MOF-Based Biomimetic Enzyme Microrobots for Efficient Detection of Total Antioxidant Capacity of Fruits and Vegetables

Green and efficient total antioxidant capacity (TAC) detection is significant for healthy diet and disease prevention. This work first proposed the concept of TAC colorimetric detection based on microrobots. A novel metal-organic framework (MOF)-based biomimetic enzyme microrobot (MIL-88A@Fe₃O₄) is developed that can efficiently and accurately detect the TAC of real fruits and vegetables. Unlike the previous colorimetric detection method to measure TAC which often requires the addition of toxic hydrogen peroxide (H₂O₂) or light, the microrobots strategy can realize efficient TAC detection without any additional chemicals or stimuli. This is attributed to the oxidase-like activity from MIL-88A, which is discovered and confirmed for the first time by experiments and theoretical calculations. In addition, the microrobots can significantly accelerate the color reaction, resulting in a significant improvement in the detection efficiency of TAC in the motion state owing to their self-stirring effect. More importantly, the results of the MOF-based biomimetic enzyme microrobots strategy for detecting TAC in real fruits and vegetables are comparable to those tested by commonly used quantitative detection kits, in addition to low cost, excellent stability, and anti-interference ability. This attractive MOF-based biomimetic enzyme microrobot holds great prospects for future applications in catalytic sensing and promoting a healthy diet.