title: Detection of clinically relevant levels of protein analyte under physiologic buffer using planar field effect transistors.
abstract: Electrochemical detection of protein binding at physiological salt concentration by planar field effect transistor platforms has yet to be documented convincingly. Here we report detection of streptavidin and clinically relevant levels of biotinylated monokine induced by interferon gamma (MIG) at physiological salt concentrations with AlGaN heterojunction field effect transistors (HFETs). The AlGaN HFETs are functionalized with a silane linker and analyte-specific affinity elements. Polarity of sensor responses is as expected from n-type HFETs to negatively and positively charged analytes. Sensitivity of the HFET sensors increases when salt concentration decreases, and the devices also exhibit dose-dependent responses to analyte. Detection of clinically relevant MIG concentrations at physiological salt levels demonstrates the potential for AlGaN devices to be used in development of in vivo biosensors.
authors.affiliation: The Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA.
authors.forename: Samit
authors.initials: S
authors.lastname: Gupta
authors.forename: Mark
authors.initials: M
authors.lastname: Elias
authors.forename: Xuejin
authors.initials: X
authors.lastname: Wen
authors.forename: John
authors.initials: J
authors.lastname: Shapiro
authors.forename: Leonard
authors.initials: L
authors.lastname: Brillson
authors.forename: Wu
authors.initials: W
authors.lastname: Lu
authors.forename: Stephen Craig
authors.initials: SC
authors.lastname: Lee
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D054370:Chemokine CXCL9 / Q000032:analysis* / Q000737:chemistry; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006863:Hydrogen-Ion Concentration; D007118:Immunoassay / Q000295:instrumentation* / Q000379:methods; D008839:Microelectrodes; D025941:Protein Interaction Mapping / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D019809:Streptavidin / Q000032:analysis* / Q000737:chemistry; D014173:Transistors, Electronic
chemical_list: D054370:Chemokine CXCL9; D019809:Streptavidin