A disposable Protein A-based immunosensor for flow-injection assay with electrochemical detection

Development of an Amperometric Immunosensor for the Quantification of Staphylococcus aureus Using Self‐Assembled Monolayer‐Modified Electrodes as Immobilization Platforms

“…Rishpon et al [8] described a disposable amperometric, enzyme channeling immunosensor, which they used for the determination of S. aureus in pure culture through an amperometric immunoassay in a sandwich configuration. Moreover, some other protein Abonded immunosensors have been described [11,1,2], but they were not used for the S. aureus quantification. Also, a study on Staphylococcus aureus adhesion to alkanethiol selfassembled monolayers (SAMs) has been reported [12], concluding that the attachment of bacteria to SAMs increases linearly with time, and that hydrophobic CH 3 and the COOH SAM have the highest S. aureus adhesion.…”

Recent Advances in Electrochemical Enzyme Immunoassays

“…Although several strategies have been developed to overcome this random orientation and focus on the sitedirected immobilization of immunoreagents, such as the application of a potential [161] during adsorption, or the attachment of half-IgG fragments [162] through their native thiol groups on gold surfaces, the most commonly strategies used to obtain an oriented immunoreagent immobilization are: binding to Fc receptors such as Proteins A or G [101,109,146] on the electrode surface; binding of other binding partners to structures, e.g. the biotin residue on the Fc binds to surface-coated (strept)avidin [104,112,145,147,148]; and binding through an immunological reaction [148 -150].…”

“…A simplification on the assay procedure in terms of operator intervention can be achieved coupling immunosensor devices with flow systems [91,109,137,138,142,146,149,155]. Working with a flow system the procedure can be automated and the analysis performed continuously and quickly, but the systems become instrumentally more complex and none of the assay steps are removed.…”

“…The second strategy is most frequently used, but also requires the use of extreme pH solutions such as citric acid [146], NaOH À NaCl pH 12 [158,159] , citrate -phosphate pH 4.6 [110], phosphate pH 2.1 [109], pepsin pH 2.1 [155] or fluoride acid [160].…”

Imunossensor amperométrico

“…Portanto, ao propiciar a imobilização pela fração Fc, permite-se uma orientação adequada do anticorpo imobilizado obtendo-se sítios ligantes direcionados para a solução contendo a amostra ou padrão. O uso de proteínas que orientem a imobilização dos anticorpos, como a proteína A 15 e proteína G 16 , a imobilização através de monocamadas formadas pelo método Langmuir-Blodgett 18 ou via tiocompostos 18 são os ideais sob o ponto de vista do acesso do antígeno para a reação de afinidade.…”