Monitoring Aerobic Marine Bacterial Biofilms on Gold Electrode Surfaces and the Influence of Nitric Oxide Attachment Control.

Detection of aerobic marine bacterial biofilms using electrochemical impedance spectroscopy has been done to monitor the interfacial response of Pseudoalteromonas sp. NCIMB 2021 attachment and growth in order to identify characteristic events on a 0.2 mm diameter gold electrode surface. Uniquely, the applicability of surface charge density has been proven to be valuable in determining biofilm attachment and cell enumeration over a 72 h duration on a gold surface within a modified continuous culture flow cell (a controlled low laminar flow regime with Reynolds number ≈ 1). In addition, biofilm dispersal has been evaluated using 500 nM sodium nitroprusside, a nitric oxide donor (nitric oxide is important for the regulation of several diverse biological processes). Ex situ confocal microscopy studies have been performed to confirm biofilm coverage and morphology, plus the determination and quantification of the nitric oxide biofilm dispersal effects. Overall, the capability of the sensor to electrochemically detect the presence of initial bacterial biofilm formation and extent has been established and shown to have potential for real-time biofilm monitoring.

Electrochemical Sensing and Characterization of Aerobic Marine Bacterial Biofilms on Gold Electrode Surfaces.

Reliable and accurate in situ sensors capable of detecting and quantifying troublesome marine biofilms on metallic surfaces are increasingly necessary. A 0.2 mm diameter gold electrochemical sensor was fully characterized using cyclic voltammetry in abiotic and biotic artificial seawater media within a continuous culture flow cell to detect the growth and development of an aerobic Pseudoalteromonas sp. biofilm. Deconvolution of the abiotic and biotic responses enable the constituent extracellular electron transfer and biofilm responses to be resolved. Differentiation of enhanced oxygen reduction kinetics within the aerobic bacterial biofilm is linked to enzyme and redox mediator activities.

Designing biomimetic antifouling surfaces.

Marine biofouling is the accumulation of biological material on underwater surfaces, which has plagued both commercial and naval fleets. Biomimetic approaches may well provide new insights into designing and developing alternative, non-toxic, surface-active antifouling (AF) technologies. In the marine environment, all submerged surfaces are affected by the attachment of fouling organisms, such as bacteria, diatoms, algae and invertebrates, causing increased hydrodynamic drag, resulting in increased fuel consumption, and decreased speed and operational range. There are also additional expenses of dry-docking, together with increased fuel costs and corrosion, which are all important economic factors that demand the prevention of biofouling. Past solutions to AF have generally used toxic paints or coatings that have had a detrimental effect on marine life worldwide. The prohibited use of these antifoulants has led to the search for biologically inspired AF strategies. This review will explore the natural and biomimetic AF surface strategies for marine systems.