All-covalent reduced graphene oxide FET immunosensor optimized by interface engineering

Immunosensors with antigen-antibody specific binding exhibit broad application prospects due to their excellent specificity and label-free high-sensitivity detection characteristics. However, it's still a challenge to construct a stable biosensing interface to covalently attach bio-probe, avoiding interference from other substances. Therefore, an all-covalent reduced graphene oxide-based field-effect transistor (RGO-FET) immunosensor was successfully developed, where the reduced graphene oxide active layer was interface modified by cross-linking agent 1-pyrenebutanoicacid, 2,5-dioxo-1-pyrrolidinylester after optimization of its concentration. Then, α-fetoprotein antibody was covalently bonded to construct a high-performance biosensing platform for tumor marker α-fetoprotein detection. In addition, the prepared RGO-FET based immunosensor was blocked with ethanolamine blocking agent, which reduced the influence of non-specific adsorption during α-fetoprotein detection. Through interface engineering design, the immunosensor based on RGO-FET exhibits good sensing performance for α-fetoprotein bioassay and is expected to be applied for various biomarkers detection.