Characterization of biofilm formed by human-derived nanoparticles.
OBJECTIVE
Microbial biofilm matrix contains polysaccharides and proteins and can require extracellular nucleic acids for initial formation. Experiments were designed to identify infectious pathogens in human aneurysms and to characterize biofilm formed by calcified human arterial-derived nanoparticles.


METHODS
A total of 26 different microbial pathogens were isolated from 48 inflammatory aneurysms. Consistent amounts (0.49 McFarland units) of nanoparticles derived from similar tissue were seeded into 24-well plates and cultured for 21 days in the absence (control) or presence of RNase, tetracycline or gentamicin.


RESULTS
Control biofilm developed within 14 days, as detected by concanavalin A and BacLight Green staining. The formation of biofilm in wells treated with RNase was not different from the control; however, gentamicin partially inhibited and tetracycline completely inhibited biofilm formation. Therefore, nanoparticle biofilm retains some characteristics of conventional bacterial biofilm and requires protein-calcium interactions, although extracellular RNA is not required.


CONCLUSIONS
This model system may also allow study of nanosized vesicles derived from donor tissue, including any microbes present, and could provide a useful tool for in vitro investigation of nanoparticle biofilm formation.
Schwartz
Maria K
MK
Department of Physiology & Biomedical Engineering, College of Medicine, Mayo Clinic, Rochester, MN 55905, USA.
Hunter
Larry W
LW
Huebner
Marianne
M
Lieske
John C
JC
Miller
Virginia M
VM
D000783:Aneurysm / Q000382:microbiology*; D018441:Biofilms / Q000254:growth & development*; D006801:Humans; D066298:In Vitro Techniques; D053758:Nanoparticles / Q000382:microbiology*