Enzymatic biofuel cells-based self-powered electrochemical biosensor for detection of 17β-estradiol based on dual-enzyme cascade amplification and bioconjugate

Abstract

Self-powered electrochemical biosensors (SPEB) based on enzymatic biofuel cells (EBFC) have garnered significant attention due to their distinctive characteristic of not necessitating the source of external power supply. This study developed a novel EBFC-based SPEB by incorporating dual-enzyme cascade amplification and bioconjugate for extremely precise detection of 17β-estradiol (E2). The carbon nanocages/gold nanoparticles composite was employed as substrate to immobilize bilirubin oxidase (BOD) and complementary ssDNA (csDNA) to form bioconjugate. The carbon nanotubes/gold nanoparticles composite was used in the EBFC device as the electrode material, through which glucose oxidase (GOD) and E2 aptamer were wired to form the bioanode and biocathode, respectively. The biocathode further linked with bioconjugate via a hybridization reaction between E2 aptamer and csDNA. The bioconjugate integrates the recognition and signal probes for homogeneous electrochemical assay of targets, which released from biocathode once the target E2 was recognized and hindered the transfer of electrons produced by GOD on bioanode. Thus, the open-circuit voltage (EOCV) of the EBFC-based SPEB dramatically decreased, exhibiting exceptional sensitivity for the detection of E2 over a concentration range from 10 pg mL−1 to 20 ng mL−1, with a detection limit of 3.3 pg mL−1 (S/N = 3). Furthermore, the prepared EBFC-based SPEB showed significant potential for implementation as a viable prototype for a mobile and an on-site bioassay system in food and environmental safety applications.