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Novel, environmentally friendly antimicrobial coatings containing tethered biocide moieties derived from the ubiquitous biocide, triclosan, were synthesized and characterized using a high-throughput workflow. Triclosan was first modified with an acrylate functionality and, subsequently, copolymerized with hydroxyethyl acrylate and butyl acrylate using conventional free radical polymerization to form an array of acrylic polyol terpolymers. The polyols were characterized using nuclear magnetic resonance spectroscopy, differential scanning calorimetry, and gel permeation chromatography. Arrays of urethane coatings were produced from the array of acrylic polyol terpolymers and, subsequently, characterized using parallel dynamic mechanical thermal analysis, surface energy measurements, and various biological assays. The results of the biological assays showed that the coatings were effective toward inhibiting Staphylococcus epidermidis biofilm retention without leaching triclosan or other toxic components from the coating. The level of antimicrobial activity was found to increase with the content of triclosan moieties incorporated into the coating matrix. These results indicate that triclosan moieties tethered to a polymer matrix can impart antimicrobial properties via a contact-active, nonleaching (i.e., environmentally friendly) mechanism. Since S. epidermidis is one of the primary microorganisms associated with infection and failure of implanted medical devices, such as prosthetic heart valves, urinary catheters, and a variety of orthopedic implants, these coatings may have good potential for commercialization in some of these applications.

A broad-spectrum antimicrobial drug, levofloxacin, was successfully incorporated into a siloxane coating by covalent attachment. First, an epoxy-functional poly(dimethylsiloxane) (Ep-PDMS) was synthesized by platinum-catalyzed hydrosilylation using poly(methylhydro-co-dimethyl)siloxane and allyl glycidyl ether. Next, levofloxacin was reacted with Ep-PDMS using a stoichiometric excess of epoxy groups relative to levofloxacin to produce a siloxane copolymer containing both pendant levofloxacin and epoxy moieties (levo-Ep-PDMS). Since attachment (i.e. tethering) of levofloxacin occurred via ring-opening of epoxy groups by the carboxylic acid group of levofloxacin, the tether produced was an ester-functional tether. Crosslinked surface coatings were produced by solution blending the polymer with diethylenetriamine as a crosslinker. Compared to a control coating produced by simply blending levofloxacin into a polysiloxane, the coating containing tethered levofloxacin moieties displayed a uniform distribution of levofloxacin, higher initial kill, and sustained antimicrobial surface activity.

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