Laser Interferometry Analysis of Ciprofloxacin Diffusion through
Pseudomonas aeruginosa Biofilm

In this study the novel application of laser interferometry method in quantitative analysis of drugs distributions in bacterial biofilms is presented. Ciprofloxacin diffusion through P. aeruginosa PAO1 biofilm was used as a model system. It was determined that 0.759 μmol (25.32%) of ciprofloxacin was transported through biofilm after 2400 s from initial amount of 3 μmol. Additionally, laser interferometry method was used to calculate the amount (mol) of drug accumulated in the biofilm formed on nucleopore membrane. We observed that the amount of ciprofloxacin into biofilm is 0.366 μmol (12.2%) after 2400 s. These results were in accordance with measurements obtained by standard cultivation methods. In conclusion, laser interferometry technique might be useful tool in real time calculation of drug concentration in bacterial biofilm as well as its transport through that structure. From clinical point of view, this important information might be used in modeling of antibiotics distribution in correlation with their biological effects on bacterial biofilms.