Aptasensor for Mycobacterium tuberculosis antigen MPT64 detection using anthraquinone derivative confined in ordered mesoporous carbon as a new redox nanoprobe.

• AQCA/CMK-3 nanohybrid was employed as a new redox nanoprobe for the first time. • Urchin-like Ce-MOFs were used as favorable platform to accelerate electron transfer. • Sandwich-type aptasensor was constructed with excellent sensitivity and specificity. • This approach was utilized to detect MPT64 in human serum with satisfactory results. Rapid and sensitive tuberculosis (TB) diagnoses remain big challenges to current detection tools. In this work, a sensitive electrochemical aptasensor was constructed for the determination of Mycobacterium tuberculosis antigen MPT64 using a new redox nanoprobe. We found that anthraquinone derivative, anthraquinone-2-carboxylic acid (AQCA), a redox mediator, could be confined in ordered mesoporous carbon material of CMK-3. Due to the large loading amount of AQCA, as well as the confined space and electron transfer promotion effect of CMK-3, the obtained AQCA/CMK-3 nanohybrid with mass ratio of 2:1 showed excellent electroactivity and was employed as a new redox nanoprobe for signal amplification for the first time. Additionally, urchin-like Ce-MOFs were used to load a large amount of deposited gold nanocrystals (dep-Au), leading to dense immobilization of capture probe. The proposed electrochemical aptasensor for MPT64 detection showed a good linear relationship in the range from 100 fg/mL to 10 ng/mL with a low detection limit of 67.6 fg/mL. Besides, the aptasensor was utilized to detect MTP64 in human serum samples for TB diagnosis and presented satisfactory results. [ABSTRACT FROM AUTHOR]