Flexible Scaffold Modulation of Spatial Structure and Function of Hierarchically Porous Nanoparticle@ZIF‐8 Composites to Enhance Field Deployable Disease Diagnostics

Abstract Catalytic nanoparticle@metal‐organic framework (MOF) composites have attracted significant interest in point‐of‐care testing (POCT) owing to their prominent catalytic activity. However, the trade‐off between high loading efficiency and high catalytic activity remains challenging because high concentrations of nanoparticles tend to cause the misjoining and collapse of the MOFs. Herein, a facile strategy is reported to encapsulate high concentrations of platinum (Pt) nanoparticles into zeolitic imidazolate framework‐8 (ZIF‐8) using polydopamine (PDA) as a support for Pt@ZIF‐8 and as a flexible scaffold for further immobilization of Pt nanoparticles. The resulting composite (Pt@ZIF‐8@PDA@Pt) exhibits ultrahigh Pt nanoparticle loading efficiency, exceptional catalytic activity, stability, and a bright colorimetric signal. Following integration with lateral flow immunoassay (LFIA), the detection limits for pre‐ and post‐catalysis detection of B‐type natriuretic peptide (NT‐proBNP) are 0.18 and 0.015 ng mL −1 , respectively, representing a 6‐fold and 70‐fold improvement compared to gold nanoparticle‐based LFIA. Moreover, Pt@ZIF‐8@PDA@Pt‐based LFIA achieves 100% diagnostic sensitivity for NT‐proBNP in a cohort of 184 clinical samples.