Electrochemiluminescent (ECL) biosensor for Burkholderia pseudomallei based on cobalt-doped MOF decorated with gold nanoparticles and N-(4-aminobutyl)-N-(ethylisoluminol).

A multifunctional catalytic nanomaterial (Co-MOF@AuNP@ABEI) composed of cobalt-doped metal-organic frameworks (Co-MOF), gold nanoparticles (AuNP), and N-(4-aminobutyl)-N-(ethylisoluminol) (ABEI) is reported. Co-MOF@AuNP@ABEI exhibits high synergistic and zero-distance catalytic properties, which are beneficial to the improvement of the detection sensitivity of an electrochemiluminescent (ECL) biosensor. After coupling with the ECL system and 3D magnetic walking nanomachine amplification strategy, the Co-MOF@AuNP@ABEI can achieve an ultrasensitive ECL assay of Burkholderia pseudomallei with the limit of detection (LOD) of 60.3 aM, which is 2 and 4 orders of magnitude lower than individual ECL system without the nanomachine (4.97 fM) and individual walking nanomachine (340 fM), and superior to the pathogenic bacteria analyses in the previous report. Moreover, the LOD of the proposed ECL detection system for the determination of B. pseudomallei in serum sample was as low as 9.0 CFU mL. The relative standard deviations (RSD) of ECL intensity for the detection of five B. pseudomallei-spiked serum samples were 4.02%, 0.84%, 0.84%, 1.55%, and 0.21%, respectively. The recoveries of the ECL biosensor for the detection of B. pseudomallei DNA-spiked serum samples were 93.63 ~ 107.83%. Therefore, this work demonstrated that the developed multifunctional catalytic nanomaterial with synergistic and zero-distance catalytic properties can be used as excellent ECL signal reporter to improve the detection sensitivity of ECL biosensor.