Nanostructured wearable electrochemical and biosensor towards healthcare management: a review

Abstract

In recent years, there has been a rapid increase in demand for wearable sensors, particularly these tracking the surroundings, fitness, and health of people. Thus, selective detection in human body fluid is a demand for a smart lifestyle by quick monitoring of electrolytes, drugs, toxins, metabolites and biomolecules, proteins, and the immune system. In this review, these parameters along with the main features of the latest and mostly cited research work on nanostructured wearable electrochemical and biosensors are surveyed. This study aims to help researchers and engineers choose the most suitable selective and sensitive sensor. Wearable sensors have broad and effective sensing platforms, such as contact lenses, Google Glass, skin-patch, mouth gourds, smartwatches, underwear, wristbands, and others. For increasing sensor reliability, additional advancements in electrochemical and biosensor precision, stability in uncontrolled environments, and reproducible sample conveyance are necessary. In addition, the optimistic future of wearable electrochemical sensors in fields, such as remote and customized healthcare and well-being is discussed. Overall, wearable electrochemical and biosensing technologies hold great promise for improving personal healthcare and monitoring performance with the potential to have a significant impact on daily lives. These technologies enable real-time body sensing and the communication of comprehensive physiological information.

Scheme 1. (A) Contact lens (https://xtalks.com/postech-researchers-develop-smart-contact-lenses-that-can-diagnose-and-treat-diabetes-2232/), (B) elastomeric stamp, (C) Google Glass (https://time.com/3669927/google-glass-explorer-program-ends/), (D) skin-patch (https://physicsworld.com/a/wearable-patch-could-predict-risk-of-stroke-and-heart-attacks/), (E) microfluidic device (https://innovationtoronto.org/index.php/2022/08/28/new-wearable-microfluidic-sensing-technology-can-provide-continuous-monitoring-for-many-health-conditions/), (F) mouthguard, (G) pulse-oximeter, (H) potentiostat, (I) smart watch, (J) temporary tattoo (https://www.wionews.com/science/tattoo-as-health-monitoring-device-south-korean-scientists-develop-unique-technology-502791), (K) underwear, and (L) wristband (https://www.medicaldesignandoutsourcing.com/wristband-detects-analyzes-real-time-changes-in-sweat-chemical-composition/). Figure is adopted from all reference sources with permission.

Fig. 1. Weaving carbon nanotube fiber to smart electrochemical fabric. Adopted from ref. with permission from American Chemical Society, Copyright© 2019.

Fig. 2. Stepwise potentiometric tattoo sensor fabrication. (A). Release the fabrication layer by the insulator, carbon, Ag/AgCl, and insulator. (B). Ion-selective and reference electrodes deposited onto the suitable area [adopted from ref. with permission from Wiley, Copyright© 2014].

Fig. 3. Schematic representation of levodopa (L-Dopa) detection, (A) hand-wearing mannequin microneedle sensor, (B) ISF levodopa monitoring, (C) wireless electroanalayser, (D) microneedle sensor platform for levodopa sensing using SWV and amperometry, (E) cross-sectional view of CP, tyrosinase and Nafion layer, (F) and, (G) optical image before and after CP packing of microneedles. Adopted from ref. with permission from American Chemical Society, Copyright© 2019.

Fig. 4. Transdermal alcohol sensor (A) iontophoretic tattoo electrode, (B) alcohol iontophoretic-sensing tattoo device, (C) diagram of iontophoresis and amperometric detection of alcohol, (D) diagram of iontophoresis system (left) and amperometric system (right). Adopted from ref. with permission from Elsevier, Copyright© 2018.

Fig. 5. Schematic illustrations of sweat gland structure, biomarker secretion, and wearable biosensor for uric acid detection in sweat. Adopted from ref. with permission from Elsevier, Copyright© 2021.

Fig. 6. Wearable sweat analysis patch based on SilkNCT. (A) and (B) Schematic illustration of wearable sweat analysis patch mounted on human skin (A) and the multiplex electrochemical sensor array integrated into the patch (B). (C) Photograph of the wearable sweat analysis patch. Adopted from ref. with permission from the American Association for the Advancement of Science (AAAS), Copyright© 2019.

Fig. 7. Microfluidic device design and operation. The soft epidermal microchip device conforms to the skin and routes the sampled sweat toward the electrochemical detector. (A) Schematic representation of layered microfluidic device configuration on skin composed of (i) top PDMS layer with incorporated sensor electrodes, (ii) PDMS microfluidic device, and (iii) adhesive layer on the skin. (B) Schematic representation of microfluidic device sweat collection and operation on the skin in top-down and cross-sectional views. (C) Photograph of microfluidic device integrated with wireless conformal electronics on skin with lithography-based gold current collectors and screen-printed silver–silver chloride (RE) and Prussian blue (WE and CE). Adopted from ref. with permission from American Chemical Society, Copyright© 2019.

Fig. 8. Wearable contact lens packaging, (A) smart contact lens integrated with three-dimensional interconnects, the sensor on the rigid island. A capacitor and resistor were interconnected for resonance frequency and reference resistance. (B) Fabricated smart contact lens, (C) optical transmittance and haziness of hybrid material, (D) after and before radiation characteristics of the stretchable antenna, (E) relative resonance frequency in PBS and artificial tears up to 192 hours (inset: radiation characteristics of antenna in artificial tears for 12 and 192 hours). Adopted from ref. with permission from Elsevier, Copyright© 2019.

Fig. 9. Fabrication of Human Interferon-gamma (IFN-γ) immunosensor for the detection in serum samples. The figure is adopted from with permission from The Royal Society of Chemistry, Copyright© 2020.