Antibacterial nitric oxide-releasing xerogels: Cell viability and parallel plate flow cell adhesion studies

The ability of nitric oxide (NO)-releasing xerogels to reduce adhesion of Pseudomonas aeruginosa under flowing conditions was evaluated using a parallel plate flow chamber. At a controlled bacterial suspension flow rate of 0.2mL/min, the NO-releasing xerogels reduced bacterial adhesion in a flux-dependent fashion, with an NO flux of similar to 21 pmol cm(-2) s(-1) reducing P. aeruginosa adhesion by similar to 65% compared to controls. Fluorescent viability staining indicated that bacteria adhered to NO-releasing xerogels were killed within 7h. Quantitative cell-plating viability studies showed that the extent of bactericidal activity was dependent on the total amount of NO released, with 750 nmol cm(-2) killing > 90% more adhered bacteria than xerogels releasing 25 nmol cm(-2). Thus, NO-releasing xerogels were shown to both inhibit P. aeruginosa adhesion and kill adhered bacteria cells, two important steps toward designing anti-infective biornaterial coatings. (c) 2007 Elsevier Ltd. All rights reserved.