A silicon-based extracellular matrix for understanding three-dimensional dynamics in biofilms
Abstract
The proposed research will exploit advances in flexible nanoelectronics and biotechnology to study the dynamics of 3-dimensional Vibrio cholera (Gram-negative) and Bacillus subtilis (Gram-positive) biofilms, two organisms that spend much of their life cycle outside of the human host in aquatic environments. Specifically, a nanoscopic, flexible, three-dimensional, extracellular matrix-like network with distributed electrical potential sensors, strain sensors, electrical stimulators, and photothermal stimulators will be developed and used as a matrix for bacterial biofilm cultures. As the three dimensional biofilms evolve from their founder cells, time-lapse electrical potential and mechanical strain sensing will be conducted throughout the biofilm microenvironment. Electrical and mechanical recordings will be compared (1) for devices that are close to the periphery or the center of a growing biofilm; (2) for devices that are at the upper or basal regions of biofilms; (3) when cells are isolated, or forming communities with neighboring cells; (4) when cells are at different metabolic stages; and (5) when external effectors (e.g. temperature variation, addition of chemicals such as glutamate, variation of ion concentration) are introduced. Next, localized and 3-dimensional electrical and photothermal stimulation will be used to alter signal flow in biofilm cultures, and simultaneous optical imaging and electrical sensing will be performed to evaluate the effect. Additionally, the distribution of key extracellular matrix proteins (e.g. RbmA, RbmC, and Bap1 in Vibrio cholerae) will be imaged and analyzed to understand biofilm stability and architecture through their altered locations in the matrix and their interactions with each other. Moreover, the effect of stimulations on the major biofilm regulators (e.g. VpsR, VpsT, HapR in Vibrio cholerae) that control the expression of structural and regulatory genes will be quantified. The information gained from these stimulation studies is expected to help develop new methods to efficiently destruct biofilms with electrical and optical signals. As a control, before the sensing and stimulation studies are conducted with the silicon-innervated biofilms, the levels of cytotoxicity of the materials will be assessed, the influence of the devices on biofilm formation and extracellular matrix protein expression will be assessed, and the characteristics of the junctions between the bacterial cells and the silicon will be determined. The proposed project defines a new paradigm in biofilm research by integrating microorganisms with flexible nanoscale electronics and other devices. A similar approach has only been applied in engineered tissue systems (engineered cardiac patch, engineered neural tissue, and engineered vascular constructs) and was conducted by this Principal Investigator in 2012 (Tian BZ, et al., Nature Materials 11, 986-994.). The research, if successful, is expected to contribute to a better understanding of the chemical, mechanical, and electrical interplays within biofilms; and has the potential of destructing biofilms cheaply and easily. Additionally, the effort, if successful, would provide a tool to study microbiomes and allow quantitative measurements of microbiome activities at the nano-, macro- and meso-scale. All of these potential impacts are relevant to focus areas within ONR 342.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 23, 2016
- Source ID
- N000141612530
Entities
People
- Bozhi Tian
Organizations
- Office of Naval Research
- United States Navy
- University of Chicago