Hollow Microfibers of Elastomeric Nanocomposites for Fully Stretchable and Highly Sensitive Microfluidic Immunobiosensor Patch

The on-body immunodetection of biomarkers in sweat would significantly augment the potential of wearable body-interfaced biosensors for self-testing but has been limited due to the difficulty of integrating liquid handling and immunobiosensing devices in a wearable platform. Herein, a stretchable microfluidic immunobiosensor (SMIB) patch with hollow microfibers of elastomeric nanocomposites for the highly sensitive on-body biosensing of neuropeptide Y (NPY), a stress biomarker, in human sweat is reported. The SMIB patch is composed of a stretchable liquid handling device and an electrochemical impedimetric immunobiosensor made of hollow and conductive microfibers of reduced graphene oxide (rGO) and rGO-Ag nanowires in polyurethane matrix, respectively. The patch possesses a low limit of detection of 50 fm, a large dynamic range (50 fm-1 nm), good linearity, no labeling or reagent requirements, and facile formation in a patch form factor. By combining handling of the biofluid and delivery of the washing solution by a simple finger-touch operation as well as the analytical capability of NPY with an extremely low concentration in human sweat, the SMIB patch is a promising approach toward wearable non-invasive immunodetection for self-testing.