Effect of organic conditioning layers adsorbed on stainless steel AISI 304 on the attachment and biofilm formation of electroactive bacteria Shewanella putrefaciens CN32

Abstract

Abtract The initial attachment and subsequent biofilm formation of electroactive bacteria Shewanella putrefaciens CN32 was investigated to clarify the influence of organic conditioning layers. A selection of macromolecules and self‐assembled monolayers (SAMs) of different chain lengths and functional groups were prepared and characterized by means of infrared spectroscopy in terms of their chemistry. Surface energy and Zeta (ζ‐) potential of the conditioning layers was determined with contact angle and streaming current measurements. Among the studied surface parameters, a high polar component and a high ratio of polar‐to‐disperse components of the surface energy has emerged as a successful indicator for the inhibition of the initial settlement of S. putrefaciens on stainless steel AISI 304 surfaces. Considering the negative surface charge of planktonic S. putrefaciens cells, and the strong inhibition of cell attachment by positively charged polyethylenimine (PEI) conditioning layers, our results indicate that electrostatic interactions do play a subordinate role in controlling the attachment of this microorganism on stainless steel AISI 304 surfaces. For the biofilm formation, the organization of the SAMs affected the local distribution of the biofilms. The formation of three‐dimensional and patchy biofilm networks was promoted with increasing disorder of the SAMs.

Keywords

• bacterial attachment
• conditioning films
• self‐assembled monolayers
• stainless steel