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A Millifluidic Bulge Test for Multiscale Properties of Engineered Biofilms


Chittur, Priya K. (2023) A Millifluidic Bulge Test for Multiscale Properties of Engineered Biofilms. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/e1yv-mr74.


Biofilms – communities of bacterial cells associated with their extracellular polymeric matrices – are complex materials whose features span many length scales, ranging from bulk cohesive material properties, to mesoscale structural and compositional heterogeneity, down to the microscopic cellular morphology and cell-cell interaction chemistry.

Here, we demonstrate a tool to study the mechanical properties of biofilms across length scales from the mesoscale (0.2 mm) to the bulk (1 mm) using a simplified model system based on genetically engineered E. coli. Using a custom millifluidic device that suspends a 3 mm dia. biofilm across a support, we impose tunable hydrostatic pressure drops in the Pa-kPa range across the biofilm. The resulting deformation of the film through an aperture is visualized with optical coherence tomography and used to estimate bulk and mesoscale mechanical properties of the film. Our method requires only microliters of material, causes minimal disruption to the film structure, and allows for estimates of both average properties as well as local heterogeneity as a function of cell-cell interaction chemistry and biofilm damage and healing. In the final chapter we introduce other model biofilm systems for their unique optical and mechanical properties.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Engineered living materials
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Chemistry
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Kornfield, Julia A.
Thesis Committee:
  • Tirrell, David A. (chair)
  • Kornfield, Julia A.
  • Ravichandran, Guruswami
  • Okumura, Mitchio
Defense Date:17 August 2022
Funding AgencyGrant Number
Caltech Center for Environmental Microbial Interactions (CEMI)UNSPECIFIED
Record Number:CaltechTHESIS:08282022-230140735
Persistent URL:
Chittur, Priya K.0000-0002-9409-4671
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:15010
Deposited By: Priya Chittur
Deposited On:30 Aug 2022 23:17
Last Modified:29 Nov 2023 16:39

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