Real‐time imaging of anti‐biofilm effects using CP‐OCT

The objective of this study was to develop a method to reliably and reproducibly assess the physical properties of in vitro multi‐species plaque derived biofilms. A custom flow cell (FC) was designed to model oral cavity shear stresses on biofilms grown on hydroxyapatite (HA) discs. A finite‐element program (ANSYS 13) modeled flow velocities and wall shear stresses on the interior 3D dimensions. For the experiment, 1% chlorhexidine (CHX), 5 M urea, and a 1× phosphate‐buffered saline (PBS) were flown through the FC simulating oral rinsing. Near infrared cross‐polarization optical coherence tomography (CP‐OCT) non‐destructively imaged the fluid immersed biofilms in real time (20 frames/s). During low flow, the swell of the biofilm caused from 5 M urea was quite pronounced increase in vertical dimension. Biofilms exposed to 1% CHX showed a slight collapse in the vertical dimension of the biofilm during low flow. During high flow/high sheer stress, the 5 M urea solution effectively removed the biofilm, while both 1% CHX and 1× PBS did not remove biofilms even under high velocity/shear stress conditions. Biotechnol. Bioeng. 2016;113: 198–205. © 2015 Wiley Periodicals, Inc.