Monitoring Early Stages of Bacterial Adhesion at Silica Surfaces through Image Analysis

Abstract

Understanding bacterial adhesion and biofilm formations on abiotic surfaces are important biological processes that affect the growth of bacteria, with its far-spreading impacts on in everyday life, either as a benefactor or as an inhibitor. To study these bacterial interactions, tools to probe these interfaces are also important to provide further means for discovery of the adhesion mechanisms. In this thesis, a customized imaging platform was developed, utilizing brightfield microscopy to study E. coli K12 on silica surfaces over the stages of bacteria growth. Results observed bacteria adhering onto silica surfaces in a preferential pattern to already existing bacteria-adhered colonies. This suggest that bacteria, once adhered to the surface, enhance attraction of other planktonic bacteria. The platform was designed to enable concurrent Raman measurements, with further optimization required in order to enhance the Raman signals from individual cells. Results from this study provide strong evidence to link changes in interfacial water structure with previous surface vibrational spectroscopy experiments, where the surface coverage of bacteria was found to reach a maximum earlier in the stages of growth compared to the surface water response, indicating that adhesion alone is not the primary contributing factor to modification of the surface microenvironment.

Light-regulated adsorption and desorption of Chlamydomonas cells at surfaces

“…20 The vast majority of the literature however centers around bacterial surface colonization. [21][22][23][24][25][26][27][28] In contrast, studies of biofilms involving other important exemplars of microbial life, particularly photoactive microalgae, remain rather elusive. Microalgae are a diverse group of eukaryotic, photosynthetic organisms that are considered to be primary producers of oxygen and organic molecules on Earth.…”

Microbial Biofilms: Applications, Clinical Consequences, and Alternative Therapies

“…This indicates the growing commercial interest and also highlights the need for bench-side-to-bedside research in the field of biofilms and the development of anti-biofilm agents [ 25 ]. This growth in biofilm research has been triggered by the advancement and development of several techniques of molecular biology, such as microscopic, spectroscopic, bioinformatics, sequencing, and several other methods, which are summarised in Figure 3 [ 16 , 26 , 27 , 28 , 29 ]. Novel methods such as SAW (surface acoustic waves) and bioimpedance-based sensing are also used [ 30 ].…”

Probing Covalent Interactions at a Silicone Adhesive/Nylon Interface

“…Because of the selection rule of the second-order nonlinear optical SFG process, only a medium without inversion symmetry can generate an SFG signal under the electric dipole approximation, which gives the SFG intrinsic submonolayer interfacial sensitivity and selectivity. − SFG is capable of detecting the presence, coverage, and orientation of functional groups at surfaces and interfaces, including buried solid/solid interfaces in situ. SFG theory and data analysis have been well-developed and extensively reported. − SFG was shown to be effective for investigating buried polymer interfaces, including silicone elastomer/thermoplastic interfaces. ,− However, most of the silicone elastomer interfacial studies have focused on the orientation, alignment, and reactivity of alkoxysilane groups, and none have studied adhesion of silicone elastomers to polyamides, which are widely used as engineering thermoplastics both in textiles and in structural components, because of their excellent strength, toughness, and heat resistance. The semicrystalline nature of common polyamides such as nylon makes them a challenge for developing adhesion.…”