Design of Hierchical Surface to Inhibit Bacteria Adhesion and Biofilm formation

MA COLONNELLA; G PARIS; L LIZARRAGA

La Plata

Workshop; Workshop of Imaging Techniques for Biotechnology and Biomedical Applications; 2016

Adhesion of bacteria to abiotic surfaces and subsequent biofilm formation is a well-known phenomenon that has undesirable effects for industrial or medical material surfaces. Biofilms contaminate a wide variety of infrastructures, such as plumbing, oil refineries, paper mills, heat exchangers, medical implants and building HVAC systems [1]. Marine fouling, which is precipitated by the accumulation of bacterial biofilm on ship hulls followed by progressively larger marine organisms, increases the fuel expenditure of seafaring vessels by up to 40%. In medical settings, biofilms are the cause of persistent infections, triggering of immune response, release of harmful toxins and even obstructing indwelling catheters. Besides, another important industrial problem produced by the biofilms is biocorrosion, or microbially-influenced corrosion which determines accelerated deterioration of metals by the presence of sulfate-reducing bacteria in the biofilms formed on the metal surface. Due to these reasons, the biofilms formation is an environmental, safety and health risk. In addition, it is an economically important problem in industrial piping principally for petroleum and gas industry. Nature offers multiple solutions to biofouling. Am important number of biological surfaces prevent microbial colonization due to their surface topographies, e.g.: the shells of mollusks and crabs and the skin of marine mammals and sharks that have encouraged research in bioinspired surface designs [2].The main objective of the present work is to design hierarchical bioinspired surfaces that inhibit the bacterial adhesion to abiotic surfaces and thus the biofilm formation. In order to inhibit biofilm formation surfaces were produced with nano-micrometric hierarchical topography. The hierarchical surface was designed using surface plasma oxidation of uniaxial stretch of polydimethylsiloxane (PDMS) films. This method has the advantage to allow designing sub-micrometric wrinkle topographic surfaces changing the plasma time exposition [3]. Different topography surfaces were obtained (Figura 1). Each topographic surface has wrinkle which different wavelength (from 500 to 2000 nm) and amplitude (from 80 to 700 nm) parameters.The biofilm formation on this novel hierarchical surface was evaluated through exposing them to an inoculum of a bacterial strain (Pseudomonas fluorescens Pf-5) in conditions to produce biofilm, and the surface were analysed using different microscopy techniques, as: i) Tapping Mode technique in liquid with the AFM, ii) ESEM, iii) cryo-SEM. We observed that the surface topography affects the biofilm formation suggesting that submicro wrinkle topography of the surface has an effect in the bacterial adhesion to the abiotic surface and/or in the biofilm growth.Reference:[1] R.T. Bachmann, R.G.J. Edyvean, Biofilms, 2 (2005) 197-227.[2] C. M. Kirschner and A.B. Brennan, Annu. Rev. Mater. Res, 42. (2012), 211?229.[3] F.A. Bayley, J.L. Liao, P.N. Stavrinou, A. Chiche, J.T. Cabral, Soft Matter 10 (2014) 1155-1166.