Effective Alternative to Silicone-Jacketed Cables and Cable Assemblies

By Kevin Depratter | April 12, 2022

A mainstay of medical device design, silicone jacketing protects cables from the hazards that medical technologies face in clinical care settings. It’s not a perfect material, though. New alternatives address silicone’s common shortfalls.

Silicone is a widely used cable-jacketing material for medical device components. Commonly used in medical tools, hospital equipment, and surgical devices, silicone is flexible and smooth while providing thermal stability. When produced for medical-grade products, these qualities allow the material to meet FDA, USP Class VI, and ISO 10993-5, and 10993-10 biocompatibility requirements.

While medical-grade silicone is one of today’s most prevalent materials for healthcare device components, it has its downsides. Producing sturdy, medical-grade silicone can be a long and costly process. As a thermoset material, silicone must go through a curing process. This adds significant cost and a longer lead time to production. In addition, the fast-paced hospital and clinic environment puts silicone cable systems through repetitive use, constant movement, and at risk of damage from heavy rolling equipment. These environments increase a cable’s vulnerability to cuts, crush, and abrasion where silicone has limited durability; this can decrease its lifetime.

A USP Class VI alternative that overcomes silicone downsides

As medical devices, industrial control systems, and critical communication tools grow more complex, electrical component manufacturers are developing innovative solutions that integrate new technologies with next-generation materials. One such material advancement is the development of a medical-grade cable alternative that offers the benefits of silicone and overcomes its downsides.

silicone-jacketed cable in medical applications

Free of bisphenol A, phthalates, and halogen, BioCompatic® silicone alternative is compliant to USP Class VI, ISO 10993-5 & 10, RoHS3, and REACH, and is suitable for a wide range of medical applications, including patient monitoring cables, endoscopic reusable/sterilized assemblies, imaging cables, diagnostic tools, and catheter applications.

Northwire, a design engineering and custom cable manufacturer, developed BioCompatic silicone alternative, a USP Class VI medical cable jacketing and injection-moldable and over-moldable material. BioCompatic does not have the lengthy curing process silicone requires; this reduces production time and costs.

Chemical Resistance Testing

When introducing a silicone alternative, cable manufacturers must conduct rigorous testing to confirm durability, reliability, and performance. A key metric Northwire engineers used when testing BioCompatic cables was the silicone alternative’s resistance to the most common hospital disinfectants and concentrates, such as betadine, Cidex OPA, Clorox Healthcare Bleach, Virex II 256, isopropyl alcohol (IPA 99%), and hydrochloric acid (HCl, 36%), to name a few. Typically, in a hospital or clinic setting, medical cable and devices are exposed to chemical substances for 10 minutes. However, Northwire engineers tested BioCompatic for chemical resistance by immersing the silicone alternative material for a full 24 hours.

Crush Resistance Testing

Day-to-day hospital use puts medical device cable to the test. In addition to chemical resistance, engineers test against common hospital environments factors, such as crush resistance. When a 200-pound hospital gurney rolled over a silicone cable assembly, tests showed the cable failed in fewer than 9,300 cycles. In the same gurney rollover tests, BioCompatic silicone alternative cable sustained over 186,100 cycles.

Sterilization Resistance Testing

Steam autoclave is a common method for sterilizing medical devices. The high pressure, high temperature steam effectively sanitizes hospital supplies, but can negatively affect a tool’s appearance and performance over its “cycle life.” For many applications, medical-grade cable must undergo rigorous sterilization to avoid contamination by bacteria, viruses, and other pathogens.

During testing, BioCompatic silicone alternative retained full tensile strength and elongation after enduring over 500 steam autoclave cycles at 134 °C, including continuous operating temperatures to 105 °C, as well as resilience after gamma and ethylene oxide (ETO) sterilization, and hydrogen peroxide sterilization.

Biocompatible and Ergonomic

Intense and demanding medical procedures require medical device tools that are both biocompatible to patients and ergonomic for health professionals to use. Effective cable design systems promote ease of use to the surgeon or healthcare professional without tangling and twisting. This reduces hand fatigue to the user and prolongs the life of the cable system.

It is critical to specify a cable jacketing material that can conquer electrical, environmental, and ergonomic extremes and provide a ruggedized solution to complex and commonplace medical device cabling challenges­. Proper material selection contributes to the durability and long life of the product.

Amid longer lead times, material shortages, limited durability, and other challenges to silicone cable jacketed components, alternative materials for medical-grade cable jacketing give OEMs an important tool to continue to innovate quality medical devices and equipment.

To learn more, visit Northwire.com.

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Kevin Depratter
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