Devices and related methods for epidermal characterization of biofluids

Skin-mounted or epidermal devices and methods for monitoring biofluids are disclosed. The devices comprise a functional substrate that is mechanically and/or thermally matched to skin to provide durable adhesion for long-term wear. The functional substrates allow for the microfluidic transport of biofluids from the skin to one or more sensors that measure and/or detect biological parameters, such as rate of biofluid production, biofluid volume, and biomarker concentration. Sensors within the devices may be mechanical, electrical or chemical, with colorimetric indicators being observable by the naked eye or with a portable electronic device (e.g., a smartphone). By monitoring changes in an individual's health state over time, the disclosed devices may provide early indications of abnormal conditions.