Super Surfaces: Pulverizing Polymers Out-Muscle Pesky Pathogens

The focus of polymer development is on two particular classes of compounds for materials applications, the polymethylacrylates and polynorborenenes. A small phenylalkyne oligomer, with broad-spectrum antimicrobial activity and which is easily synthesized, is also suitable for materials applications.

All AAC monomers and polymers compounds are produced from commercially available starting materials. Methylacrylate polymer synthesis is a one-pot, one-step co-polymerization of two monomers; one functionalized monomer bearing a positively charged side group and the other bearing a hydrophobic side group. The resulting random co-polymer is amphiphilic and antimicrobial activity is dependent on the percent composition of each of the methacrylate monomers. Polynorborenene polymers are made using a co-polymerization process with mixtures of two monomers that bear positively charged and hydrophobic side groups, or a polymerization process using one type of monomer that bears both positively charged and hydrophobic side groups.

AACs in development as drugs are synthesized as small molecules, while those used in industrial materials are prepared as polymers. The polymers are formulated into materials in one of several ways. Pure AAC polymers may be ground into fine powders and added, in low concentration, to polymer blends to create bulk polymer (e.g. polymethacrylate) with excellent antimicrobial properties. Another possibility is to co-polymerize AAC monomers with a suitable monomer to form a homogeneous material that is inherently bactericidal.

Many types applications are feasible for polymeric AACs within the following product classes:

• Biomedical Applications: intravenous tubes, catheters, antiseptic lotions, bandages, implantable joints, medical devices, surgical gloves;
• Industrial Applications: clothing, paper, paints, construction materials (walls, floors, benches), antifouling coatings, hospital surfaces;
• Consumer Products: cosmetics, personal care products, toilet seats, toys, bedding, towels, carpeting.

AACs show tremendous potential as materials for manufacturing a broad range of food-contact products, including work surfaces, processing equipment, utensils and implements, handling and storage equipment, and packaging. Since these materials may be formulated as bulk polymers/copolymers, polymer additives, or films, AAC could be available for almost any plastic product that comes into contact with food, from the processing plant to the dinner table.

Conclusion

AACs are still very much development-stage products and work in progress. Applying new materials to critical applications like food handling and medicine requires review and/or registration with appropriate regulatory agencies, and a good deal of scientific data supporting the materials’ safety. AACs have not been rigorously tested for toxicity, leaching, de-polymerization, or other types of chemical effects that may occur in the presence of food, and thus prevent their broad use in the food industry. AAC applications in sanitary industrial paints and coatings, as well as for clothing, appear to be more near-term possibilities.

Richard Scott, Ph.D. is vice president of research for PolyMedix (Radnor, Pa.) He can be reached at 484-598-2336 or [email protected].