The hygiene and reliability challenge

How glass-sealed components enable the design of fully autoclavable, long-lasting medical devices

How glass-sealed components enable the design of fully autoclavable, long-lasting medical devices

Hygiene is an overarching topic in the medical arena. It’s not just an expectation, but a requirement. Clean, properly sanitized devices are a fundamentally important starting point for any medical procedure. From basic check-ups to hours-long surgeries, every device put into a doctor’s hands must be sterile to ensure patient safety.

The need for hygienic, sterilized devices is ubiquitous in medical facilities. But how is it achieved? There are several avenues for this: first, the use of disposable devices. One-time usage eliminates risk of cross-contamination. The devices are opened new, used for a single procedure, and then discarded. However, this process can be inefficient and generate considerable waste. For more complex devices, continuous replacement comes at a potentially significant cost – not to mention the headache of monitoring supply and placing restocking orders on a constant basis.

The other method involves sterilizing the device. One of the most tried and true processes to reliably kill bacteria is steam sterilization. Due to the penetrating properties of water vapor, microorganisms are destroyed by the irreversible denaturation of enzymes and proteins.

Between procedures, devices are cycled through an autoclave at high temperatures and pressure in a humid environment with sanitizing agents. While effective at eliminating potential contaminants, the harsh process takes its toll on the devices themselves as well as their built-in components. As such, components that can survive this process repeatedly are a necessity, ideally for many cycles to enable sterilization as easily and often as possible. This especially applies to electronics and semiconductor components that are extremely sensitive to even small amounts of water vapor and must be fully protected from moisture intrusion.

Components encapsulated with vacuum-tight packaging can accomplish this: using inorganic materials such as glass, ceramics and metal, they maintain integrity and can withstand thousands of sterilization cycles, representing an answer to the challenge of durability in the autoclave for medical devices.

Solidur® LEDs and Eternaloc® electrical connectors from SCHOTT are two such examples of glass-sealed components that can be utilized in medical devices. They enable innovation with custom designs and unique device integration possibilities while standing up to the harsh conditions of the autoclaving process.

Vacuum-tight LEDs enable robust and clean illumination

Doctors and dentists have hailed the arrival of autoclavable LEDs that can bring the light source directly to treatment sites. They eliminate the shadows of overhead lights and offer clear and convenient visibility that is almost second nature to utilize.

LED lighting offers numerous advantages to medicine and dentistry: these light sources operate at low temperatures, are extremely power-efficient, and provide brilliantly bright and crisp illumination at the right color. However, the heat and moisture of the autoclave are a threat to conventional LEDs.

Polymer sealing materials, typically used to encapsulate conventional LEDs, do little service for the protection of the sensitive internal electronics. The sealing points of LED lighting modules are of critical importance for the protection of the internal semiconductor components. Even after just one cycle in the autoclave, organic polymer materials can begin to break down. The weakened seal allows the potential for moisture permeation into the module, a fault that can lead to premature failure for the LED chip inside.

Glass-to-metal sealing technology represents an answer to the challenge of steam sterilization for LED modules integrated directly into medical and dental devices. SCHOTT Solidur® LEDs are a line of customizable High Brightness (HB), autoclavable LEDs capable of withstanding over 3,500 autoclaving cycles in at 273°F temperatures and two bars of pressure. The hermetically sealed housings of Solidur® LEDs are made of inorganic materials, including specialty glass or ceramics – neither of which age or break down over time. As such, the LED packaging remains gas-tight and water-tight, fully protecting the internal LED chips from corrosive damage caused by moisture permeation.

These versatile light sources can be incorporated into any number of devices, even ones that have never previously had an integrated light source due to design limitations or autoclaving requirements. This includes endoscopes such as laparoscopes and otoscopes, or surgical tools, drills, and dental mirrors, among others. When Solidur® LEDs are integrated at the tip of an instrument, the direct proximity to the treatment site can bring illumination to previously unreachable areas and reduces shadows in the process.

Gas-tight connectors: Reliably supplying power and data when needed most

Much like illumination provided by LED lighting modules, reliable electrical and data connections are another intangible but supremely important element for smooth and successful procedures in medicine and dentistry.

Electrical connectors perform the task of supplying power and valuable data signals during procedures. Their flawless functionality is essential: a faulty connection point can lead to device failure, compromising the success of procedures and even patient safety.

Sterilization requirements present just as much of a challenge for medical connectors as they do for LEDs. The electronics inside modern medical appliances need unwavering protection from moisture, chemicals, heat, and pressure found in the autoclave. It is imperative that the connectors do not become a weak point in the equation. However, when polymer or epoxy-based sealing materials are used to seal the electrical conductors of a connector, this is exactly what can happen.

Polymers or epoxy resins in medical connectors are not adequate barriers for the protection of electronic components found in medical devices. During the autoclaving process — and especially after repeated cycles — polymer-based feedthrough seals in connectors can become permeable, allowing moisture to bypass the brittle shield and damage internal electronic components.

Medical connectors constructed of inorganic, non-aging materials provide adequate protection for expensive medical instruments including laparoscopes, arthroscopes, robotic surgery tools, and robotic sensor systems for the calibration of medical devices. SCHOTT Eternaloc® glass-to-metal sealed connectors offer a resilient and dependable option capable of undergoing more than 3,500 autoclaving cycles.

These vacuum-tight connectors can be custom-designed in a number of shapes, sizes, and pin configurations to meet a wide variety of requirements for integration in medical devices with electrical and data supply infrastructure that require repeated sterilization.

Unleashing innovative designs in an ever-evolving marketplace
Reliability and longevity are staple qualities for devices in medicine and dentistry that elevate their value and build a reputation of trust amongst purchasers and clinicians. Glass-to-metal sealing technology, found in Solidur® LEDs and Eternaloc® connectors, opens new design possibilities for medical device engineers to create opportunities for a competitive advantage in the marketplace with distinct, cutting-edge designs – all while meeting strict regulatory requirements for repeated steam sterilization.

As medical instruments and technologies grow more sophisticated and complex, it is increasingly important to guard sensitive components from the autoclaving process while supporting their longevity. Glass-to-metal sealing, offering unparalleled protection for sensitive electronics, offers a way.

May 30, 2018


Kevin Waxman
Electronic Packaging
SCHOTT North America, Inc.