Direct Printed Silver Nanowire Strain Sensor for Early Extravasation Detection

Area of Science:

• Biomedical Engineering
• Materials Science
• Wearable Technology

Background:

• Extravasation, a serious complication during intravenous therapy, requires early detection to prevent tissue damage.
• Current detection methods can be delayed, leading to adverse patient outcomes.
• There is a need for sensitive, real-time monitoring solutions for extravasation events.

Purpose of the Study:

• To develop a wearable sensor patch for the early detection of extravasation.
• To utilize a simple, direct printing process for fabricating the sensor.
• To achieve accurate localization of extravasation events.

Main Methods:

• Formulation of silver nanowire (AgNW) ink with specific rheological properties for printing.
• Controlled printing of AgNW patterns on flexible plastic sheets to enhance resistance change under strain.
• Fabrication of a resistive strain-sensing device on a stretchable film for skin attachment.
• Array printing of millimeter-sized sensors for multi-point detection.

Main Results:

• The printed sensor pattern effectively detected directional forces via resistance changes.
• The sensor demonstrated high sensitivity with a gauge factor (GF) of 100 at 50% strain.
• Millimeter-sized sensors in an array successfully detected small extravasation volumes (<0.5 mL) at accurate locations.

Conclusions:

• A wearable sensor patch fabricated by direct printing offers a promising solution for early extravasation detection.
• The sensor's high sensitivity and ability to detect small volumes enable timely intervention.
• This technology has the potential to improve patient safety during intravenous therapy.