Whitepaper explores the benefits of in-house microbial-controlled clean rooms

Microelectronics technology is increasingly ubiquitous, even within the human body, as medical researchers develop new approaches to monitoring and treating a growing array of illnesses and injuries. A variety of implantable medical devices are now used routinely, ranging from intraocular lenses to EEG recorders and many others. The companies that design these devices require specific capabilities and qualifications from a potential medical device manufacturer.

These requirements typically cover topics like experience in medical device manufacturing, the types of equipment necessary to manufacture, assemble, and package the product, parts tracking methods, employee qualifications and/or specialised training, required industry and governmental certifications, etc. However, as comprehensive as these requirements might appear, some of them fail to include an aspect that is critical for some categories of medical microelectronics device manufacturing: a microbial-controlled clean room.

A microbial-controlled clean room is important because it allows medical device manufacturers to handle the complete manufacturing process, thereby shortening the supply line, saving time and containing cost. This is accomplished by eliminating the need to ship finished devices to a third-party vendor for cleaning or packaging prior to sterilisation. Device sterilisation alone is not enough. For microelectronic devices designed for either permanent or temporary implantation in the human body, the use of a microbial-controlled clean room to control the microbial level during final device assembly and pouching is essential to avoid exposing patients to danger. Other features of the microbial-controlled clean room include:

• Minimal paper is allowed in the clean room because wood pulp fibres shed from paper are a potential source of contamination.
• All component routing and tracking information is provided in electronic form.
• Clean room technicians follow standardised procedures, e.g. proper gowning procedures, use of antiseptic foam on their gloves before entering, etc.
• Technicians also follow schedules for cleaning, HEPA filter maintenance, etc. An external auditor checks particulate counts annually. Tables, walls and floors are swabbed biweekly and the residue is cultured to check for the presence of bacteria, yeasts and molds.

The clean room houses a variety of testing, assembly, and packaging equipment, including adhesive dispensing equipment for sealing devices and a helium leak tester for assessing their hermeticity, a load tester to confirm sensors are reading the applied loads properly and a heat sealer for the plastic pouches in which finished devices are packed prior to EtO sterilisation.

Valtronic operates a variety of clean room classes in its manufacturing facilities around the world, including the United States, Switzerland and Morocco. The newest one is an ISO Class 8 microbial-controlled clean room located in the company’s Solon, Ohio, manufacturing facility. This clean room combines temperature, humidity and contamination controls designed to prevent both particulates and microbes (dust, pollen, fibres, germs, yeast, molds, etc.) from making contact with implantable devices during final assembly and pouching, prior to EtO sterilisation.