Lu Rahman looks at some of the latest antimicrobial offerings for medical device manufacture.
Chelsea Whyte in the New Scientist described a study carried out by the University of Hong Kong where volunteers used the subway for 30 minutes and then swabbed their hands. Upon analysis of the swabs, “the majority of microbes they picked up were common skin bacteria, and the most abundant non-bacterial organisms were yeasts. In the morning rush hour, 140 species were detected, but by evening, many of those were no longer detectable and the populations of just 48 species had expanded to cover the entire system.”
The article also described how “the team also swabbed train surfaces, but they didn’t find much microbial DNA – perhaps because of the antibacterial coating that is applied to the surfaces of the Hong Kong subway”.
Antimicrobial products make a difference. Infection control is big business. As the pharma sector seeks ways to tackle antimicrobial resistance (AMR), the medical device sector is developing ways to curb the spread of harmful bacteria in the healthcare environment. The opportunities are evident. According to Marketsandmarkets, which projects the antimicrobial coatings market to reach $4.19 billion by 2021: “Healthcare is the key application of antimicrobial plastic... It is the largest application in the antimicrobial plastic market and accounts for more than one-third share of the market. The Asia-Pacific region dominated the market for health care application of antimicrobial plastic, followed by North America and Europe.”
Marketsandmarkets lists leading players in the market as including: Bayer MaterialScience, The Dow Chemical Company, Clariant, Lonza Group, Parx Plastic, King Plastic Corporation, Biocote, Milliken Chemical and PolyOne Corporation.
A specialist in polymer solutions for healthcare markets, Foster recently introduced Combat antimicrobial masterbatches for blending with medical device polymers. Components made with these antimicrobial polymer blends kill bacteria that lead to infections, including methicillin-resistant staphylococcus aureus (MRSA) and carbapenem-resistant enterobacteriaceae (CRE).
Foster says that according to a survey by the Center for Disease Control (CDC), 4% of inpatients in US acute care hospitals contract at least one healthcare associated infection. Device associated infections accounted for one in every four infections. In-dwelling devices, such as central venous catheters, are particularly susceptible to bacteria colonisation which can enter the bloodstream.
Ionic silver is successful at killing bacteria and preventing colonisation. Additives based on this chemistry are commonly melt blended directly into medical polymers for the manufacture on antimicrobial device components. However, evaluation of multiple custom compound formulations can be costly.
“Combat master batches are available in quantities as low as two pounds to minimise costs for initial evaluations,” said Larry Johnson, executive vice president for Foster Corporation. “With let-down percentages of 2-10%, depending on the polymer and applications, these small order quantities allow engineers to test several antimicrobial formulations from a single order quantity.”
Parx Plastics sees an important role for its technology in the quest to tackle AMR. Its antimicrobial technology for plastics and polymers is derived from bio-mimicry, a patented biocompatible technology inspired by nature. The technology creates an intrinsic immune system in plastics that makes the surface resistant to biofilm formation and bacteria growth.
With a focus on infection prevention Parx Plastics believes it wise to consider the antimicrobial technology to use. Roughly all of the technologies today, it says, rely on a migration principle. They have some active (and often toxic) substance migrating from the surface to act against bacteria. However, these uncontrollable technologies contribute to AMR as their functional substances can end up anywhere in the environment of the product creating more places for only the resistant bacteria to survive and proliferate. Taking AMR seriously, says Parx, means applying the technology only there where you want to use its benefits.
“This is really where our technology stands out,” explains Michael van der Jagt, CEO of Parx Plastics. “First of all our technology uses a body’s own element and on top of that our technology knows no migration, the performance is inert and intrinsic to the material surface. That means you have a targeted performance only on the surface where you want it and it does not end up elsewhere.”
Van der Jagt envisions this technology will be of particular use in high-infection risk applications with permanent implants such as in the orthopaedic field.