Flexible Magnetoresistive Sensors for Guiding Cardiac Catheters

Abstract

Cardiac catheterization is a procedure, in which a long thin tube that is called a "catheter" is inserted into the heart for diagnosis or treatment. Due to the excessive use of x-ray doses and contrast agents for orientation detection during the surgery, there is a need to find a better alternative. This paper presents magnetic tunnel junction sensors on flexible Si attached to the catheter tip for orientation detection during minimally invasive surgeries. Due to the small size of catheters, extreme minimization in terms of size, weight, thickness and power consumption is needed for any device implemented on it. The fabricated flexible magnetic tunnel junctions fulfill those requirements with size, thickness, weight and power consumption of 150 m 2 , 12 m, 8 g and 0.15 W, respectively, while still providing a high sensitivity of 4.93 %/Oe. The sensors can be bent with up to 500 m in diameter, which is more than needed for even the smallest catheters of size 1 mm (3 Fr) in diameter. This result is a stepping-stone towards the development of a versatile and low-cost smart catheter system that can help surgeons navigate inside the heart while minimizing the side effects.

Flexible Magnetic Field Nanosensors for Wearable Electronics: A Review

“…Several groups have reported on flexible MTJ sensors prepared by backside etching the rigid Si substrate to below 20 μm followed by transferring the thin MTJ film to a flexible substrate or a needle-like tip for different application purposes, − similar to the method used in Figure (B). Loong et al deposited CoFeB/MgO/CoFeB (FM/I/FM) MTJs on conventional, thermally oxidized Si wafers and then etched away the Si substrate and transferred the MTJs onto flexible PET substrates .…”

“…Remarkably, this sensor operates at an incredibly low power consumption of approximately 80 nW. Hawsawi et al and Amara et al presented flexible MTJ sensors for the purpose of guiding cardiac catheters. , The research focused on integrating MTJ sensors onto flexible Si, enabling their attachment to the tip of the catheter for orientation detection during minimally invasive surgeries. Given the small size of catheters, it is of utmost importance to significantly reduce the size, weight, thickness, and power consumption of any device integrated onto them.…”