title: Imidazolium-based ionic liquid surfaces for biosensing.
abstract: Ionic liquid self-assembled monolayers (SAM) were designed and applied for binding streptavidin, promoting affinity biosensing and enzyme activity on gold surfaces of sensors. The synthesis of 1-((+)-biotin)pentanamido)propyl)-3-(12-mercaptododecyl)-imidazolium bromide, a biotinylated ionic liquid (IL-biotin), which self-assembles on gold film, afforded streptavidin sensing with surface plasmon resonance (SPR). The IL-biotin-SAM efficiently formed a full streptavidin monolayer. The synthesis of 1-(carboxymethyl)-3-(mercaptododecyl)-imidazoliumbromide, a carboxylated IL (IL-COOH), was used to immobilize anti-IgG to create an affinity biosensor. The IL-COOH demonstrated efficient detection of IgG in the nanomolar concentration range, similar to the alkylthiols SAM and PEG. In addition, the IL-COOH demonstrated low fouling in crude serum, to a level equivalent to PEG. The IL-COOH was further modified with N,N'-bis (carboxymethyl)-l-lysine hydrate to bind copper ions and then, chelate histidine-tagged biomolecules. Human dihydrofolate reductase (hDHFR) was chelated to the modified IL-COOH. By monitoring enzyme activity in situ on the SPR sensor, it was revealed that the IL-COOH SAM improved the activity of hDHFR by 24% in comparison to classical SAM. Thereby, IL-SAM has been synthesized and successfully applied to three important biosensing schemes, demonstrating the advantages of this new class of monolayers.
authors.affiliation: Département de Chimie, Université de Montréal, C.P. 6128 Succ. Centre-Ville, Montreal, Quebec, Canada H3C 3J7.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Ratel
authors.forename: Audrey
authors.initials: A
authors.lastname: Provencher-Girard
authors.forename: Sandy Shuo
authors.initials: SS
authors.lastname: Zhao
authors.forename: Julien
authors.initials: J
authors.lastname: Breault-Turcot
authors.forename: Jérémie
authors.initials: J
authors.lastname: Labrecque-Carbonneau
authors.forename: Mathieu
authors.initials: M
authors.lastname: Branca
authors.forename: Joelle N
authors.initials: JN
authors.lastname: Pelletier
authors.forename: Andreea R
authors.initials: AR
authors.lastname: Schmitzer
authors.forename: Jean-Francois
authors.initials: JF
authors.lastname: Masson
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D006801:Humans; D007093:Imidazoles / Q000737:chemistry*; D052578:Ionic Liquids / Q000737:chemistry*; D020349:Surface Plasmon Resonance / Q000379:methods
chemical_list: D007093:Imidazoles; D052578:Ionic Liquids