Tattoo-based potentiometric ion-selective sensors for epidermal pH monitoring

• Published in: Analyst (London) Vol. 138; no. 1; pp. 123 - 128
• Main Authors: Bandodkar, Amay J, Hung, Vinci W. S, Jia, Wenzhao, Valdés-Ramírez, Gabriela, Windmiller, Joshua R, Martinez, Alexandra G, Ramírez, Julian, Chan, Garrett, Kerman, Kagan, Wang, Joseph
• Format: Journal Article
• Language: English
• Published: England 01.01.2013
• Subjects: Adult; Electrodes; Epidermis - chemistry; Human behavior; Humans; Hydrogen-Ion Concentration; Male; Monitoring; Potentiometry - instrumentation; Sensors; Surface chemistry; Tattooing; Tattoos; Wearable
• ISSN: 0003-2654; 1364-5528
• DOI: 10.1039/c2an36422k

This article presents the fabrication and characterization of novel tattoo-based solid-contact ion-selective electrodes (ISEs) for non-invasive potentiometric monitoring of epidermal pH levels. The new fabrication approach combines commercially available temporary transfer tattoo paper with conventional screen printing and solid-contact polymer ISE methodologies. The resulting tattoo-based potentiometric sensors exhibit rapid and sensitive response to a wide range of pH changes with no carry-over effects. Furthermore, the tattoo ISE sensors endure repetitive mechanical deformation, which is a key requirement of wearable and epidermal sensors. The flexible and conformal nature of the tattoo sensors enable them to be mounted on nearly any exposed skin surface for real-time pH monitoring of the human perspiration, as illustrated from the response during a strenuous physical activity. The resulting tattoo-based ISE sensors offer considerable promise as wearable potentiometric sensors suitable for diverse applications. Temporary transfer tattoo-based all-solid contact potentiometric sensors are fabricated by combining screen printing, temporary tattoo and conducting polymer technology and evaluated for real-time epidermal pH monitoring.