Coupling WO3-x dots-encapsulated metal-organic frameworks and template-free branched polymerization for dual signal-amplified electrochemiluminescence biosensing

Developing accurate and sensitive DNA methyltransferase (MTase) analysis methods is essential for early clinical diagnosis and development of antimicrobial drug targets. In this work, by coupling WO3-x dotsencapsulated metal -organic frameworks (MOFs) as co -reactants and terminal deoxynucleotidyl transferase (TdT)-mediated template -free branched polymerization, a dual signal -amplified electrochemiluminescent (ECL) biosensor was constructed to detect DNA adenine methylation (Dam) MTase. The employment of WO3-x dots -encapsulated MOFs (i.e., NH2-UIO66@WO3-x) was not only beneficial for biomolecule conjugation because of the abundant amino groups but also led to a 7 -fold enhanced ECL response due to the increased loading of WO3-x. Moreover, TdT-mediated template -free branched polymerization promoted the capture of ECL emitters on the electrode surface, achieving 20 -fold enhanced signal amplification. The presented ECL biosensor demonstrated a low detection limit of 2.4 x 10-4 U/mL, and displayed high reliability for the detection of Dam MTase in both spiked human serum and E. coli cell samples, and for the screening of potential inhibitors. This study opens a new avenue for designing a dual signal amplificationbased ECL bioassay for Dam MTase and screening inhibitors in the fields of clinical diagnosis and drug development. (c) 2024 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.