Stretchable pH sensing patch in a hybrid package

Abstract

Abstract-This work presents a novel stretchable pH sensing patch to detect the pH in body fluid which is one of the most important parameters in human health monitoring. The sensing patch is a hybrid package comprising of polyimide/gold-based stretchable interconnects and graphite composite-based flexible pH sensor. With the integration of stretchable interconnects, the patch is able to withstand external stretching up to 50% longer than its original length. Moreover, the electrical behavior of the patch does not degrade as studied by the real-time resistance investigation. In order to protect the connecting electrodes and wirings from direct contacting with solution under analysis, the sensing patch is encapsulated with elastic polymer with the active sensing area exposed. The fabricated patch reveals a high pH sensitivity of 36.2 µA/pH in the pH range between 5 and 9 which is validated through electrochemical and electroanalytical studies.

Printed flexible electrochemical pH sensors based on CuO nanorods

“…From our studies, we also observed that the reactions with pH solution also removed some of binder from the thick film and this means the most suitable use of proposed sensors will be in disposable systems. As a future work, we plan to study the performance of presented sensors in different cell culture medium and fabricate flexible/ stretchable pH sensors [28,29] that also have longer life time. For this purpose, we will also investigate more morphologies for CuO nanostructures and composites.…”

Wearable Printed Temperature Sensors: Short Review on Latest Advances for Biomedical Applications

“…The stretchable interconnects play significant role and are therefore considered as the main complementary component for developing wearable biosensing patches, as the deformable interconnects can absorb the stresses with negligible effects on the central sensing devices [49][50][51]. Therefore, a good combination of soft lightweight substrates, advanced functional nanomaterials making soft, thin sensing films and stretchable interconnects [52], and most importantly a robust fabrication technique for processing these low Tg (glass transition temperature) materials at ambient conditions, are desired for development of reliable wearable sensing patches [9,16,[53][54][55]. This paper highlights the latest developments made in geometric designs of the sensory cells, engineered nanomaterials (both inorganic and organic) and the fabrication methods particularly the solution-based printing technologies.…”

3D Printed Chromophoric Sensors

“…Indeed, Sylgard 184 is an ideal candidate for sensing applications because of its selective permeability to gases, optical transparency, chemical inertness, and ease of patterning via soft lithography, casting, and other techniques. As such, quite a bit of research has explored Sylgard 184 in active and passive sensors such as lab-on-a-chip devices for biosensing [20][21][22], mechanoresponsive devices, e.g., capacitive pressure (or tactile) sensors [23,24] and strain sensors [25,26], and environmental sensors that can detect changes in temperature [27,28], pH [29][30][31], relative humidity [32,33], and certain gas species [34,35]. In high-hazard occupations or areas where workers may be exposed to hazardous conditions, a device that produces an easy to see change can alert workers if a dangerous threat is immediately present.…”