Experimental and numerical investigations of implant infection-associated bacterial biofilms in dynamic bioreactor systems

[no abstract

Sketch of the flow chamber and flow chamber system.

<p>A) Assembly drawing with test specimen; B) General setup of the closed circuit system. The red arrows indicate the direction of the flow.</p

Development of a flow chamber system for the reproducible <i>in vitro</i> analysis of biofilm formation on implant materials

<div><p>Since the introduction of modern dental implants in the 1980s, the number of inserted implants has steadily increased. Implant systems have become more sophisticated and have enormously enhanced patients’ quality of life. Although there has been tremendous development in implant materials and clinical methods, bacterial infections are still one of the major causes of implant failure. These infections involve the formation of sessile microbial communities, called biofilms. Biofilms possess unique physical and biochemical properties and are hard to treat conventionally. There is a great demand for innovative methods to functionalize surfaces antibacterially, which could be used as the basis of new implant technologies. Present, there are few test systems to evaluate bacterial growth on these surfaces under physiological flow conditions. We developed a flow chamber model optimized for the assessment of dental implant materials. As a result it could be shown that biofilms of the five important oral bacteria <i>Streptococcus gordonii</i>, <i>Streptococcus oralis</i>, <i>Streptococcus salivarius</i>, <i>Porphyromonas gingivalis</i>, and <i>Aggregatibacter actinomycetemcomitans</i>, can be reproducibly formed on the surface of titanium, a frequent implant material. This system can be run automatically in combination with an appropriate microscopic device and is a promising approach for testing the antibacterial effect of innovative dental materials.</p></div

3D reconstruction of biofilms in side view.

<p>The cells were stained live/dead and analysed by CLSM. Vital cells are depicted in yellow, viable cells in blue. <b>A)</b> <i>S</i>. <i>gordonii</i>, <b>B)</b> <i>S</i>. <i>oralis</i>, <b>C)</b> <i>S</i>. <i>salivarius</i>, <b>D)</b> <i>P</i>. <i>gingivalis</i>, and <b>E)</b> <i>A</i>. <i>actinomycetemcomitans</i>.</p

Biofilm heights on titanium substrata in the flow chamber system.

<p>In each diagram, the mean biofilm heights for five independent experiments are shown. <b>A</b> = <i>S</i>. <i>gordonii</i>, <b><i>B</i></b> = <i>S</i>. <i>oralis</i>, <b>C</b> = <i>S</i>. <i>salivarius</i>, <b>D</b> = <i>P</i>. <i>gingivalis</i>, and <b>E</b> = <i>A</i>. <i>actinomycetemcomitans</i>.</p