Design of hierarchical surface to inhibit bacterial adhesion and biofilm formation

LEONARDO LIZARRAGA; GASTÓN PARIS; MARÍA ANTONELA COLONNELLA

La Plata

Workshop; Imaging Techniques for Biotechnology and Biomedical Applications; 2016

Adherence of bacteria to abiotic surface and subsequent biofilm formation such as industrial or medical material surfaces is well known but may have undesirable effects. 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% . And in medical settings, biofilms are the cause of persistent infections, triggering immune response, release of harmful toxins and even obstructing indwelling catheters. Besides, they are an important industrial problem that is produced for the biofilms is biocorrosion, or microbially-influenced corrosion which means accelerated deterioration of metals by the presence of biofilms on the metal surface. Due to these reasons, the biofilms formation is an environmental, safety and health risk. Besides, it is an economically important problem in industrial piping principally in petroleum and gas industry . Nature offers multipronged solutions to biofouling. An enormous 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. These facts have encouraged research on a number of bioinspired surface designs [2].The main objective of the present work was to design novel hierarchical bioinspired surface which inhibits 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, as the one showed in the Figure 1, were obtained. 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.It was observed different biofilm evolution in the different wrinkled surface. This fact is indicative the submicro wrinkle topography of the surface has an effect in the bacteria adhesion to the abiotic surface and/or in the biofilm growth.