Utilizing RF Resonators to Monitor States of Hydration on the Skin's Surface in Real-Time.
Dehydration is a physiological side effect of exertion that affects everyone to some
degree and can be remedied easily. However, when the rate of dehydration is not
monitored appropriately, serious physical consequences can occur. Studies have shown
that sweat loss amounting to 2-3% of body weight leads to impaired thermoregulation and
increased muscle fatigue, while 5-6% can lead t... read moreo heat stroke and even coma. The
development of a real-time biosensor to monitor the conditions on the skin's surface and
relay that information to a qualified physician or trainer is tantamount to effectively
monitoring dehydration. As the details of this work outline, efforts are under way to
combine an RF resonator and a variety of biocompatible materials to realize the
application of a real-time hydration sensor. By exploiting and measuring the electrical
characteristics of the RF resonator, changes in the surrounding environment will alter
the resonator's response. These include changes in both the dielectric and conductivity
of the material in contact with the resonator. This is particularly useful for
monitoring the hydration level on the surface of the skin, as both the amount of sweat
and salt content of sweat vary as dehydration occurs. Silkworm silk is explored as an
absorbing layer, as it can be purified and manipulated to form a porous sponge-like form
factor. Alternately, cellulose materials currently used in sweat patches can be utilized
in the overall sweat patch design. Whether made of cellulose or silk, this absorbing
layer is incorporated with the RF resonator to wick sweat at the skin's surface and
bring it in contact with the interrogating resonator. Initial test show that changes in
physiologically relevant sweat concentrations can be detected by the RF resonator,
showing great promise for this biocompatible real-time, non-invasive hydration
Thesis (M.S.)--Tufts University, 2012.
Submitted to the Dept. of Biomedical Engineering.
Advisor: Fiorenzo Omenetto.
Committee: David Kaplan, and Hu Tao.
Keywords: Biomedical engineering, and Electrical engineering.read less