be deconvoluted to three Si species, namely, Si 2p 1/2 (blue curve), Si 2p 3/2 (red curve), and Si 2 O (green curve) centered at 100, 99.4, − and 100.3 eV , binding energies, respectively. The latter broad peak in Figure d can be fitted into two Gaussian curves corresponding to the oxides of the substrates as in SiO 2 bonding at 103 eV , (cyan–blue curve) and the bonding between the organosilane Si and the inorganic silicon dioxide (Si sub –O–Si APTES ) centered at 102 eV (purple curve). ,, Based on our systematic optimization, we found that deposition at a low concentration (0.1%) and short immersion time (30 min) is optimal for yielding a 0.6 nm monolayer of APTES SAM based on ellipsometry measurement (Figure S1). Our result is consistent with both a recent report and the simulated molecular size of APTES obtained from the force fields function­(Figure S2).…”