title: Epidermal tattoo potentiometric sodium sensors with wireless signal transduction for continuous non-invasive sweat monitoring.
abstract: This article describes the fabrication, characterization and application of an epidermal temporary-transfer tattoo-based potentiometric sensor, coupled with a miniaturized wearable wireless transceiver, for real-time monitoring of sodium in the human perspiration. Sodium excreted during perspiration is an excellent marker for electrolyte imbalance and provides valuable information regarding an individual's physical and mental wellbeing. The realization of the new skin-worn non-invasive tattoo-like sensing device has been realized by amalgamating several state-of-the-art thick film, laser printing, solid-state potentiometry, fluidics and wireless technologies. The resulting tattoo-based potentiometric sodium sensor displays a rapid near-Nernstian response with negligible carryover effects, and good resiliency against various mechanical deformations experienced by the human epidermis. On-body testing of the tattoo sensor coupled to a wireless transceiver during exercise activity demonstrated its ability to continuously monitor sweat sodium dynamics. The real-time sweat sodium concentration was transmitted wirelessly via a body-worn transceiver from the sodium tattoo sensor to a notebook while the subjects perspired on a stationary cycle. The favorable analytical performance along with the wearable nature of the wireless transceiver makes the new epidermal potentiometric sensing system attractive for continuous monitoring the sodium dynamics in human perspiration during diverse activities relevant to the healthcare, fitness, military, healthcare and skin-care domains.
authors: Department of NanoEngineering, University of California, San Diego La Jolla, CA 92093, USA.
authors: Amay J
authors: AJ
authors: Bandodkar
authors: Department of NanoEngineering, University of California, San Diego La Jolla, CA 92093, USA; Institute of Nano- and Biotechnologies, Aachen University of Applied Sciences, D-52428 Jülich, Germany.
authors: Denise
authors: D
authors: Molinnus
authors: Department of NanoEngineering, University of California, San Diego La Jolla, CA 92093, USA.
authors: Omar
authors: O
authors: Mirza
authors: Department of NanoEngineering, University of California, San Diego La Jolla, CA 92093, USA; Departamento de Química Analítica, Universitat Rovira i Virgili, 43007 Tarragona, Spain.
authors: Tomás
authors: T
authors: Guinovart
authors: Department of NanoEngineering, University of California, San Diego La Jolla, CA 92093, USA; Electrozyme LLC, Executive Square (Suite 485), San Diego, CA 92037, USA.
authors: Joshua R
authors: JR
authors: Windmiller
authors: Department of NanoEngineering, University of California, San Diego La Jolla, CA 92093, USA.
authors: Gabriela
authors: G
authors: Valdés-Ramírez
authors: Departamento de Química Analítica, Universitat Rovira i Virgili, 43007 Tarragona, Spain.
authors: Francisco J
authors: FJ
authors: Andrade
authors: Institute of Nano- and Biotechnologies, Aachen University of Applied Sciences, D-52428 Jülich, Germany.
authors: Michael J
authors: MJ
authors: Schöning
authors: Department of NanoEngineering, University of California, San Diego La Jolla, CA 92093, USA. Electronic address: josephwang@ucsd.edu.
authors: Joseph
authors: J
authors: Wang
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D004867:Equipment Design; D015444:Exercise; D006801:Humans; D017736:Ion-Selective Electrodes; D011199:Potentiometry / Q000295:instrumentation*; D012964:Sodium / Q000032:analysis / Q000378:metabolism*; D013542:Sweat / Q000737:chemistry / Q000378:metabolism*; D059015:Wireless Technology / Q000295:instrumentation*
chemical_list: D012964:Sodium
keywords: Epidermal electronics; Ion selective electrode; Screen printing; Sweat sodium; Wireless electronics