Plasma-deposited membranes for controlled release of antibiotic to preventbacterial adhesion and biofilm formation

Bacterial infection on implanted medical devices is a significant clinical problem caused by the adhesion of bacteria to the biomaterial surface follo wed by biofilm formation and recruitment of other cells lines such as blood platelets, leading to potential thrombosis and thromboembolisms. To minimi ze biofilm formation and potential device-based infections, a polyurethane (Biospan) matrix was developed to release, in a controlled manner, an antib iotic (ciprofloxacin(T)) locally at the implant interface. One material set consisted of the polyetherurethane (PEU) base matrix radiofrequency glow d ischarge plasma deposited with triethylene glycol dimethyl ether (triglyme) ; the other set had an additional coating of poly(butyl methyacrylate) (pBM A). Triglyme served as a nonfouling coating, whereas the pBMA served as a c ontrolled porosity release membrane. The pBMA-coated PEU contained and rele ased ciprofloxacin(T) in a controlled manner. The efficacy of the modified PEU polymers against Pseudomonas aeruginosa suspensions was evaluated under flow conditions in a parallel plate flow cell. Bacterial adhesion and colo nization, if any, to the test polymers were examined by direct microscopic image analysis and corroborated with destructive sampling, followed by dire ct cell counting. The rate of initial bacterial cell adhesion to triglyme-c oated PEU was 0.77%, and to the pBMA-coated PEU releasing ciproaoxacin(T) w as 6% of the observed adhesion rates for the control PEU. However, the rate of adherent cell accumulation due to cell growth and replication was appro ximately the same for the triglyme-coated PEU and the PEU controls, but was zero for the pBMA-coated PEU releasing ciprofloxacin(T). (C) 2000 John Wil ey & Sons, Inc.