title: Effect of the Chain Length of a Modified Layer and Surface Roughness of an Electrode on Impedimetric Immunosensors.
abstract: An ultrasensitive label-free impedimetric immunosensor is constructed by modifying a 3-mercaptoproponic acid (MPA) monolayer on highly rough gold nanostructure (AuNS)-electrodeposited screen printed carbon electrodes (SPCEs) for the detection of small molecular weight drugs (SMWDs), such as salbutamol (SAL). The SPCEs preoxidized in a 0.1 M H2SO4solution (called po-SPCEH2SO4) are electrodeposited with the AuNS to increase the roughness factor to 23.64 ± 1.76, larger than the AuNS/po-SPCENaOHor the AuNS/po-SPCEPBS. Furthermore, the MPA modified layer as a link for the anti-SAL immobilization to give the immunosensors an impedimetric signal-to-noise ratio larger than the 11-mercapto-undecanoic acid- and 16-mercaptohexadecanoic acid-modified layer, due to the lower interfacial impedance of the MPA monolayer. The MPA/AuNS/po-SPCEH2SO4-based immunosensors have a wide linear range of 1 fg mL-1to 1 ng mL-1and a limit of detection of 0.6 fg mL-1. Moreover, the immunosensors can practically quantify the SAL concentrations in 1000 times-diluted serum samples with good recovery.
authors.affiliation: Department of Bio-industrial Mechatronics Engineering, National Chung Hsing University.
authors.forename: Chia-Hung
authors.initials: CH
authors.lastname: Lin
authors.forename: Ming-Jie
authors.initials: MJ
authors.lastname: Lin
authors.forename: Ching-Chou
authors.initials: CC
authors.lastname: Wu
mesh_terms: D015097:3-Mercaptopropionic Acid / Q000737:chemistry*; D000420:Albuterol / Q000032:analysis*; D002244:Carbon / Q000737:chemistry; D004566:Electrodes; D006046:Gold / Q000737:chemistry; D006801:Humans; D007118:Immunoassay; D049329:Nanostructures / Q000737:chemistry; D010316:Particle Size; D013464:Sulfuric Acids / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D013464:Sulfuric Acids; D002244:Carbon; D006046:Gold; D015097:3-Mercaptopropionic Acid; C033158:sulfuric acid; D000420:Albuterol