Cheon Lab

[Abstract]

Despite various approaches to immunoassay and chromatography for monitoring cortisol concentrations, conventional
methods require bulky external equipment, which limits their use as mobile health care systems. Here,
we describe a human pilot trial of a soft, smart contact lens for real-time detection of the cortisol concentration in
tears using a smartphone. A cortisol sensor formed using a graphene field-effect transistor can measure cortisol
concentration with a detection limit of 10 pg/ml, which is low enough to detect the cortisol concentration in human
tears. In addition, this soft contact lens only requires the integration of this cortisol sensor with transparent
antennas and wireless communication circuits to make a smartphone the only device needed to operate the lens
remotely without obstructing the wearer’s view. Furthermore, in vivo tests using live rabbits and the human pilot
experiment confirmed the good biocompatibility and reliability of this lens as a noninvasive, mobile health care
solution.