Bacteria and the risk of infection is a significant concern for medical plastic components inserted into the body. Applications of greatest concern are those exposed to bodily fluid for extended periods of time, including but not limited to catheters, wound dressings, hospital bedding, surgical drapes, and hospital gowns.
In terms of medical catheters, the risk of infection is particularly high for those tubes and components that are left in place for three or more days (i.e. in-dwelling catheters). In this case, handling and exposure of these devices can influence time of onset and severity of infection. Infections often occur at incision points, where catheters enter the blood vessel and bacteria is introduced into blood stream.
The general mechanism of infection related to in-dwelling polymers can be summarized as follows: Free floating microorganisms attach to the plastic surface. Colonies of bacteria grow and permanently anchor to plastic surface. A biofilm formation results as colonies grow and mature. Infection occurs when biofilm detaches from plastic substrate.
Foster Antimicrobial Technologies
Foster has developed a range of antimicrobial technologies using both silver and polymer-based solutions, designed to fight infection and prevent the development of bacteria on contact surfaces. Formulations are custom developed to achieve specific application requirements.
Silver ions (a by-product of oxidation) have inherent antimicrobial properties and a history of use in medical applications. These ions attack microbial targets, not only limiting the spread of microbial growth but simultaneously resisting formation. Other materials including carbon and copper, may be added to polymers to tailor oxidation for efficacy and duration.
Agion™ Antiomicrobial Technology – Developed by Sciessent, Angion™ incorporates both silver and copper in a zeolite carrier to fights cell growth by preventing respiration (inhibit transport functions in the cell wall), inhibiting cell division (reproduction), and disrupting cell metabolism.
Foster Combat™ Antimicrobial Master Batches – Foster has designed and developed a line of silver based masterbatches using high loadings of Sciessent Agion™ in a universal polymer matrix. These are dry blended with unmodified polymers at letdown percentages from 2-10%, depending on the polymer and application. These include thermoplastic polyurethane (TPU) used for indwelling catheters, and acrylonitrile styrene butadiene (ABS) and polycarbonate (PC) used for device handles, bedrails and diagnostic equipment housings.
Foster Quaternary Ammonium Compounds – Quaternary Ammonium Compounds are polymer-based antimicrobials that rely on positively charged polyatomic ions to fight infection in medical device applications. These “quats” are blended with polymers to form a permanent bond and retain their ionic charge independent of solution pH. This revolutionary technology offers considerable promise in cost and performance relative to other solutions, particularly silver.