Temperature-responsive nanozyme-mediated enrichment-confinement dual strategy breaks the non-responsive barrier for Triphenols: Highly responsive detection and differentiation of tea.

The predominant ortho-trihydroxyphenyl structure in tea polyphenols requires highly specific sensing materials for their detection. However, both natural enzymes and current polyphenol oxidase-like nanozymes exhibit inadequate responsiveness to this specific configuration. To overcome this limitation, a dual "enrichment-confinement" strategy was proposed, effectively addressing the suboptimal detection performance for triphenolic compounds. The efficacy of this strategy relies on a switchable hydrophilic-to-hydrophobic transition: substrate enrichment is driven by extended hydrophilic chains at low temperatures, whereas heating induces hydrophobic collapse and nanoscale contraction, thereby activating spatial confinement. This conformational change not only shortens the interactive distance between the nanozyme and the substrate but also mitigates undesirable substrate aggregation. Theoretical calculations further reveal that the interactions between the nanozyme and the thermosensitive polymer are primarily governed by van der Waals forces and hydrogen bonding, which notably preserve the nanozyme intrinsic catalytic activity. This method enables the precise differentiation of tea polyphenols with a detection limit as low as 100 nM. Notably, this technology extends beyond the detection of tea triphenols, broadening the application scope of polyphenol oxidase-like nanozymes and providing a novel paradigm for the sensitive detection of diverse triphenolic compounds.