Bifunctional S, N-Codoped carbon dots-based novel electrochemiluminescent bioassay for ultrasensitive detection of atrazine using activated mesoporous biocarbon as enzyme nanocarriers

A novel and ultrasensitive electrochemiluminescent (ECL) bioassay has been developed for the detection of atrazine (ATZ), whereby bifunctional S, N-codoped carbon dots (S, N-CDs) and activated mesoporous bicarbons (BCs) have been innovatively integrated to synergistically amplify the ECL signal. When endogenous dissolved O 2 is used as a coreactant, its sluggish reduction hinders the enhancement of ECL intensity of the luminophore, thus restricting its further application in bioanalysis . Here, bifunctional S, N-CDs severe as not only the ECL luminophore but the coreaction accelerator of dissolved O 2 to generate more intermediates to boost the coreaction without using any other coreactant and coreaction accelerator. The as-formed nanoarchitectures of BCs possess enlarged surface area as the nanocarriers . They could provide adequate active sites for immobilization of tyrosinase (Tyr), which greatly prompts the ECL bioassay applications. Such a smart integration of bifunctional S, N-CDs, activated mesoporous BCs and the enzyme inhibition reaction achieves a unique and attractive high-performance signal-on ECL bioassay, realizing ultrasensitive detection of ATZ. Under the optimal condition, this bioassay exhibits two linear ranges, from 0.0001 to 0.01 μg L −1 and 0.01–20 μg L −1 with a detection limit of 0.08 ng L −1  at signal to noise ratio of 3. The as-fabricated assay is sensitive and economical, opening a new way for the enhancement of ECL signal output and a versatile strategy for ultrasensitive ECL bioanalysis.