Wearable Woven Electrochemical Biosensor Patch for Non‐invasive Diagnostics

Abstract

[a] 1IntroductionContinuous monitoring of health remotely using wearable sensors and body area networks [ 1] is receiving al ot of attention both in the academiaa sw ell as industry. The challenges in the area of networking are well studied and addressed. Wearable sensor technology,o nt he other hand, is enticingf or researchers,a si to ffers several challenges that need to be addressed. These include developing of wearable sensors which are flexible,d urable, reliable,b iocompatible and robust. Havings ensor output as an electrical signal is of great additional value as it aids in seamless integration of well-developed, alliede lectronics wherein transduction and wireless transmission could be carried out simultaneously,t hus enabling smart and remote healthcare.Need for minimally invasive and continuous real-time monitoring of physiologicala ctivities has ushered in aw ave of wearable sensors. Starting from the commercially successfulm inimally invasiveg lucose watch, aw ide range of wearable sensors were developedo ver the past decade for continuous monitoring of vital physiological parameters of clinical importance. At extileb ased device integrated with an electronic board for continuous remote monitoring of heartr ate and respirationr ate is demonstrated [2].T he field of wearable electrocardiogram (ECG) and electroencephalogram (EEG) electrodes has receivedawide attention with severalE CG bands and EEG headset systemsi ntegrated with wireless sensor networks successfully demonstrated [3][4][5][6][7][8].T he key challenge that is being addressed in the sensor side is the development of dry electrodes which are devoid of any gel [9][10][11][12].S pecifically in the case of ECG bands,i ti s nearly impossible to createa1 2l ead wearable electrode system which is comfortable owing to the locationso ft he electrodes.T he wearable sensors for ECG typically have three leads and it is essential to convert this three lead ECG signalt otraditional twelve lead ECG signal for the sakeo fd octors who are trained to diagnoset he patient conditionb asedo nt welve lead data. Al ot of signal processing algorithms and electronic boards are being developed for this purpose [13,14].Ac omprehensive review on wearable sensors for humanp hysiological monitoring is published and wellc ited in the literature [ 15].T he aforementioned sensors are traditionally non-invasive as they sense electrical signals and there is no analyte involved in the same.Sports and fitness regimesh ave seen as ubstantial increase in the deployment of non-invasive wearable sensors. Unlike ECG and EEG electrodes,t hese sensors predominantly detect analytesi ns weat. Aw earables ensor comprising humidity sensors embedded in textile was usedt om onitors weat rate [16].L ikewise,e lectrolytes in sweat that are of clinical importancew ere detected utilising multiwalledc arbon nanotubes embedded in nylon cloth [17].Electrochemical transduction is the ideal mechanism for developingw earable sensors for remotem onitoringa s the output of these devices beinge ...

The design, fabrication, and applications of flexible biosensing devices

“…g) Graphene nanomesh FETs GNM FET biosensor. 1pyrenebutanoic acid succinimidyl ester linker conjugated with the amino modified HER2- 5% changes after 90° bend for 500 cycles (Wang et al 2013) HBsAgbinding aptamer Amperometric FET hepatitis B surface antigen (HBsAg) 5-10% change until 200 bend cycles, improved until 500 bend cycles (Cho et al 2018) Pt NPs Amperometric Hydrogen Peroxide (H 2 O 2 ) 5% decrease sensor response after 100 bending cycles (Xiao et al) Textile/ Fabric Redox active molecules Amperometric Adrenaline, Ascorbic acid, dopamine 7.5mm bending radius showed no change in response (Gualandi et al) Lactate oxidase Amperometric Lactate <13% when bended, <11% when twisted (Modali et al 2016) None Amperometric NADH, ferrocyanide, H2O2 Minimal effect of stretching on NADH and ferrocyanide, improved signal from stretching for H2O2 (Yang et al 2010) Silk Glucose oxidase Amperometric H2O2 30-180° bend angle and 1000 bend times; 5-25% stretch (Liang et al 2014) Glucose oxidase Amperometric Ascorbic acid, dopamine, or glucose 30° or 150 cycles bend showed slight decrease in conductivity (Pal et al 2016b) Biosens Bioelectron. Author manuscript; available in PMC 2020 January 15.…”

Low Cost Layer by Layer Construction of CNT/Chitosan Flexible Paper‐based Electrodes: A Versatile Electrochemical Platform for Point of Care and Point of Need Testing

“…It is important to note that there are other studies were electrodes are called to be flexible as they are disposed over flexible layers but not any analysis of the electrode performance after mechanical deformation was done. In this study we determined for the first time the signal variation of paper electrodes (layer by layer construction) which exhibit minimal variation and showed to be similar to other electrodes constructed over nylon yarns , bandages and fabric .…”

Skin-interfaced systems for sweat collection and analytics

“…Such devices wrap onto the surface of the skin, where straps, bands, or biomedical adhesives hold them in place. At the skin interface, woven textiles ( 58 , 59 ) and thin hydrogels of porous chitosan, nafion, or polyvinyl chloride improve mechanical contact with the measurement electrodes to allow continuous monitoring of sweat analytes that emerge from pores in the skin ( 46 , 60 , 61 ). Although these materials establish coupling to the skin, they do not capture or store the sweat in a controlled fashion, nor do they allow for measurements of sweat rate or total sweat loss (local or global), because the device-skin interface does not form a water-tight seal and the sweat can readily permeate laterally through the hydrogels.…”