A novel Cu-metal-organic framework with two-dimensional layered topology for electrochemical detection using flexible sensors

We present a novel Cu-metal-organic framework (MOF) with two-dimensional layered topology and techniques to integrate it with flexible sensors for electrochemical detection. The unique Cu-MOF is formed by coordinating Cu2+ ions with carboxylic oxygen groups, resulting in layered structures interlayerly connected by hydrogen bonds. The resulting flexible sensors exhibit capability in detecting ascorbic acid (AA), hydrogen peroxide (H2O2) and L-Histidine (L-His) with detection limits of 2.94, 4.1 and 5.3 μM, respectively. The linear ranges of the sensors compare favorably with other sensors based on rigid platforms that offer similar sensitivity. According to the result of cytotoxicity study, the MOFs-modified flexible sensors exhibit good biocompatibility to cells, suggesting potential use in in vivo chemical detection. The results presented here demonstrate applications of MOFs in facilitating highly stable electrochemical detection in flexible electronics, and provide fundamental knowledge about structure-dependent electrochemical properties of MOFs and changing behaviors of flexible MOFs membranes under external strain. More MOFs-based flexible sensors may be developed to explore different properties of MOFs by varying their compositions and structures for healthcare and clinic applications.