title: A Wearable Electrochemical Platform for Noninvasive Simultaneous Monitoring of Ca(2+) and pH.
abstract: Homeostasis of ionized calcium in biofluids is critical for human biological functions and organ systems. Measurement of ionized calcium for clinical applications is not easily accessible due to its strict procedures and dependence on pH. pH balance in body fluids greatly affects metabolic reactions and biological transport systems. Here, we demonstrate a wearable electrochemical device for continuous monitoring of ionized calcium and pH of body fluids using a disposable and flexible array of Ca(2+) and pH sensors that interfaces with a flexible printed circuit board. This platform enables real-time quantitative analysis of these sensing elements in body fluids such as sweat, urine, and tears. Accuracy of Ca(2+) concentration and pH measured by the wearable sensors is validated through inductively coupled plasma-mass spectrometry technique and a commercial pH meter, respectively. Our results show that the wearable sensors have high repeatability and selectivity to the target ions. Real-time on-body assessment of sweat is also performed, and our results indicate that calcium concentration increases with decreasing pH. This platform can be used in noninvasive continuous analysis of ionized calcium and pH in body fluids for disease diagnosis such as primary hyperparathyroidism and kidney stones.
authors.affiliation: Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: Hnin Yin Yin
authors.initials: HY
authors.lastname: Nyein
authors.affiliation: Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: Wei
authors.initials: W
authors.lastname: Gao
authors.forename: Ziba
authors.initials: Z
authors.lastname: Shahpar
authors.affiliation: Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.|Stanford Genome Technology Center, Stanford School of Medicine , Palo Alto, California 94304, United States.
authors.forename: Sam
authors.initials: S
authors.lastname: Emaminejad
authors.affiliation: Stanford Genome Technology Center, Stanford School of Medicine , Palo Alto, California 94304, United States.
authors.forename: Samyuktha
authors.initials: S
authors.lastname: Challa
authors.affiliation: Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: Kevin
authors.initials: K
authors.lastname: Chen
authors.forename: Hossain M
authors.initials: HM
authors.lastname: Fahad
authors.affiliation: Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: Li-Chia
authors.initials: LC
authors.lastname: Tai
authors.affiliation: Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Ota
authors.affiliation: Stanford Genome Technology Center, Stanford School of Medicine , Palo Alto, California 94304, United States.
authors.forename: Ronald W
authors.initials: RW
authors.lastname: Davis
authors.affiliation: Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: Ali
authors.initials: A
authors.lastname: Javey
mesh_terms: D002118:Calcium / Q000032:analysis*; D004573:Electrolytes; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007477:Ions; D013542:Sweat / Q000737:chemistry*; D000076251:Wearable Electronic Devices
chemical_list: D004573:Electrolytes; D007477:Ions; D002118:Calcium
keywords: flexible electronics; in situ analysis; multiplexed sensing; system integration; wearable biosensors