In this study, we developed the Pt-Ni hydrogels composed of the alloyed nanowires and Ni(OH)₂ nanosheets, which had been demonstrated excellent peroxidase-like and electrocatalytic properties toward hydrogen peroxide (H₂O₂). On the basis of these characteristics, a portable dual-mode H₂O₂ sensor was successfully constructed (Figure 1).

    The microstructures of the Pt-Ni hydrogels have been deeply investigated in our previous work (Small, 19, 2206868). In this article, we mainly explored their catalytic performances toward H₂O₂, especially their peroxidase-like activities. As shown in Figure 2, we engineered the component of the Pt-Ni hydrogels to find out the optimal ratio of Pt and Ni elements. Finally, the PtNi₃ hydrogel was select out due to its highest affinity and catalytic activity.

    The outstanding electrocatalytic characteristics of the PtNi₃ hydrogel toward H₂O₂ was also demonstrated in this work. Finally, we utilized the PtNi₃ dual-structure hydrogel to construct a portable biosensor which can support both the visual and electrochemical testing modes (Figure 3). Considering the importance of H₂O₂ analysis in the living cells, we used these two modes of portable sensor to measure the H₂O₂ content in the CHAPS-stimulated HeLa cells. The testing results were verified by the standard instruments, demonstrating the reliability of the developed sensing platform.

You can read more about our work in the article in Microsystem & Nanoengineering following the link: https://www.nature.com/articles/s41378-023-00623-y