title: Tattoo-based potentiometric ion-selective sensors for epidermal pH monitoring.
abstract: 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.
authors.affiliation: Department of Nanoengineering, University of California San Diego, La Jolla, CA 92093-0448, USA.
authors.forename: Amay J
authors.initials: AJ
authors.lastname: Bandodkar
authors.forename: Vinci W S
authors.initials: VW
authors.lastname: Hung
authors.forename: Wenzhao
authors.initials: W
authors.lastname: Jia
authors.forename: Gabriela
authors.initials: G
authors.lastname: Valdés-Ramírez
authors.forename: Joshua R
authors.initials: JR
authors.lastname: Windmiller
authors.forename: Alexandra G
authors.initials: AG
authors.lastname: Martinez
authors.forename: Julian
authors.initials: J
authors.lastname: Ramírez
authors.forename: Garrett
authors.initials: G
authors.lastname: Chan
authors.forename: Kagan
authors.initials: K
authors.lastname: Kerman
authors.forename: Joseph
authors.initials: J
authors.lastname: Wang
mesh_terms: D000328:Adult; D004566:Electrodes; D004817:Epidermis / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D010209:Paper; D011199:Potentiometry / Q000295:instrumentation*; D013653:Tattooing