Real‐time imaging of anti‐biofilm effects using CP‐OCT. Issue 1 (4th September 2015) - Rasmussen, Karin
ABSTRACT: 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. Abstract : Cross Polarization Optical Coherence Tomography was integrated with a flow cell system to assess the effects of 1% CHX, 5M urea, and 1X PBS on multi‐species biofilms. Comparison on the biofilm removal properties between the three test compounds demonstrated that antimicrobial effects are not correlated to biofilm removal effects. Biofilm swelling and biofilm removal by 5 M urea across a large 5 mm cross sectional surface area was measured directly with CP‐OCT imaging.