Bacterial behavior on honeycomb patterned surfaces

Abstract

The adhesion of bacteria to medical implants forming biofilms might lead to healthcare-associated infections. Initial bacterial adhesion is mediated by material surface properties. Therefore, control of bacterial adhesion to material surfaces is important for reducing infection. Numerous researches have been devoted to the chemical and physical modification of biomaterial surfaces to control initial bacterial adhesion. However, the successful design of biomaterials for the treatment of infections remains a challenge. Surface topographic patterns of micro- or nano-scale have been effective to manipulate behavior of different types of cells. Previously, the bacterial behavior on the micro-pillar patterned surfaces has been studied in our group and confirmed that the micro-pillar pattern do have effects on the bacterial behavior. Now in this study we further fabricated a honeycomb pattern which provided a reduced continuous surface area compared with micro-pillar pattern. The honeycomb patterns on silicon substrate with characteristic dimensions varied from 0.5 μm to 10 μm were fabricated. Two typical bacteria with distinctive shapes (E.coli and S.aureus) were used as study models. After culturing the samples with bacteria, the effects of honeycomb patterns on the bacterial adhesion, growth, proliferation and viability were investigated. Experimental results show that the honeycomb topography with specific feature size around 1 μm can significantly reduce bacterial adhesion. Furthermore, the honeycomb patterns can inhibit bacterial growth and change the direction of growth when the bacterial is confined into a well. These influences may result from the physical confinement effect on bacteria. By comparing Sample_UP vs. Sample_DOWN, the adherent bacterial is much less on Sample_DOWN, but the trends of bacterial adhesion are the same and irrespective of the gravity of bacteria. In comparison with bacterial responses to pillar patterns, we found that topographic patterns with dimensions approaching to bacterial size can provide stronger physical confinement effect than others. However, the viability of the bacteria does not obviously influenced by the pillar and honeycomb topography within 24h. This study is expected to contribute to better understanding of topographic effects on bacterial behavior and healthcare-associated infections on biomaterials.

Date of Award	2013
Original language	English
Awarding Institution	The Hong Kong University of Science and Technology