Reduced graphene oxide field-effect transistor for label-free femtomolar protein detection

• Published in: Biosensors & bioelectronics Vol. 41; pp. 621 - 626
• Main Authors: Kim, Duck-Jin, Sohn, Il Yung, Jung, Jin-Heak, Yoon, Ok Ja, Lee, N.-E., Park, Joon-Shik
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15.03.2013; Elsevier
• Subjects: Biological and medical sciences; Biomarkers, Tumor - blood; Biosensing Techniques - instrumentation; Biosensor; Biosensors; Biotechnology; Cell Line, Tumor; Conductometry - instrumentation; Equipment Design; Equipment Failure Analysis; Field-effect transistor; Fundamental and applied biological sciences. Psychology; Graphite - chemistry; Humans; Immunosensing; Label-free detection; Methods. Procedures. Technologies; Neoplasm Proteins - blood; Neoplasms, Experimental - blood; Neoplasms, Experimental - diagnosis; Oxides - chemistry; Protein Interaction Mapping - instrumentation; Reduced graphene oxide; Reproducibility of Results; Sensitivity and Specificity; Staining and Labeling; Transistors, Electronic; Various methods and equipments; Reduced graphene oxide; Immunosensing; Label-free detection; Field-effect transistor; Biosensor; Field effect transistor; Graphene; Detection; Immunosensor; Protein
• DOI: 10.1016/j.bios.2012.09.040
• ISSN: 0956-5663

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, Vg,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 Vg,min shift as a sensitivity parameter. High association constants of 3.2nM−1 and 4.2nM−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. ► R-GO FFET was applied to the ultrasensitive detection of cancer biomarkers. ► Residue-free R-GO channel in the FET enables femtomolar detection of proteins. ► The change of charge neutrality point shows a good linearity and large dynamic range.