Self‐assembled monolayers of mercaptosuccinic acid monolayers on silver and gold surfaces designed for protein binding. Part II: vibrational spectroscopy studies on cytochrome c immobilization

Abstract

An attempt has been made for using MSA-modified electrodes as linkage monolayers for electrostatic and covalent binding of cytochrome c (Cc). For MSA monolayers grown from an aqueous solution on Ag, attachment of Cc in its native state is proved in the case of covalent bonding. Electrostatic immobilization of Cc at pH 7 results in presence of at least some amount of Fe 2+ high-spin configuration and/or Fe 3+ oxidation state. Native protein Fe 2+ low-spin state of Cc is observed after applying a negative potential to the Ag electrode. The influence of the solvent used for the preparation of the MSA monolayer and thiol surface coverage of the Ag surface was studied. It was shown that the key factor to obtain the native structure of Cc is the successful blocking of the metal surface by the MSA linking layer. IRRAS measurements of MSA on monocrystalline gold (111) at neutral pH confirm the successful electrostatic Cc immobilization, which preserves the Fe 2+ oxidation state of the chromophore on this substrate.

Surface Chemistry of Thiomalic Acid Adsorption on Planar Gold and Gold Nanoparticles

“…1 In this regard, thiomalic acid (TMA) belongs to the hydrophilic thiols that can serve as adhesion layers for biomolecules 2 and cells to study their chemical and electrochemical reactivity at interfaces. Also, the TMA molecule is an intriguing choice to protect nanoparticles intended for biomedical applications because of its water solubility, biocompatibility, and in vivo stability.…”

“…In recent years, self-assembled monolayers (SAMs) of ω-terminated alkanethiols have been widely employed as linkage layers to electrostatically or covalently bind redox proteins to metal surfaces . In this regard, thiomalic acid (TMA) belongs to the hydrophilic thiols that can serve as adhesion layers for biomolecules and cells to study their chemical and electrochemical reactivity at interfaces. Also, the TMA molecule is an intriguing choice to protect nanoparticles intended for biomedical applications because of its water solubility, biocompatibility, and in vivo stability …”

Recent advances in linear and nonlinear Raman spectroscopy II

“…They also showed that in these methods, two different antibodies covalently bound to a solid substrate can specifically capture two different antigens from a sample. In two papers, Królikowska and Bukowska 15,16 studied SAMs of mercaptosuccinic acid (MSA) on silver and gold surfaces designed for protein binding. It was found 15 that at natural pH, MSA chemisorbs via a sulfur atom and one dissociated carboxylic group on the Ag and Au surface.…”

“…It was found 15 that at natural pH, MSA chemisorbs via a sulfur atom and one dissociated carboxylic group on the Ag and Au surface. In the second paper, 16 an attempt was made to use MSA-modified electrodes as linkage monolayers for electrostatic and covalent binding of cytochrome C (Cc). It was shown that the key factor to obtain the native structure of Cc is the successful blocking of the metal surface by the MSA linking layer.…”

Surface Engineering of Gold Nanorods for Cytochrome c Bioconjugation: An Effective Strategy To Preserve the Protein Structure

“…Recent studies have shown that the conformation of HCc adsorbed on Au NPs depends on surface coverage and NP size . To date, preservation of the native structure of HCc has been achieved on electrodes by using appropriate self-assembled monolayers, , but bioconjugation of colloidal Au NPs has mostly resulted in protein denaturation. ,− In particular, the conjugation of HCc to Au NPs has been found to preserve the HCc structure only when the structure has been decorated with aggregated Ag nanospheres . The bioconjugation of Au NRs with proteins is even more difficult.…”