Effect of zinc oxide film morphologies on the formation of Shewanella putrefaciens biofilm

Abstract

Zinc oxide (ZnO) films were prepared on aluminum substrate by a hydrothermal method to investigate the effect of their surface characteristics, including morphology and hydrophobicity, on the corresponding antibiofilm performance. The surface characteristics of the prepared ZnO films were examined by a comprehensive range of methodologies, suggesting that films of distinctive surface morphologies were successfully formed. Subsequently, their antibiofilm activities, using Shewanella putrefaciens as a model bacterium, were assessed. Surface measurements confirmed that the ZnO films equipped with a nanoscopic needlelike surface feature are more hydrophobic than those possessing densely packed microflakes. The reduced number of live cells and presence of biofilm, confirmed by optical and electron microscopy results, suggest that the former films possess an excellent antibiofilm performance. It is believed that the engineered nanoscopic needle feature might penetrate the cell membrane when they are in contact, allowing the effective substance of ZnO antibacterial ingredients to diffuse into the embedded bacteria. Furthermore, such surface characteristics might perturb the integrity of the cell membrane causing the intracellular substance is leaked from the cells. As such, the combinatorial effects of nanoscopic feature resulted in an inhibited growth of S. putrefaciens biofilm on ZnO film.

Preparation and Antibiofilm Properties of Zinc Oxide/Porous Anodic Alumina Composite Films

“…Meanwhile, more biofilm adhesive materials nourish the biofilm bacteria, and the biofilm bacteria multiply rapidly. Consistent with our research, the biofilm adherence is inhibited by the higher hydrophobicity of ZnO film in the initial stage of the biofilm formation [ 49 ]. The adherence of biofilms is affected by the hydrophobic and hydrophilic properties of the materials [ 14 , 53 , 54 ].…”

“…Chi et al [ 47 ] reported that anodized aluminum has no antibacterial activity to Gram-negative bacteria( Escherichia coli and P. aeruginosa ) and Gram-positive bacteria ( Streptococcus faecalis and Staphylococcus aureus ). However, ZnO has an excellent antibacterial and antibiofilm activity [ 25 – 27 ], and there is a positive correlation between antibacterial and antibiofilm activity [ 48 , 49 ]. Furthermore, the antibacterial properties of ZnO are affected by its microstructure [ 50 , 51 ].…”

Growth Inhibition of Gram-Positive and Gram-Negative Bacteria by Zinc Oxide Hedgehog Particles

“…15 The same sharp nanorods with tip diameters of less than 10 nm exerted considerable pressure (up to 10 MPa) on the outer cell wall of bacteria when continuously mixed in solution. 16 Elsewhere, ZnO films composed of nanoscopic needles exhibited greater potential to inhibit bacteria biofilm formation compared to micron-length flakes, 17 and the surface broadness and protrusion of petals in flower-like formations were considered responsible for the differences observed in the antibacterial effect of ZnO structures. 18 ZnO nanoparticles composed of many individual nanosized needle clusters have been synthesized via the hydrothermal growth technique that have a typical crystal wurtzite structure and high purity.…”

Tuning Microbial Activity via Programmatic Alteration of Cell/Substrate Interfaces

“…Column 2 comments on the type of the surface that was created. For example, the materials are commonly used in the form of thin films [98,99,[129][130][131][132][133]100,103,104,[124][125][126][127][128] nanopatterned fiber, [134][135][136] nanopowder, [137,138] or nanorod [139,140] coatings on various test substrates (i.e., glass, steel, and specific polymers).…”

“…At the same time, in certain cases the summary was broader, and a wide set of biointerface or microorganism characteristics were obtained. [98,[109][110][111]124,150,151] The most common inorganic materials used in biointerfacial structures are metal oxides such as ZnO, [95,98,139,140,99,101,[124][125][126][127]133,134] TiO 2 . [100,102,[136][137][138][141][142][143][144][145][146]103,104,[128][129][130][131][132]135] These materials have been demonstrated as effective antibacterial coatings.…”