Early stage anti-bioadhesion behavior of superhydrophobic soot based coatings towards Pseudomonas putida

Biofilm development, associated with the adherence of microbial cells on various solid substrates, has an adverse economic impact and is the main reason for the spreading of microbial infections. The present article reports novel findings about the anti-bioadhesion performance of four types of superhydrophobic soot coatings, deposited via combustion flame synthesis and further functionalized using plasma polymerization and/or fluorination, towards a Gram-negative bacterial strain Pseudomonas putida. The real-time sensor response of four representative soot coated 5 MHz quartz crystal microbalances, along with scanning electron microscopy, fluorescence microscopy and contact angle measurements on the model soot surfaces, reveal reversible and irreversible bioadhesion on the soot during the first hour of cell colonization. Each adhesion mode is related to the presence and distribution of morphological features within the size of bacteria, but the prolonged 7-day exposure to the bacterial suspensions unifies the number of attached cells (only 3 times difference from coating-to-coating). Nevertheless, the soot coatings inhibit the proliferation of Pseudomonas species and reduce their quantity by two orders of magnitude compared to an uncoated glass slide, which demonstrates the importance of surface characteristics for precise control of the initial cell attachment and development of multifunctional soot coatings with anti-bioadhesion properties. (C) 2018 Elsevier Ltd.