One-step self-assembly of multilayer graphene oxide via streamlined click reactions for sensitive colorimetric assays

Hemin-loaded graphene oxide with excellent peroxidase-like activity shows great potential for biosensing applications. However, the detection sensitivity of biosensors based on such catalytic methods is limited by the lack of a signal amplification technique. In this work, we developed a simple and rapid signal amplification method based on streamlined click reactions enabling one-step assembly of multilayer graphene oxide nanosheets on magnetic beads to immobilize large amounts of hemin serving as active catalysts, which allowed for the highly sensitive detection of various biological targets, including copper ions, DNA sequences and proteins. With this method, we achieved detection limits down to 13.74 nM, 4.89 pM and 7.77 pg/mL for Cu²⁺, Ebola virus DNA sequences, and carcinoembryonic antigen, respectively. The designed platform holds great promise in the self-assembly of graphene-based nanozymes and sensitive colorimetric biosensing in a wider range of applications.