Title: Design of a dynamic biofilm imaging cell for white-light interferometric microscopy

Abstract

In microbiology research there is a strong need for next generation imaging and sensing instrumentation that will enable minimally invasive and label-free investigation of soft, hydrated structures such as in bacterial biofilms. White light interferometry (WLI) can provide high resolution images of surface topology without the use of fluorescent labels but is not typically used to image biofilms because there is insufficient refractive index contrast to induce reflection from the biofilm’s interface. The soft structure and water-like bulk properties of hydrated biofilms make them difficult to characterize in situ, especially in a non-destructive manner. In this report, we build on our prior description of static biofilm imaging and describe the design of a dynamic imaging flow cell that enables monitoring the thickness and topology of live biofilms over time using a WLI microscope. The microfluidic system is specifically designed to create a reflective interface on the surface of biofilms while minimizing disruption of fragile structures. The imaging cell was also designed to accommodate limitations imposed by the depth of focus of the microscope’s objective lens. Example images of live biofilm samples are shown in order to illustrate the ability of the flow cell and WLI instrument to 1) support bacterialmore » growth and biofilm development, 2) image biofilm structure that reflects growth in flow conditions, and 3) monitor biofilm development over time non-destructively. In future work, the apparatus described here will enable surface metrology measurements (roughness, surface area, etc.) of biofilms and may be used to observe changes in biofilm structure in response to changes in environmental conditions (e.g., flow velocity, availability of nutrients, and presence of biocides). Furthermore, this development will open new opportunities for the use of WLI in bioimaging.« less

Authors:

Larimer, Curtis ^[1]; Brann, Michelle ^[1]; Suter, Jonathan D. ^[1]; Addleman, Raymond Shane ^[1]

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+ Show Author Affiliations

1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

Publication Date:

Wed May 10 00:00:00 EDT 2017

Research Org.:

Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)

Sponsoring Org.:

USDOE

OSTI Identifier:

1358486

Report Number(s):

PNNL-SA-123163
Journal ID: ISSN 0091-3286

Grant/Contract Number:  

AC05-76RL01830

Resource Type:

Accepted Manuscript

Journal Name:

Optical Engineering

Additional Journal Information:

Journal Volume: 56; Journal Issue: 11; Journal ID: ISSN 0091-3286

Publisher:

SPIE

Country of Publication:

United States

Language:

English

Subject:

59 BASIC BIOLOGICAL SCIENCES; 47 OTHER INSTRUMENTATION; white light interferometry; biofilm; bacteria; non-destructive; imaging; flow cell; roughness