• Published February 20th, 2025

The Power Lies Within: Embedded conductors for space-saving guide wire design

Adam J. Griebel, Cody David, Jeremy E. Schaffer

Guidewires, and similar wire-based components used for interventional access, are an essential tool in countless minimally invasive medical procedures. These components provide a precise pathway for delivery of catheters, stents, and other life-saving devices into the body [1].  Some procedures and devices benefit from sensors located at the tip of the wire or catheter and this often requires running additional insulated electrical leads down the length of the core guidewire [2-3]. One problem is that these additional parallel components, especially in small components for difficult anatomy, end up consuming precious intraluminal space [4].

Fort Wayne Metals R&D Team has recently produced a prototype “multichannel” wire with three electrically isolated wires embedded within the main body (Figure 1). Here, the main body is 304V stainless steel, the insulator material is magnesium oxide (MgO), and the inner filaments are 316LVM stainless steel. This prototype was successfully drawn to 0.017” and was then thermomechanically straightened, resulting in a high strength (360 ksi / 2500 MPa) and exceptionally straight wire with good torque control characteristics down a tortuous path. 

Figure 1. 0.017” (0.43 mm) diameter multichannel guidewire. The main body is 304V, and the three inner wires are ~0.0016” (0.04 mm) 316LVM. A layer of MgO powder provides electrical insulation.

To evaluate cross-sectional uniformity and verify insulation integrity, 15 cross sections from both ends of the wire were imaged. The inner wires were slightly and consistently elliptical (e = 0.69 ± 0.05). No instances of contact between the 316LVM inner wires and the 304V main body were found. The minimum MgO thickness observed in any cross section was 0.00025” (6.3 microns).

There is great freedom in the number, size, and location of leads inside the main wire that are possible, whether it be a simple coaxial arrangement or several smaller leads distributed around a larger center lead. If you think your next project could benefit from a wire of this type, reach out to us at RDTeam1@fwmetals.com and we’ll see what we can do for you.

References

[1] Kipling, Mike, Aza Mohammed, and Robert N. Medding. "Guidewires in clinical practice: applications and troubleshooting." Expert review of medical devices 6.2 (2009): 187-195.

[2] Tulkki, S., & Tenerz, L. (2010). U.S. Patent No. 7,645,233. Washington, DC: U.S. Patent and Trademark Office.

[3] Thornton, Paul P., Thomas J. Gaskin, and Finbar Dolan. "Guidewire sensor device and system." U.S. Patent Application No. 12/786,849.

[4] Goosen, Hans FL. "Silicon sensors for catheters and guide wires." BioMEMS and Smart Nanostructures. Vol. 4590. SPIE, 2001.

© 2025 Fort Wayne Metals Research Products, LLC. All rights reserved. Published February 20, 2025

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Disclaimer: Our monthly highlights are sneak peeks of what our R & D department is working on. This does not mean we have what is referenced above ready for manufacturing.