Key Laboratory of Groundwater Resources and Environment (Jilin University), Ministry of Education, College of New Energy and Environment, Jilin University, Changchun, 130021, PR China; Jilin Provincial Key Laboratory of Water Resources and Water Environment, College of New Energy and Environment, Jilin University, Changchun, 130021, PR China.
College of Food Science and Engineering, Jilin University, Changchun, 130062, PR China.
Anal Chim Acta. 2024 Nov 22;1330:343272. doi: 10.1016/j.aca.2024.343272. Epub 2024 Sep 28.
Time-Temperature Indicator (TTI) is an indicator device for real-time monitoring of the thermal history of the product. Due to the enzymatic reactions are affected by both time and temperature, enzymatic TTIs have been extensively studied and developed in recent years. However, enzymatic TTIs contain biologically active molecules (enzymes), which require high storage and use conditions. Most of them are designed to mix the system species together and irreversible reaction is undertaken. Nanozymes are the synthetic nanomaterials with similar biocatalytic functions as natural enzymes, which have extensive applications in analytical chemistry, biosensing, and environmental protection due to their facile synthesis, low cost, high stability and durability.
This work proposed to replace the natural laccase to laccase-like nanozyme, designed a novel and facile O-activated time-temperature indicator for the first time. Nanozyme had excellent thermal and storage stability, which could maintain fabulous catalytic activity in the wide temperature range of 10-80 °C and after a long-term storage. Based on the O was required to participate in the oxidation of laccase-catalyzed substrates, a squeeze-type O-activated TTI was designed by controlling O in the TTI system. The TTI was activated through extruding the O-coated airbag ruptured and producing an irreversible color reaction. Combined with a smartphone to extract the chromaticity for portable visual real-time monitoring. Five sets of TTIs were prepared based on the concentration of nanozyme, and the activation energies (Ea) ranging from 28.45 to 72.85 kJ mol, which were able to be fitted to products with Ea ranging from 3.45 to 97.8 kJ mol and the monitoring-time of less than 7 days.
Compared to the traditional enzymatic TTI, the TTIs designed based on nanozyme has the advantages of controlled activation, wider temperature monitor range and good stability. Providing a new approach to the development of real-time monitoring of smart devices.
时间-温度指示器（TTI）是一种用于实时监测产品热历史的指示器设备。由于酶反应同时受到时间和温度的影响，近年来人们广泛研究和开发了酶 TTI。然而，酶 TTI 包含生物活性分子（酶），这需要高的存储和使用条件。它们大多被设计为将系统物种混合在一起，并进行不可逆反应。纳米酶是具有类似天然酶生物催化功能的合成纳米材料，由于其易于合成、成本低、高稳定性和耐用性，在分析化学、生物传感和环境保护等领域得到了广泛的应用。
本工作提出用类漆酶纳米酶替代天然漆酶，首次设计了一种新颖、简便的 O 激活时间-温度指示剂。纳米酶具有出色的热稳定性和储存稳定性，能够在 10-80°C 的宽温度范围内保持极好的催化活性，并且在长期储存后仍能保持出色的催化活性。基于 O 需要参与漆酶催化底物的氧化，通过控制 TTI 系统中的 O，设计了一种挤压型 O 激活 TTI。通过挤压涂有 O 的气囊破裂并产生不可逆的颜色反应来激活 TTI。结合智能手机提取色度，实现便携式可视实时监测。基于纳米酶的浓度，制备了五组 TTI，其激活能（Ea）范围为 28.45-72.85kJ/mol，可以拟合 Ea 范围为 3.45-97.8kJ/mol 且监测时间小于 7 天的产品。
与传统的酶 TTI 相比，基于纳米酶设计的 TTI 具有可控激活、更宽的温度监测范围和良好的稳定性等优点。为开发实时监测的智能设备提供了新途径。
