title: Fe3O4nanoparticles on graphene oxide sheets for isolation and ultrasensitive amperometric detection of cancer biomarker proteins.
abstract: Ultrasensitive mediator-free electrochemical detection for biomarker proteins was achieved at low cost using a novel composite of Fe3O4nanoparticles loaded onto graphene oxide (GO) nano-sheets (Fe3O4@GO). This paramagnetic Fe3O4@GO composite (1µm size range) was decorated with antibodies against prostate specific antigen (PSA) and prostate specific membrane antigen (PSMA), and then used to first capture these biomarkers and then deliver them to an 8-sensor detection chamber of a microfluidic immunoarray. Screen-printed carbon sensors coated with electrochemically reduced graphene oxide (ERGO) and a second set of antibodies selectively capture the biomarker-laden Fe3O4@GO particles, which subsequently catalyze hydrogen peroxide reduction to detect PSA and PSMA. Accuracy was confirmed by good correlation between patient serum assays and enzyme-linked immuno-sorbent assays (ELISA). Excellent detection limits (LOD) of 15 fg/mL for PSA and 4.8 fg/mL for PSMA were achieved in serum. The LOD for PSA was 1000-fold better than the only previous report of PSA detection using Fe3O4. Dynamic ranges were easily tunable for concentration ranges encountered in serum samples by adjusting the Fe3O4@GO Concentration. Reagent cost was only $0.85 for a single 2-protein assay.
authors.affiliation: Department of Chemistry (U-3060), University of Connecticut, 55 North Eagleville Road, Storrs, CT 06269, USA; Analytical Chemistry Department, Faculty of Pharmacy, Zagazig University, Zakazik, Sharkia, Egypt.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Sharafeldin
authors.affiliation: Department of Chemistry (U-3060), University of Connecticut, 55 North Eagleville Road, Storrs, CT 06269, USA.
authors.forename: Gregory W
authors.initials: GW
authors.lastname: Bishop
authors.affiliation: Department of Chemistry (U-3060), University of Connecticut, 55 North Eagleville Road, Storrs, CT 06269, USA.
authors.forename: Snehasis
authors.initials: S
authors.lastname: Bhakta
authors.affiliation: Department of Chemistry (U-3060), University of Connecticut, 55 North Eagleville Road, Storrs, CT 06269, USA; Chemistry Department, Faculty of Science, Tanta University, Tanta, Egypt.
authors.forename: Abdelhamid
authors.initials: A
authors.lastname: El-Sawy
authors.affiliation: Department of Chemistry (U-3060), University of Connecticut, 55 North Eagleville Road, Storrs, CT 06269, USA; Institute of Materials Science, University of Connecticut, 97 North Eagleville Road, Storrs, CT 06269, USA.
authors.forename: Steven L
authors.initials: SL
authors.lastname: Suib
authors.affiliation: Department of Chemistry (U-3060), University of Connecticut, 55 North Eagleville Road, Storrs, CT 06269, USA; Institute of Materials Science, University of Connecticut, 97 North Eagleville Road, Storrs, CT 06269, USA; Department of Surgery and Neag Cancer Center, University of Connecticut Health Center, Farmington, CT 06032, USA; School of Chemistry, National University of Ireland, Galway, University Road, Galway, Ireland. Electronic address: James.Rusling@Uconn.edu.
authors.forename: James F
authors.initials: JF
authors.lastname: Rusling
mesh_terms: D055910:Antibodies, Immobilized / Q000737:chemistry; D000954:Antigens, Surface / Q000097:blood*; D014408:Biomarkers, Tumor / Q000097:blood; D015374:Biosensing Techniques / Q000295:instrumentation; D055664:Electrochemical Techniques / Q000295:instrumentation*; D004867:Equipment Design; D043425:Glutamate Carboxypeptidase II / Q000097:blood*; D006108:Graphite / Q000737:chemistry*; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation; D057230:Limit of Detection; D058185:Magnetite Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D008297:Male; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D049329:Nanostructures / Q000737:chemistry / Q000648:ultrastructure; D010087:Oxides / Q000737:chemistry; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood
chemical_list: D055910:Antibodies, Immobilized; D000954:Antigens, Surface; D014408:Biomarkers, Tumor; D058185:Magnetite Nanoparticles; D010087:Oxides; D006108:Graphite; C473848:FOLH1 protein, human; D043425:Glutamate Carboxypeptidase II; D017430:Prostate-Specific Antigen
keywords: Biomarker proteins; Graphene; Immunoarray; Iron oxide; Magnetic; Microfluidics