KBC / UCMR Seminar
Adam Olsson
McGill University\, Canada
Title:
'Acous
tic Sensing of Bacterium-Substratum Interfaces'
Room
: KB3B3\, KBC
Host: Madeleine Ramstedt
Abstract:
Acoustic Sensing of Bacterium-Substratum Interfaces
Adam L.J.
Olsson
McGill University
\;
Bacterial adhesion to
surfaces and subsequent biofilm formation is an important phenomenon in ma
ny areas including\, amongst others\, biomedical engineering\, food proces
sing and water treatment. \;Since biofilms essentially originate from
only a few initial bacterial colonizers\, understanding the mechanisms go
verning the initial bacterial adhesion event may help designing surfaces w
ith the ability to manipulate biofilm formation.
This present
ation explores the possibilities to utilize a quartz crystal microbalance
with dissipation monitoring (QCM-D) to acoustically sense the mechanical p
roperties of the bacterium-surface interface. The QCM-D is generally consi
dered a mass balance\, where a negative shift in the resonance frequency o
f a quartz crystal sensor is proportional to attached mass. However\, in t
he case of bacterial adhesion\, the surface attached bacterium possesses a
resonance frequency that couples to the oscillation of the sensor surface
. The resulting frequency shift of this “coupled resonance” is either nega
tive or positive\, depending on the ratio between QCM-D resonance frequenc
y and the bacterium resonance frequency which\, in turn\, is determined by
its mass and surface contact stiffness. Thus\, analyzing bacterial adhesi
on in QCM-D within the context of “coupled resonance” offers a unique oppo
rtunity to monitor mechanical properties of bacterium-surface contacts.
Since the quartz sensor is mounted in a temperature controlled
flow module\, and because change in resonance frequency of the sensor is m
onitored in real time\, it possible to follow dynamic changes of the bacte
rium-surface contact during both the initial adhesion event as well as dur
ing subsequent biofilm growth. Another important aspect of the method is t
hat the stiffness\, which is related to bond strength\, is investigated wi
thout detaching the bacteria from the surface\; hence the method is non-de
structive.
\;
\;
KBC / UCMR Seminar
Ada
m Olsson
McGill University\, Canada
Title:
'Acoustic Sensing of Bacterium-Substratum Interfaces'<
br />
Room: KB3B3\, KBC
Host: Madeleine Ramstedt
Abstract:
Acoustic Sensing of Bacterium-Substratum Interface
s
Adam L.J. Olsson
McGill University
\;
Bacte
rial adhesion to surfaces and subsequent biofilm formation is an important
phenomenon in many areas including\, amongst others\, biomedical engineer
ing\, food processing and water treatment. \;Since biofilms essential
ly originate from only a few initial bacterial colonizers\, understanding
the mechanisms governing the initial bacterial adhesion event may help des
igning surfaces with the ability to manipulate biofilm formation.
This presentation explores the possibilities to utilize a quartz crys
tal microbalance with dissipation monitoring (QCM-D) to acoustically sense
the mechanical properties of the bacterium-surface interface. The QCM-D i
s generally considered a mass balance\, where a negative shift in the reso
nance frequency of a quartz crystal sensor is proportional to attached mas
s. However\, in the case of bacterial adhesion\, the surface attached bact
erium possesses a resonance frequency that couples to the oscillation of t
he sensor surface. The resulting frequency shift of this “coupled resonanc
e” is either negative or positive\, depending on the ratio between QCM-D r
esonance frequency and the bacterium resonance frequency which\, in turn\,
is determined by its mass and surface contact stiffness. Thus\, analyzing
bacterial adhesion in QCM-D within the context of “coupled resonance” off
ers a unique opportunity to monitor mechanical properties of bacterium-sur
face contacts.
Since the quartz sensor is mounted in a temper
ature controlled flow module\, and because change in resonance frequency o
f the sensor is monitored in real time\, it possible to follow dynamic cha
nges of the bacterium-surface contact during both the initial adhesion eve
nt as well as during subsequent biofilm growth. Another important aspect o
f the method is that the stiffness\, which is related to bond strength\, i
s investigated without detaching the bacteria from the surface\; hence the
method is non-destructive.
\;
\;