Molecular imaging of bacterial biofilms—a systematic review

Abstract

The formation of bacterial biofilms in the human body and on medical devices is a serious human health concern. Infections related to bacterial biofilms are often chronic and difficult to treat. Detailed information on biofilm formation and composition over time is essential for a fundamental understanding of the underlying mechanisms of biofilm formation and its response to anti-biofilm therapy. However, information on the chemical composition, structural components of biofilms, and molecular interactions regarding metabolism- and communication pathways within the biofilm, such as uptake of administered drugs or inter-bacteria communication, remains elusive. Imaging these molecules and their distribution in the biofilm increases insight into biofilm development, growth, and response to environmental factors or drugs. This systematic review provides an overview of molecular imaging techniques used for bacterial biofilm imaging. The techniques included mass spectrometry-based techniques, fluorescence-labelling techniques, spectroscopic techniques, nuclear magnetic resonance spectroscopy (NMR), micro-computed tomography (µCT), and several multimodal approaches. Many molecules were imaged, such as proteins, lipids, metabolites, and quorum-sensing (QS) molecules, which are crucial in intercellular communication pathways. Advantages and disadvantages of each technique, including multimodal approaches, to study molecular processes in bacterial biofilms are discussed, and recommendations on which technique best suits specific research aims are provided.

The Exometabolome of Xylella fastidiosa in Contact with Paraburkholderia phytofirmans Supernatant Reveals Changes in Nicotinamide, Amino Acids, Biotin, and Plant Hormones

“…Here, we were limited to metabolites being detected through the LCMS method in a HILIC column. Other coupled MS analyses could complement our findings, e.g., using a c18 column (focused on non-polar and large compounds) or through a surface-based MS technique such as NIMS, which would increase the detected metabolites as seen for other models [71][72][73][74].…”

Analysis of antibiofilm activity gold and silver nanoparticles against uropathogenic Escherichia coli using confocal laser scanning microscopy

“…The optimal concentration for antibiofilm activity of gold and silver nanoparticles against UPEC, determined through CLSM analysis, is 100 ppm. These findings contribute to a deeper understanding of biofilm treatment approaches and failures (Reichhardt & Parsek, 2019;van Hoogstraten et al, 2023).…”

“…Its advantage lies in capturing optical slices from specimens, producing three-dimensional (3D) images with volumetric parameters (X, Y, Z) and temporal data (Gupta et al, 2022). Molecular imaging techniques, such as CLSM, contribute significantly to indepth biofilm analysis, providing insights into composition, structure, cell-cell communication, metabolism, drug response, and reactions to environmental stress (van Hoogstraten et al, 2023).…”

“…Visualization of metabolic pathways aids in assessing drug absorption and efficiency. Common biofilm visualization methods include scanning electron microscopy (SEM) and atomic force microscopy (AFM), while staining techniques like crystal violet and confocal laser scanning microscopy (CLSM) provide detailed three-dimensional images of biofilm structures and bacterial cell viability (van Hoogstraten et al, 2023).…”

Effect of surface treatment and shear flow on biofilm formation over materials employed in space water storage and distribution systems

“…Furthermore, it was observed that after 24 h exposure, the rough surfaces promoted the formation of bigger clusters varying in size and shape, compared to SSEP where single cells were mainly noticed. The distribution of these clusters exhibits a spatial organization enabling bacteria to communicate with each other through molecular mechanisms, i.e., quorum sensing (van Hoogstraten et al, 2023). Microscopic images similar to those for SSEP were captured for smooth glass and polydimethylsiloxane surface (PDMS), when exposed to cultures of P. aeruginosa PAO1 and P. aeruginosa PA-14, respectively (Epstein et al, 2013;Shah et al, 2019).…”