Wearable sensing technologies are becoming increasingly popular because of their vital contribution to human health, performance, personalized medicine and overall societal impact. The current generation of wearable sensor systems help to monitor health and/or provide clinically relevant data. Those that are commercially available commonly measure a real-time physiological response such as electrophysiological parameters including ECG (electrocardiography), EEG, and EMG another common example is optical sensors which can be used to measure heart rate.
Despite tremendous growth in wearable sensor platforms, there are a limited number of commercially available wearable devices capable of measuring and monitoring levels of biochemical markers present in the human body. One example is the continuous glucose monitoring system (CGM's), which are described as minimally-invasive as the sensing element (mini-needle) is inserted a couple of millimetres underneath the skin.
One of the major challenges for wearable devices is this ability to access areas containing biomarkers within biofluids in a non-clinical ambulatory context, and provide medically relevant measurements of the levels of the target analytes without the need for repeated manual measurement of those parameters which can be expensive and uncomfortable. Microneedles have been developed to penetrate up to 1 millimetre into the skin to interface with dermal interstitial fluid (skin tissue fluid) allowing non-invasive sensing or monitoring of various medically relevant analytes. Some potential applications include glucose monitoring, drug monitoring to assist with appropriate patient dosing as well as single use applications for cancer screening markers.
In a review paper recently published in the journal Sensing and Bio-Sensing Research, as part of the PhD thesis of Julia Madden, who works in the Life Sciences Interface Group at the Tyndall National Institute, the potential to integrate electrochemical sensors on to smart wearable microneedle patches was examined.
PhD researcher,
Life Sciences Interface Group,
Tyndall National Institute.
The paper identified a number of grand challenges that exist for biosensor integration with microneedle platforms, and explored previous research conducted on skin interstitial fluid to determine which of the significant biomarkers are present, how their concentrations relate to those in other biofluids, and how accessible these could be for monitoring using a minimally invasive wearable microneedle device.
The review article described and analysed the state of the art in terms of which biomarkers are present in the interstitial fluid within the skin tissue, as well as on the application of emerging non-invasive wearable platforms for sampling interstitial fluid. Emphasis was also placed on the microfabrication methods which enable integration of electrochemical biosensors with microneedle-based platforms.
The review concluded that electrochemical based microneedle devices open the possibility for minimally invasive biochemical detection within the interstitial fluid present in the upper layers of human skin, and that these technologies are likely to be part of next-generation wearable sensing systems.
Read more on the research paper here.
The review, which resulted from a collaboration between researchers based in Tyndall and Prof Michael Thompson in University of Toronto further complements current research within Tyndall in the area of smart microneedle diagnostic systems. The publication has emanated from research conducted with the financial support of Science Foundation Ireland under Grant number 12/RC/2289 which is co-funded under the European Regional Development Fund.