3D Hierarchical Nanoarchitecture AuNPs/MXene@PAMAM based Biosensor for cTnT Detection in Human Serum *

2D MXene-Ti 3 C 2 T χ has demonstrated promising application prospect in various fields, however, failing to function properly in biosensor setup due to restacking and anodic oxidation problem. Herein, we reported a synthesis study of covalently grafting MXene by first-generation poly(amidoamine) (PAMAM) dendrimers with AuNPs self-adsorption (AuNPs/MXene@PAMAM) to consider it as a potential functional nanoplatform for electrochemical sensing. In this hybrid system, MXene provided a highly conductive substrate and specific 2D architecture; PAMAM not only acted as an efficient stabilizer simultaneously suppressing serious restacking and oxidation of MXene under anodic potential and consequently improving the electrochemical performance but also as a signal amplifier offering large specific surface areas and massive amino terminals to adsorb Au nanoparticles (AuNPs) for the final formation of 3D hierarchical nanoarchitecture. This functional platform containing abundant active sites was allowed to directly and covalently immobilize thiol-linked anti-cardiac troponin T (cTnT) antibody as the biorecognition element to fabricate the cTnT immunosensor. Preliminary results indicated that this immunosensor was validated with a fast and sensitive response toward cTnT in presence of [Fe(CN) 6 ]3-/4- redox marker and displayed a wide detection range from 0.1 to 1000 ng/mL and a limit of detection (LOD) of 0.069 ng/mL. This highperformance MXene-based nanobiosensing platform has the potential applicability in bioanalysis of cTnT or other biomarkers and opens a new pathway for expanding its application in the electrochemical biosensing field.