A novel biofouling control technology for capillary flow cells

Abstract

Prevention of biological fouling is critical to maintenance of optimal function and extended life for equipment and materials deployed in aquatic and marine settings. We established the efficacy of copper plus a proprietary antifouling treatment to prevent biofouling in glass capillary tubes using in situ epifluorescent microscopy and single-photon confocal microscopy to visualize biofilm formation in capillary flow cells exposed to filtered ambient seawater. The capillary cells were subjected to a series of biofouling control treatments with filtered seawater flowing at a rate of approximately 1 mL per minute. A screening study addressed three potential biofouling control concepts for application to development of the Submersible FlowCAM®, a new in situ instrument that can identify and enumerate both phytoplankton and small zooplankton species. The second addressed the effective exposure under a similar flow system using single-photon confocal microscopy as an end-point analysis. Control cells appropriate to each test were included. The first study demonstrated that biofouling in the control cells (no protection) was sufficient to stop flow after 60 days. Flow cells tested with only copper showed bacterial accumulation at 28 and 49 days. In contrast, very little (and in some cases, no) bacterial biofilm accumulation was observed in any of the proprietary or proprietary plus copper treatments throughout the entire 63 day test period. The second test demonstrated that the Cu plus proprietary treatment was highly effective at preventing biofilm formation in capillary flow cells across a range of treatment exposures under a constant copper concentration in the seawater. Copper treatment alone was not sufficient to prevent biofilm formation.