title: A sensitive capacitive immunosensor for direct detection of human heart fatty acid-binding protein (h-FABP).
abstract: The fabrication of a capacitive interdigitated immunosensor (CID) based on a mixed self-assembled monolayer (mSAM) film for the direct detection of heart fatty-acid binding protein (h-FABP) without any labeling is described. The capacitance changes of mSAMs vs. homogenous ordered self-assembled monolayers (hSAMs) on gold work electrodes/covalently bonded antibodies/buffered medium are utilized for monitoring the specific antibody-antigen interaction. Capacitance measurements in the absence and presence of Faradaic currents were performed. The electrochemical properties of mixed monolayers were compared with those of a pure monolayer of 11-mercaptoundecanoic acid (MUA) self-assembled on gold surfaces. Taking into account the stability of the studied monolayers during the electrochemical experiments with the Faradaic process, the best SAM functionalization method was used for developing a sensitive capacitive immunosensor with a non-Faradaic process for direct immune detection of human h-FABP. Under the optimized conditions, the proposed mixed self-assembled monolayer (mSAM1) on gold electrode exhibited good insulating properties such as a capacitive behavior when detecting h-FABP from human serum in the range of 98 pg ml(-1)-100 ng ml(-1), with a detection limit of 0.836 ng ml(-1) comparative with a homogenous self-assembled monolayer (hSAM).
authors.affiliation: Department of Physical Chemistry, Faculty of Chemistry, University of Bucharest, Bd. Regina Elisabeta, No. 4-12, Bucharest, Romania. Electronic address: carmen_mihailescu1234@yahoo.com.
authors.forename: Carmen-Marinela
authors.initials: CM
authors.lastname: Mihailescu
authors.affiliation: DDS Diagnostic, Gh. Sincai Street no. 9A, 040312 Bucharest, Romania.
authors.forename: Dana
authors.initials: D
authors.lastname: Stan
authors.affiliation: National Institute for R&D in Microtechnologies (IMT), 126A Erou Iancu Nicolae, 077190 Bucharest, Romania.
authors.forename: Rodica
authors.initials: R
authors.lastname: Iosub
authors.affiliation: National Institute for R&D in Microtechnologies (IMT), 126A Erou Iancu Nicolae, 077190 Bucharest, Romania.
authors.forename: Carmen
authors.initials: C
authors.lastname: Moldovan
authors.affiliation: Telemedica, Str. Ion Calin, No. 13, Bucharest, Romania. Electronic address: mihaelasvn@yahoo.com.
authors.forename: Mihaela
authors.initials: M
authors.lastname: Savin
mesh_terms: D000818:Animals; D000906:Antibodies / Q000737:chemistry; D025802:Electric Capacitance; D055664:Electrochemical Techniques / Q000295:instrumentation*; D004566:Electrodes; D050556:Fatty Acid-Binding Proteins / Q000097:blood*; D005227:Fatty Acids / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation*; D057230:Limit of Detection; D051379:Mice; D009206:Myocardium / Q000737:chemistry*; D015203:Reproducibility of Results; D013438:Sulfhydryl Compounds / Q000737:chemistry
chemical_list: C505222:11-mercaptoundecanoic acid; D000906:Antibodies; D050556:Fatty Acid-Binding Proteins; D005227:Fatty Acids; D013438:Sulfhydryl Compounds; D006046:Gold
keywords: Acute myocardial infarction; Capacitive immunosensor; Cardiac marker; Self-assembled monolayer; h-FABP