A Metal Organic Framework Derived Nano Porous Carbon (NPC)-MWCNT Heterostructured Nanocomposite-Based Electrochemical Sensing Patch for Sweat Ca ion and pH Monitoring

This paper describes a core-shell structured Metal Organic Framework-derived nano porous carbon (NPC)/MWCNT nanocomposite-based electrochemical patch with a sweat-collecting fluidic channel for Ca
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ion and pH sensing applications. Due to the inherent high ion-to-electron transduction property of multi-walled carbon nanotube (MWCNT), high surface area, and graphitic structure of NPC, the fabricated Ca
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ion and pH sensors exhibited excellent stable performance by forming a high double layer capacitance at the interface of the ion-selective membrane and the solid contact composed of NPC/MWCNT nanocomposite. The fabricated patch sensor showed 34.4 mV/decade sensitivity toward the Ca
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concentration range (0.25–10 mM) and a sensitivity of -71 mV/pH for the pH range (3–9). Our study paves the way to connect a wide range of carbon-based materials to an infinite number of metal-organic frameworks as a transduction material for sensing applications.