Self-assembling monolayer end groups (SAMEs) are an emerging two-dimensional nanotechnology used to control the surface properties of medical devices molded from plastic materials rendering them antimicrobial. Bulk polymer properties are established largely by the polymers backbone structure/chemistry while the terminal SAME groups which are appended to the backbone chain dictate the surface properties. A polyurethane material with permanently bonded antimicrobial surface properties has been developed by DSM PTG (Polymer Technology Group), part of DSM Biomedical. The polymer with surface-active alkyl ammonium chloride end groups has demonstrated antimicrobial action against gram-positive bacteria in a range of laboratory studies. Very small amounts of biologically active end groups are permanently incorporated into the polymer during its synthesis. After being extruded or molded into a medical device, the new material modifies its own surface as a result of the polymer's surface activity and self-assembly of its novel end groups. In this way the antimicrobial groups are concentrated on the surface where they are needed. No secondary coating processes or treatments are required to provide the necessary antimicrobial properties, which reduces manufacturing times and the cost of goods.
DSM PTG has similarly modified thermoplastic polycarbonate urethanes. Various polymers that involve other antimicrobial self-assembling monomers and groups are also being investigated for a range of medical device applications. Mixed head groups are also possible for defense against multiple pathogens.