FIG. 11.

Fibrous implantable sensors. (a) Optical image of diamond coated carbon fiber electrode encapsulated in the glass pipette. The inset shows the SEM image of carbon fiber at the tip of the electrode. (b) SEM image of diamond-coated carbon fiber. (c) The cyclic voltammetry curves obtained in the presence of varying concentrations of dopamine. (a)–(c), Reproduced with permission from Hejazi et al., Biomaterials 230, 119648 (2020). Copyright 2020 Elsevier.¹⁶⁵ (d) The cross-sectional schematics of the fiber made from graphite and conductive polyethylene composite. I SEM cross-section of the fiber with two electrodes highlighted in yellow and a microfluidic channel highlighted in red. (f) Continuous monitoring of lactate in vivo in a mouse model. (d)–(f) Reproduced with permission from Booth et al. Anal. Chem. 93, 6646 (2021). Copyright 2021 Authors, licensed under a Creative Commons Attribution (CC BY) license.¹⁶⁹ (g) Schematics of core-shell structure of conductive nylon fiber with multi-layer coatings. (h) Weaving of fabric organic electrochemical transistors, sensitive to a variety of chemicals. (i) Current response of fabric glucose sensor. (g)–(i) Reproduced with permission from Yang et al., Adv. Mater. 30, 1800051 (2018). Copyright 2018 John Wiley and Sons.¹⁷⁰ (j) Calcium ion sensitive single-ply sensing fiber (SSF) composed of CNT fiber, PEDOT:PSS, and an ion selective membrane. (k) SEM image of SSF and its surface morphology. (l) and (m) On-body measurement of (l) glucose and Ca²⁺ (m) realized by SSFs and comparison with collected blood samples. Scale bars, 25 (left) and 1 μm (right). (j)–(m) Reproduced with permission from Wang et al., Nat. Biomed. Eng. 4, 159 (2020). Copyright 2020 Springer Nature.¹⁷¹