Colorimetric biosensing has become a popular sensing method for the portable detection of a variety of biomarkers. Artificial biocatalysts can replace traditional natural enzymes in the fields of enzymatic colorimetric biodetection; however, the exploration of new biocatalysts with efficient, stable, and specific biosensing reactions has remained challenging so far. Here, to enhance the active sites and overcome the sluggish kinetics of metal sulfides, the creation of an amorphous RuS2 (a-RuS2 ) biocatalytic system is reported, which can dramatically boost the peroxidase-mimetic activity of RuS2 for the enzymatic detection of diverse biomolecules. Due to the existence of abundant accessible active sites and mildly surface oxidation, the a-RuS2 biocatalyst displays a twofold Vmax value and much higher reaction kinetics/turnover number (1.63 × 10-2 s-1 ) compared to that of the crystallized RuS2 . Noticeably, the a-RuS2 -based biosensor shows an extremely low detection limit of H2 O2 (3.25 × 10-6 m), l-cysteine (3.39 × 10-6 m), and glucose (9.84 × 10-6 m), respectively, thus showing superior detection sensitivity to many currently reported peroxidase-mimetic nanomaterials. This work offers a new path to create highly sensitive and specific colorimetric biosensors in detecting biomolecules and also provides valuable insights for engineering robust enzyme-like biocatalysts via amorphization-modulated design.
Keywords: amorphous structures; colorimetric detection; enzymatic nanomaterials; metal sulfides; peroxidase-mimics.
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