Manufacturing a Guidewire (Mandrels, Tips and Coatings)

Guidewires are constructed of an inner core wire, which is sometimes called a mandrel, and an outer coil. Core wires are typically made out of Stainless Steel or Nitinol but Modern Grinding has worked with an endless amount of materials in guidewire research and lab settings. All else equal, stainless steel guidewires are stiffer than nitinol wires. Super-Elastic Nitinol (NiTi) material can help resist kinking and maintains its shape throughout a procedure. Guidewire diameters are manufactured to achieve an optimum level of flexibility, stiffness, or floppiness depending on vascular navigation needs.

Guidewire Tips

Normally the core wire of a guide wire does not extend all the way to the tip of the guidewire, instead we grind guidewires to a tip and then coils and coatings are used to extend the tip and maximize maneuverability. Modern Grinding works off of specifications to craft the tip of the outer coil of the guide wires into j-curved, angled, and straight tips. “Floppy” guidewire tips are adaptable and not designed to retain a formed shape.

Guidewire Coating

Guidewire outer coils may also be plated with a heavy metal such as gold or platinum. Beyond metal plating on guidewires, most have some form of antifriction coating. TFE coating has been shown to reduce the coefficient of friction for stainless steel wires to 1/2 the uncoated value, and a silicone coating can reduce it to 1/6 the uncoated value. Many newer wires are coated with a hydrophilic polymer similar to silicone. Guidewire coatings and plates that we have used include PTFE, Hydrophoilic, Pebax, TFE, Teflon, Radiopaque, Tungstun, Polyurethane and many others.

This blog post was adapted with content from – http://www.ctsnet.org/portals/endovascular/nutsbolts/article-3.html

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