Self-Powered Coiled Carbon-Nanotube Yarn Sensor for Gastric Electronics

Area of Science:

• Biomedical Engineering
• Materials Science
• Gastroenterology

Background:

• Gastric peristaltic contractions, crucial for digestion, occur rhythmically at ~3 cycles/min in humans.
• Gastroparesis involves disrupted gastric electrical signals, leading to impaired motility.
• Current gastric stimulators require improved sensors for real-time monitoring of gastric contractions.

Purpose of the Study:

• To evaluate a novel coiled carbon-nanotube (CNT) yarn as a self-powered sensor for monitoring gastric deformations.
• To assess the performance of the CNT yarn sensor in biological fluids and an artificial gastric system.
• To determine the potential of the CNT yarn sensor for real-time gastric monitoring and adaptive electrical stimulation.

Main Methods:

• Fabrication of a coiled CNT yarn capable of converting mechanical motion to electrical energy via stretch-induced capacitance changes.
• Performance evaluation of the CNT yarn sensor under sinusoidal stretching in biological fluids at various frequencies and strains.
• Testing the sensor's response to periodic volumetric changes in an in vitro artificial gastric system.

Main Results:

• The CNT yarn consistently generated peak-to-peak open-circuit voltage (OCV) under sinusoidal stretch (up to 30% strain) at frequencies below 0.1 Hz.
• OCV generation increased with strain, showing a near-linear relationship with balloon volume in the artificial gastric system at 2, 3, and 4 cpm.
• The sensor demonstrated the ability to monitor frequency and amplitude of volumetric changes and generate electrical power.

Conclusions:

• The self-powered CNT yarn sensor can effectively monitor gastric deformations by detecting changes in frequency and amplitude.
• This technology holds promise for real-time, adaptive gastric electrical stimulation therapy in gastroparesis patients.
• The CNT yarn sensor offers a potential solution for improved monitoring in current gastric stimulator systems.