A Multi-scale Biophysical Approach to Develop Structure-Property Relationships in Oral Biofilms

J. Pattem, M. Davrandi, S. Aguayo, E. Allan, D. Spratt, L. Bozec

Nature

The aim of this investigation was to determine if Optical Coherence Tomography (OCT) and Atomic Force Microscopy (AFM) could be used as a multiscale approach to develop structure-property relationships in oral biofilms, in-vitro. 

The physical and structural properties of oral biofilms change dramatically as they grow. To date, scientists have struggled to quantify the physical and structural properties of such biofilm at any given time during their growth. 

We combined both OCT and AFM to understand which role does the sucrose concentration (low and high sucrose) and age (3 and 5 days) play in the morphological and mechanical properties of oral, microcosm biofilms in-vitro. 

All the biofilms were grown from human pooled human saliva using in-house protocols. The AFM enabled the characterisation of the mechanical properties of the biofilms through Force-Volume Imaging where the OCT was used to evaluate the cross-sectional properties of the biofilms in order to guide the co-location of the AFM probing.

OCT and AFM were successfully applied and we were able to monitor a significant morphological and mechanical response as a function of biofilm culture conditions.

These techniques and applied methodology can now be used in the future to determine and further existing structure property relationships in biofilm growth, proliferation, and maturation. 

This is the first study of its kind into developing a non-destructive, multi-scale approach and is not restricted to the type of biofilm under investigation, nor the in-vitro physiological conditions in which researchers wish to investigate. 

This approach can be applied to a range of biofilms types such as those found in waste-water treatment systems, bio-reactors, catheters and those found in the oral cavity. Varying physiological conditions can also be applied to reflect specific environments, which include chemical strategies to remove biofilms, even under flow.

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