title: Reduced graphene oxide field-effect transistor for label-free femtomolar protein detection.
abstract: We report reduced graphene oxide field effect transistor (R-GO FET) biosensor for label-free ultrasensitive detection of a prostate cancer biomarker, prostate specific antigen/α1-antichymotrypsin (PSA-ACT) complex. The R-GO channel in the device was formed by reduction of graphene oxide nanosheets networked by a self-assembly process. Immunoreaction of PSA-ACT complexes with PSA monoclonal antibodies on the R-GO channel surface caused a linear response in the shift of the gate voltage, V(g,min), where the minimum conductivity occurs. The R-GO FET can detect protein-protein interactions down to femtomolar level with a dynamic range over 6-orders of magnitude in the V(g,min) shift as a sensitivity parameter. High association constants of 3.2 nM(-1) and 4.2 nM(-1) were obtained for the pH 6.2 and pH 7.4 analyte solutions, respectively. The R-GO FET biosensor showed a high specificity to other cancer biomarker in the phosphate buffered saline solutions as well as in the human serum.
authors.affiliation: Department of Advanced Materials Science & Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do 440-746, Korea.
authors.forename: Duck-Jin
authors.initials: DJ
authors.lastname: Kim
authors.forename: Il Yung
authors.initials: IY
authors.lastname: Sohn
authors.forename: Jin-Heak
authors.initials: JH
authors.lastname: Jung
authors.forename: Ok Ja
authors.initials: OJ
authors.lastname: Yoon
authors.forename: N-E
authors.initials: NE
authors.lastname: Lee
authors.forename: Joon-Shik
authors.initials: JS
authors.lastname: Park
mesh_terms: D014408:Biomarkers, Tumor / Q000097:blood*; D015374:Biosensing Techniques / Q000295:instrumentation; D045744:Cell Line, Tumor; D003217:Conductometry / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006108:Graphite / Q000737:chemistry*; D006801:Humans; D009363:Neoplasm Proteins / Q000097:blood*; D009374:Neoplasms, Experimental / Q000097:blood* / Q000175:diagnosis; D010087:Oxides / Q000737:chemistry; D025941:Protein Interaction Mapping / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013194:Staining and Labeling; D014173:Transistors, Electronic
chemical_list: D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins; D010087:Oxides; D006108:Graphite