Research ArticleBiosensors

A soft, wearable microfluidic device for the capture, storage, and colorimetric sensing of sweat

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Science Translational Medicine  23 Nov 2016:
Vol. 8, Issue 366, pp. 366ra165
DOI: 10.1126/scitranslmed.aaf2593

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  • Sweat vs blood lactate: comment on “A soft, wearable microfluidic device for the capture, storage, and colorimetric sensing of sweat”
    • Elena V. Karpova, junior research scientist, Chemistry faculty of M.V. Lomonosov Moscow State University, 119991, Moscow, Russia
    • Other Contributors:
      • Aleksey I. Laptev, research scientist, Russian State University of Physical Education, Sports, Youth and Tourism, Moscow, Russia
      • Egor A. Andreev, research scientist, Chemistry faculty of M.V. Lomonosov Moscow State University, 119991, Moscow, Russia
      • Elena E. Karyakina, senior research scientist, Chemistry faculty of M.V. Lomonosov Moscow State University, 119991, Moscow, Russia
      • Arkady A. Karyakin, professor, Chemistry faculty of M.V. Lomonosov Moscow State University, 119991, Moscow, Russia

    The recently published article (1) reports on monitoring of human perspiration, determining the only L-lactate among known metabolites. The usefulness of this (1) and similar devices (2) is, however, doubtful according to the generally accepted point of view (3), that it is impossible to use sweat lactate for non-invasive diagnostics. This conclusion is based on the reports that there is no relationship (4) or even negative correlation between lactate levels in blood and in sweat (5-7).
    We note that known contradictory data on relationship between sweat and blood lactate levels can be systematized by distinguishing sweat samples from the working and latent muscle areas.
    In order to cause the blood lactate increase we’ve chosen incremental exhaustive cycle ergometer exercise. Simultaneously sweat collected from the working muscle area (thigh) displays sharp increase in lactate content. On the contrary, no increase of lactate concentration in course of the exercise has been observed in arm (latent muscle area) sweat.
    The contradictory behavior of sweat lactate levels can be explained as follows. Sweat lactate (similarly to blood lactate) was reported to be a product of muscle metabolism (8, 9). Hence, hypoxia of the working muscle causing an increase of tissue lactate (9) should cause a rise of lactate content in sweat samples collected from the corresponding body region. Concerning latent muscle, on the contrary, it is expected to be over-oxygenated due to...

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    Competing Interests: None declared.

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