Vertically aligned gold nanowires as stretchable and wearable epidermal ion-selective electrode for noninvasive multiplexed sweat analysis

Qingfeng Zhai, Lim Wei Yap, Ren Wang, Shu Gong, Zhirui Guo, Yiyi Liu, Quanxia Lyu, Joseph Wang, George P. Simon, Wenlong Cheng

Research output: Contribution to journalArticleResearchpeer-review

6 Citations (Scopus)

Abstract

The noninvasive continuous analysis of human sweat is of great significance for improved healthcare diagnostics and treatment in the future, for which a wearable potentiometry-based ion-selective electrode (ISE) has attracted increasing attention, particularly involving ion detection. Note that traditional solid-state ISE electrodes are rigid ion-to-electron transducers that are not conformal to soft human skin and cannot function under stretched states. Here, we demonstrated that vertically aligned mushroom-like gold nanowires (v-AuNW) could serve as stretchable and wearable ion-to-electron transducers for multiplexed, in situ potentiometric analysis of pH, Na+, and K+ in sweat. By modifying v-AuNW electrodes with polyaniline, Na ionophore X, and a valinomycin-based selective membrane, we could specifically detect pH, Na+, and K+, respectively, with high selectivity, reproducibility, and stability. Importantly, the electrochemical performance could be maintained even under 30% strain and during stretch-release cycles without the need of extrinsic structural design. Furthermore, our stretchable v-AuNW ISEs could be seamlessly integrated with a flexible printed circuit board, enabling wireless on-body detection of pH, Na+, and K+ with fast response and negligible cross-talk, indicating considerable promise for noninvasive wearable sweat analysis.

Original languageEnglish
Pages (from-to)4647-4655
Number of pages9
JournalAnalytical Chemistry
Volume92
Issue number6
DOIs
Publication statusPublished - 17 Mar 2020

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