Title: 0344 - On-Demand Removal of Oral Biofilms via Photoresponsive Coatings


Devatha Nair (Presenter)



Objectives: With approximately 200 million dental restorations performed every year in the U.S., restorative surfaces provide non-native substrates that encourage biofilm growth, along with the pathological ability to increase the risk of developing diseases. We hypothesize that the rapid, transient response of a micron-scale photoresponsive azobenzene coating indcued via the photofluidization effect can be utilized to repeatedly enable oral biofilm removal. The overall aim is to develop and evaluate photoresponsive azopolymer-coatings for composite restoratives.

Methods: Mechanical disruption of biofilms in a bioreactor model via photoinduced changes on the surface of a glassy dental material were evaluated on a photoresponsive, acrylated azobenzene coating on a glassy dental resin. The polymer properties were characterized on a dynamic mechanical analyzer (DMA-TA Q800) and the synthesized azopolymer was characterized using GPC and 1H NMR. P. aeruginosa biofilms (30µm thickness) grown on the surface of the sample was exposed to a dental lamp (430-490 nm) for 45s at 700 mW/cm2 and gently washed in PBS. The films were imaged on a Confocal Laser Scanning Microscope (CLSM-Nikon, Eclipse-Ti inverted microscope) at 10x magnification. The bacteria ejected from the azopolymer coating were quantified by determining the colony forming units per milliliter (CFU/ml) via serial dilutions performed after PBS wash (n=3).Cytotoxicity tests on L929 mouse fibroblast cells were perfomed in accordance with ISO standards (ISO 10993-5, 1999).

Results: An acrylated azopolymer was successfully synthsized (Mw = 225g/mol) and azopolymer-coated glassy polymer films were generated (Tg = 105 ○C) . Cytotoxicity tests on L929 mouse fibroblast cells demonstrated that the material was not cytotoxi.Imaging and quantification of bacteria ejected from the azopolymer coating showed that 100% biofilm removal was achieved from the surface of the azopolymer.

Conclusions: The transient, oscillatory motion induced in azobenzene coatings on the surface of a glassy restorative material can be successfully utilized to disrupt biofilms.Azopolymers represent ideal candidates as smart dental restorative coatings that can be optimized to repeatedly achieve up to 100% removal of biofilms via the photofluidization effect.


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Disclosure Statement:
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: NONE