Engineering Perovskite Hydroxide as a Cold-Adapted Oxidase Mimic for Construction of the Robust Low-Temperature Adaptive Biosensors.

Traditional biological detection methods rely on signal amplification strategies such as enzymatic catalysis or nucleic acid amplification. However, their efficiency decreases in low-temperature environments, compromising their detection sensitivity. To break the loss of enzyme catalytic activity at low temperatures, research on cold-adaptive nanozymes has attracted much attention. Till now, only a few nanozymes have been reported to have cold-resistant catalytic properties. Here, a new type of cold-adapted nanozyme was constructed by engineering a perovskite hydroxide. The nanozyme not only boosted the oxidase-like catalytic activity by 2 orders of magnitude but also retained excellent catalytic performance at 0 °C. This enhanced activity may be attributed to the increase in manganese content, vacancy oxygen, and tetravalent manganese. Then, a robust low-temperature adaptive biosensor was established with a cold adaptive nanozyme. Notably, the detection of sulfide ion, ascorbic acid, alkaline phosphatase, and cellular glutathione by the cold-adapted probe was less affected by the temperature reduction, and the detection sensitivity of the probe for ALP at 0 °C is better than that of a commercial kit. Finally, the cold-adapted nanozyme was further used to construct a paper-based H2S gas colorimetric probe. This study develops a new cold adaptive nanozyme and broadens the application scenarios of the nanozymes.