Micro-sensor stitches deliver in-vivo diagnostics

October 25, 2016 // By Julien Happich
Researchers from Tufts University have devised a tool kit to experiment with thread-based microfluidics, sensors and electronics that could be used to monitor tissues in-vivo. Threads are something surgeons are familiar with and are flexible enough to comply with stretchable skin or soft organs during surgery.

With his team, associate professor Sameer R. Sonkusale and principal investigator at Tufts' NanoLab experimented with sewing threads from different materials, coating them with conductive materials such as carbon nanotubes and infusing them with various chemical reagents.

Sewing specific thread combinations and connecting them to reading electronics, the researchers were then able to monitor electrical signals, either signalling strain, temperature, or even sensing in-vivo subcutaneous chemical markers to diagnostic particular patient conditions. In some cases, they also leveraged the wicking property of threads to design three-dimensional multi-reagent microfluidic circuits.

The thread-based diagnostic device (TDD) platform, as they describe it in Nature's Microsystems & Nanoengineering journal in the paper "A toolkit of thread-based microfluidics, sensors, and electronics for 3D tissue embedding for medical diagnostics" combine nanomaterial-infused conductive threads connected to a flexible surface readout electronic circuitry, for signal conditioning and wireless transmission.

They fabricated strain sensors out of stretchable rubber fibres coated with carbon nanotubes and silicone (monitoring the thread's electrical resistance), which they suggest, could be used to monitor wound healing or muscle strain experienced due to artificial implants.