Biofouling causes serious problems in many kinds of technical equipment. Consequently, there is great interest in developing surfaces with anti-adhesive and antimicrobial properties. Many such surfaces exist in nature, and artificial systems that mimic or are inspired by these natural systems could potentially be valuable technical surfaces. Recent studies on the interactions of bacteria with cicada wings revealed that rather than the wings being effective at repelling bacteria, after attachment the wing surface disrupts bacterial cell walls. Inspired by these structures, SmartMembranes GmbH used electrochemical precision etching to produce porous anodized aluminum oxide (AAO) membranes with structurally well-defined surface nanopatterns having pore diameters of 200-300nm. We investigated the surfaces of these AAO membranes to assess their potential to prevent biofouling, using Escherichia coli as a model microbe. Bacterial adhesion tests were conducted using a modular flow cell system that is designed to enable on-line observation of biofilm formation in continuous flow on opaque surfaces using a fluorescence microscope. The system was adapted to permit testing of multiple samples with various dimensions and material properties simultaneously. Bacterial adhesion tests showed that AAO surfaces with pore diameters of 300nm exhibit 99% less biofilm growth than widely used electropolished stainless steel.