A self-powered electrochemical aptasensor for detection of 17β-estradiol based on carbon nanocages/gold nanoparticles and DNA bioconjugate mediated biofuel cells

17β-Estradiol (E2) is an important endogenous estrogen, which disturbs the endocrine system and poses a threat to human health because of its accumulation in human body. Herein, a biofuel cells (BFCs)-based self-powered electrochemical aptasensor was developed for E2 detection. Porous carbon nanocages/gold nanoparticles composite modified indium tin oxide (CNCs/AuNPs/ITO) and glucose oxidase modified CNCs/AuNPs/ITO were used as biocathode and bioanode of BFCs, respectively. [Fe(CN)6]3− was selected as electroactive probe, which entrapped in the pores of positively charged magnetic Fe3O4 nanoparticles (PMNPs) and then capped with negatively charged E2 aptamer to form a DNA bioconjugate. The presence of the target E2 triggered the entrapped [Fe(CN)6]3− probe release due to the removal of the aptamer via specific recognition, which resulted in the transfer of electrons produced by glucose oxidation at the bioanode to the biocathode and produced a high open-circuit voltage (EOCV). Consequently, a “signal-on” homogeneous self-powered aptasensor for E2 assay was realized. Promisingly, the BFCs-based self-powered aptasensor has particularly high sensitivity for E2 detection in the concentration range of 0.5 pg mL−1 − 15 ng mL−1 with a detection limit of 0.16 pg mL−1 (S/N = 3). Therefore, the proposed BFCs-based self-powered electrochemical aptasensor has a great promise to be applied as a successful prototype of portable and on-site bioassay in the field of environment monitoring and food safety.