title: Electrochemical detection of biomolecule with mixed self-assembled monolayers of ferrocene-undecanethiol.
abstract: Thiol self-assembled monolayers (SAMs) have been widely used as a modification method to immobilize biomolecules to gold surfaces. However, the additional layers of SAM and biomolecules make electron transfer difficult, leading to a large overpotential in electrical signal. Electron transfer mediation is the most popular solution to overcome the problem of the overpotential for an electrochemical biosensor. We introduced mixed SAMs of mercapto-dodecanoic acid (MDA) and ferrocene-undecanthiol. Ferrocene-undecanthiol acts as an electron transfer mediator and MDA is used for immobilization of biomolecule. The electron transferability of mixed SAMs is affected by pH, kinds of electrolytes, and the composition of the thiol molecule. We optimized the carboxyl acid and ferrocene molecule ratio which is a crucial factor in the performance of mixed SAMs and electrochemically detected the avidin. The detection limit was 2.0 microg/mL of avidin concentration.
authors.affiliation: Molecular-Level Interface Research Center, Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Korea.
authors.forename: Seong Jung
authors.initials: SJ
authors.lastname: Kwon
authors.forename: Noeul
authors.initials: N
authors.lastname: Park
authors.forename: Dohyoung
authors.initials: D
authors.lastname: Kwon
authors.forename: Juhyoun
authors.initials: J
authors.lastname: Kwak
mesh_terms: D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D005296:Ferrous Compounds / Q000737:chemistry*; D000075163:Metallocenes; D013438:Sulfhydryl Compounds / Q000737:chemistry*
chemical_list: D005296:Ferrous Compounds; D000075163:Metallocenes; D013438:Sulfhydryl Compounds; C004998:ferrocene