Nanoparticles represent an emerging environmental concern.
Nanoparticles are extremely small particles; even when compared to
bacteria. Since they are engineered in highly-specific manners,
their degradation and environmental effects remain largely
uncertain. Bacteria occupy the base of the food web, and are often
the first biological system to interact with small particles,
colloids and dissolved compounds that enter natural systems.
The bacterial biofilm represents a critical environmental
platform for understanding the capture, concentration, and
transformation of nanoparticles in natural environments. Capture of
nanoparticles by biofilms will influence their subsequent
incorporation into food webs (and ultimately to humans).
The goal of our initial studies is to determine: (1) Do biofilms
‘trap and bioconcentrate” nanoparticles? The biofilm is a ‘sorptive
sponge’ for particles, colloids, and dissolved compounds. It follows
that biofilms will also efficiently concentrate nanoparticles. At
the nano-scale, specific physical/chemical properties will strongly
contribute to the ability of a nanoparticle to become bound or
trapped by the biofilm EPS matrix. We anticipate that sorption of
nanoparticles will also vary over microspatial (i.e. micrometer)
scales. We are examining the specific binding nature of nanoparticle
associations with the EPS matrix molecules using Raman /confocal
microscopy.
A second goal of our initial studies is to determine: (2) Do
biofilm processes transform or degrade nanoparticles? Natural
microbial communities possess a large reservoir and an incredible
genetic potential to degrade relatively refractory compounds. Thus,
certain bacteria may have the ability to up-regulate key genetic
systems to degrade such potentially refractory and toxic compounds. |
