title: Redox and label-free array detection of protein markers in human serum.
abstract: A substantial outstanding challenge in diagnostics and disease monitoring is an ability to rapidly and conveniently assay for protein biomarkers within complex biological media. Label-free electroanalytical methods present, arguably, the most promising and scalable means of achieving this but, as with all label-free assays, can struggle with response selectivity issues that arise from nonspecific surface interactions. Impedimetric methods are ultrasensitive and have been applied to the quantification of a wide range of proteins but have not previously been utilized in a multiplexed format capable of operation in complex analytical fluid. Herein, we present the use of thermally cross-linked poly(ethylene glycol) (PEG) polymer sensory array interfaces in the ultrasensitive quantification of two protein markers, insulin and C-reactive protein (CRP). This was achieved with detection limits of 171 ± 19 fM and 150 ± 10 pM, respectively. Significantly, the arrays not only enable the simultaneous, fast, nonamplified, and label-free detection of both markers without reagent addition but do so with little cross talk, even in human serum. A blind analysis of 17 real patient samples generated results in excellent agreement with those obtained through a clinically approved chemiluminescence assay.
authors.affiliation: Key Laboratory of Biochemical Analysis, Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology , Qingdao 266042, China.
authors.forename: Xiliang
authors.initials: X
authors.lastname: Luo
authors.forename: Qiao
authors.initials: Q
authors.lastname: Xu
authors.forename: Tim
authors.initials: T
authors.lastname: James
authors.forename: Jason J
authors.initials: JJ
authors.lastname: Davis
mesh_terms: D000906:Antibodies / Q000737:chemistry; D015415:Biomarkers / Q000032:analysis*; D001798:Blood Proteins / Q000032:analysis*; D002097:C-Reactive Protein / Q000032:analysis; D004563:Electrochemistry; D006801:Humans; D007328:Insulin / Q000032:analysis; D049449:Luminescence; D010084:Oxidation-Reduction; D011092:Polyethylene Glycols; D044967:Serum / Q000737:chemistry
chemical_list: D000906:Antibodies; D015415:Biomarkers; D001798:Blood Proteins; D007328:Insulin; D011092:Polyethylene Glycols; D002097:C-Reactive Protein