3D-assembled microneedle ion sensor-based wearable system for the transdermal monitoring of physiological ion fluctuations

Xinshuo Huang; Shantao Zheng; Baoming Liang; Mengyi He; Feifei Wu; Jingbo Yang; Hui-Jiuan Chen; Xi Xie

doi:10.1038/s41378-023-00497-0

3D-assembled microneedle ion sensor-based wearable system for the transdermal monitoring of physiological ion fluctuations

Microsyst Nanoeng. 2023 Mar 9:9:25. doi: 10.1038/s41378-023-00497-0. eCollection 2023.

Authors

Xinshuo Huang^#¹, Shantao Zheng^#¹, Baoming Liang¹, Mengyi He¹, Feifei Wu^{1

2}, Jingbo Yang³, Hui-Jiuan Chen¹, Xi Xie^{1

3}

Affiliations

¹ State Key Laboratory of Optoelectronic Materials and Technologies, School of Electronics and Information Technology; Guangdong Province Key Laboratory of Display Material and Technology, Sun Yat-Sen University, Guangzhou, China.
² Pazhou Lab, 510330 Guangzhou, China.
³ School of Biomedical Engineering, Sun Yat-Sen University, Guangzhou, China.

^# Contributed equally.

Abstract

Monitoring human health is of considerable significance in biomedicine. In particular, the ion concentrations in blood are important reference indicators related to many diseases. Microneedle array-based sensors have enabled promising breakthroughs in continuous health monitoring due to their minimally invasive nature. In this study, we developed a microneedle sensing-array integrated system to continuously detect subcutaneous ions to monitor human health status in real time based on a fabrication strategy for assembling planar microneedle sheets to form 3D microneedle arrays. The limitations of preparing 3D microneedle structures with multiple electrode channels were addressed by assembling planar microneedle sheets fabricated via laser micromachining; the challenges of modifying closely spaced microneedle tips into different functionalized types of electrodes were avoided. The microneedle sensing system was sufficiently sensitive for detecting real-time changes in Ca²⁺, K⁺, and Na⁺ concentrations, and it exhibited good detection performance. The in vivo results showed that the ion-sensing microneedle array successfully monitored the fluctuations in Ca²⁺, K⁺, and Na⁺ in the interstitial fluids of rats in real time. By using an integrated circuit design, we constructed the proposed microneedle sensor into a wearable integrated monitoring system. The integrated system could potentially provide information feedback for diseases related to physiological ion changes.

Keywords: Biosensors; Electrical and electronic engineering.