Transport of nanoparticles and tobramycin-loaded liposomes in Burkholderia cepacia complex biofilms

PLoS One. 2013 Nov 14;8(11):e79220. doi: 10.1371/journal.pone.0079220. eCollection 2013.

Abstract

Due to the intrinsic resistance of Burkholderia cepacia complex (Bcc) to many antibiotics and the production of a broad range of virulence factors, lung infections by these bacteria, primarily occurring in cystic fibrosis (CF) patients, are very difficult to treat. In addition, the ability of Bcc organisms to form biofilms contributes to their persistence in the CF lung. As Bcc infections are associated with poor clinical outcome, there is an urgent need for new effective therapies to treat these infections. In the present study, we investigated whether liposomal tobramycin displayed an increased anti-biofilm effect against Bcc bacteria compared to free tobramycin. Single particle tracking (SPT) was used to study the transport of positively and negatively charged nanospheres in Bcc biofilms as a model for the transport of liposomes. Negatively charged nanospheres became immobilized in close proximity of biofilm cell clusters, while positively charged nanospheres interacted with fiber-like structures, probably eDNA. Based on these data, encapsulation of tobramycin in negatively charged liposomes appeared promising for targeted drug delivery. However, the anti-biofilm effect of tobramycin encapsulated into neutral or anionic liposomes did not increase compared to that of free tobramycin. Probably, the fusion of the anionic liposomes with the negatively charged bacterial surface of Bcc bacteria was limited by electrostatic repulsive forces. The lack of a substantial anti-biofilm effect of tobramycin encapsulated in neutral liposomes could be further investigated by increasing the liposomal tobramycin concentration. However, this was hampered by the low encapsulation efficiency of tobramycin in these liposomes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents* / pharmacokinetics
  • Anti-Bacterial Agents* / pharmacology
  • Biofilms / drug effects*
  • Biological Transport / drug effects
  • Burkholderia cepacia / physiology*
  • Drug Delivery Systems*
  • Liposomes / pharmacokinetics
  • Liposomes / pharmacology
  • Nanoparticles*
  • Tobramycin* / pharmacokinetics
  • Tobramycin* / pharmacology

Substances

  • Anti-Bacterial Agents
  • Liposomes
  • Tobramycin

Grants and funding

This research has been funded by the Interuniversity Attraction Poles Programme initiated by the Belgian Science Policy Office and by a concerted action grant by Ghent University. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.