title: Redox-tagged peptide for capacitive diagnostic assays.
abstract: Early detection assays play a key role in the successful treatment of most diseases. Redox capacitive biosensors were recently introduced as a potential electroanalytical assay platform for point-of-care applications but alternative surfaces (besides a mixed layer containing ferrocene and antibody receptive component) for recruiting important clinical biomarkers are still needed. Aiming to develop alternative receptive surfaces for this novel electrochemical biosensing platform, we synthesized a ferrocene redox-tagged peptide capable of self-assembly into metallic interfaces, a potentially useful biological surface functionalization for bedside diagnostic assays. As a proof of concept we used C-reactive protein (CRP), as a model biomarker, and compared the obtained results to those of previously reported capacitive assays. The redox-tagged peptide approach shows a limit of detection of 0.8 nmol L(-1) (same as 94 ng mL(-1)) and a linear range (R(2)∼98%) with the logarithm of the concentration of the analyte comprising 0.5-10.0 nmol L(-1), within a clinical relevant range for CRP.
authors.affiliation: Department of Physical Chemistry, Chemistry Institute, São Paulo State University (UNESP, Universidade Estadual Paulista), Nanobionics Research Group, 55 Prof. Francisco Degni Street, 14800-060 Araraquara, São Paulo, Brazil(2).
authors.forename: Adriano
authors.initials: A
authors.lastname: Santos
authors.affiliation: Department of Physical Chemistry, Chemistry Institute, São Paulo State University (UNESP, Universidade Estadual Paulista), Nanobionics Research Group, 55 Prof. Francisco Degni Street, 14800-060 Araraquara, São Paulo, Brazil(2).
authors.forename: Julia P
authors.initials: JP
authors.lastname: Piccoli
authors.affiliation: Department of Physical Chemistry, Chemistry Institute, São Paulo State University (UNESP, Universidade Estadual Paulista), Nanobionics Research Group, 55 Prof. Francisco Degni Street, 14800-060 Araraquara, São Paulo, Brazil(2).
authors.forename: Norival A
authors.initials: NA
authors.lastname: Santos-Filho
authors.affiliation: Department of Physical Chemistry, Chemistry Institute, São Paulo State University (UNESP, Universidade Estadual Paulista), Nanobionics Research Group, 55 Prof. Francisco Degni Street, 14800-060 Araraquara, São Paulo, Brazil(2).
authors.forename: Eduardo M
authors.initials: EM
authors.lastname: Cilli
authors.affiliation: Department of Physical Chemistry, Chemistry Institute, São Paulo State University (UNESP, Universidade Estadual Paulista), Nanobionics Research Group, 55 Prof. Francisco Degni Street, 14800-060 Araraquara, São Paulo, Brazil(2). Electronic address: prbueno@iq.unesp.br.
authors.forename: Paulo R
authors.initials: PR
authors.lastname: Bueno
mesh_terms: D015374:Biosensing Techniques; D002097:C-Reactive Protein / Q000737:chemistry / Q000302:isolation & purification*; D006801:Humans; D057230:Limit of Detection; D009842:Oligopeptides / Q000737:chemistry; D010084:Oxidation-Reduction
chemical_list: D009842:Oligopeptides; C037841:tyrosyl-alanyl-glycine; D002097:C-Reactive Protein
keywords: Binding affinity constant; Electrochemical capacitance spectroscopy; Ferrocene-tagged peptide; Label-free redox capacitance biosensing