Weaving Off‐The‐Shelf Yarns into Textile Micro Total Analysis Systems (μTAS)

Abstract

Textile based biosensors have garnered much interest in recent years. Devices woven out of yarns have the ability to be incorporated into clothing and bandages. Most woven devices reported in the literature require yarns that are not available on an industrial scale or that require modifications which are not possible in large scale manufacturing. In this work, commercially produced yarns are taken without any modification or cleaning, and developed woven textile diagnostic devices out of them. The yarn properties that are important to their function within the device have been characterised and discussed. The wicking ability and analyte retention of Coolmax yarns, developed to wick sweat in mass produced sportswear, are determined. The electrochemistry and functionalizability of Au coated multifilament yarns are investigated with no cleaning or treatment and are found to have as good a thiolate self‐assembled monolayer (SAM) coverage as cleaned Au disk electrodes. The feasibility of using these yarns is established off the shelf, with no cleaning, to make woven capillary force driven microfluidic devices and three electrode sensing devices. A proof of principle three electrode system capable of detecting clinically relevant concentrations of glucose in human sweat is reported.

Thread-based wearable devices

“…44,45 There are two principal textile manufacturing methods for the integration of these functions: the first is additive fabrication such as printing on textiles or embroidering threads into textiles to add function (Figure 4a-b) 45,46 and the second is a bottom-up approach where all base functions are embedded at the fiber level, and weaving or knitting is used to design and create the µTAS (Figure 4c). 47 Although both of these fabrication approaches offer low cost and robust wearable biosensors without the need for undergoing complicated microfabrication processes at cleanrooms, the first approaches, including screen-printing 48 and embroidery techniques, 46,49 are widely used due to their potential of scalability, and therefore, are amenable to industrial applicability.…”

“…Glucose oxidase is bound to the gold filaments through self-assembled monolayers to allow glucose detection in human sweat. 47 Liu et al developed a biomimicking sensing suture (BBS) for simultaneous wound monitoring, wound healing and antibacterial activity. Inspired by spider-silk fiber, the authors fabricated core-shell multilayered sutures where the silk-based core fiber provided a mechanical framework of the suture and the three layers in the shell consisted of a conductive CNT for strain sensing, growth factors for in situ delivery, and quantum dots for optical monitoring of drug release (Figure 6a).…”

“…(c) Schematic illustration of a woven µTAS device with fluidic Coolmax threads, acting as microfluidic channels, interwoven into gold coted yarn, acting as electrodes. Glucose oxidase is bound to the gold filaments through self-assembled monolayers to allow glucose detection in human sweat 47.…”

Electroanalytical Paper-Based Nucleic Acid Amplification Biosensors with Integrated Thread Electrodes

“…Off-the-shelf gold plasma-coated threads are highly flexible and conductive fiber electrodes that do not require any cleaning step before SAM modification, making them suitable for mass-produced electrodes as we recently reported. 29,52 Here, we report a multilayer paper-based electrochemical DNA sensor with integrated electrodes in the form of gold threads. This 3D μPAD shown in Figure 1 includes different layers (hollow channels, movable wax barriers, and movable absorbent pad) allowing time-sequence retentions, flow, and absorption of solutions to conduct a sandwich hybridization assay (SHA) with minimum user intervention.…”

Macromolecular Bioelectronics

“…Hamedi and colleagues report the woven textile diagnostic devices based on commercially produced yarns without any modification or cleaning processes. [ 26 ] Three‐electrode sensing devices were fabricated by weaving the Coolmax® yarns (originally developed for sweat‐wicking sportswear). They confirmed that Au‐coated multifilament yarns exhibit good functionalization and electrochemical activity comparable to cleaned Au disk electrodes.…”