Review—Flexible and Stretchable Electrochemical Sensing Systems: Materials, Energy Sources, and Integrations

Abstract

This review details the key progress made on flexible and stretchable electrochemical sensing systems, along with their relevant challenges and opportunities for the future. Stepping forward from traditional rigid electrodes, recent advancements in non-rigid electrochemical sensors offer new and exciting opportunities for various applications, such as biomedical, fitness, or environmental monitoring. The key factors in developing such devices are the materials and integrated systems needed to retain mechanical compliance while maintaining electrochemical functions. This requires a devotion to judiciously engineer both the underlying substrates and electrode materials. However, the realization of compliant electrochemical sensing devices still faces many obstacles. The requirements and potential strategies to enable flexible and stretchable electrodes are further discussed in this review. In addition to such sensing units, which mainly consist of electrodes and functionalized transducers, integrated systems also require miniaturized viable and mechanically compliant energy sources, as well as low-power electronics for controlling the device and wirelessly communicating with users. Such advancements, alongside other attractive functionalities such as self-healing and transparent properties, are also discussed. The innovative flexible and stretchable sensing systems will extend a variety of non‐invasive, minimally invasive, wearable, and implantable applications to patients. Examples of compliant sensing systems and relevant challenges are included alongside perspectives of this emerging technology.

Polycarbazole and Its Derivatives: Synthesis and Applications. A Review of the Last 10 Years

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Skin-Integrated Wearable Systems and Implantable Biosensors: A Comprehensive Review

“…Thus, for medical applications, it is mandatory to promote a replacement of silicon wafers by biocompatible, soft and flexible substrates, like biopolymer-based substrates, in order to alleviate that body-foreign issue and suppress fibrotic tissue encapsulation [56,60]. Commonly used polymeric substrates are polyethylene naphthalate, polyethylene terephthalateble and polyimide [63]. These polymer substrates are essential for devices to overcome the mismatch between the hard, planar surfaces of semiconductor wafers and the soft, curvilinear tissues of biological systems [64,65].…”

Applying Nanomaterials to Modern Biomedical Electrochemical Detection of Metabolites, Electrolytes, and Pathogens

“…A trend in biomedical sensing devices is to achieve self-sustainable sensing devices [96]. This would need a system that contains a continuous and effective energy sources.…”

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“…Apart from flexibility, self-healing ability of materials is interesting to integrate with soft or modern electrochemical sensors [96,116]. An example of a wearable potentiometric pH sensor was proposed in form of cables which can easily be knitted into textile ( Figure 5D) [115].…”