 |
|
Q-SENSE - QCM-D
For rapid characterization of bio-interfaces and
surface processes
Q-Sense manufactures surface science instruments for
real-time, label-free studies of molecular adsorption/interactions on different
substrates. The instruments are based on the patented Quartz Crystal
Microbalance with Dissipation technique (QCM-D), which tracks mass and
structural changes of molecular binding events taking place on the instrument's
sensor surfaces. 
A Q-Sense QCM-D instrument monitors events as they occur
in real-time. It is a valuable tool in understanding molecular changes at the
surface. QCM-D can determine the mass of very thin surface bound layers while
also providing simultaneous data about the layers' viscoelastic properties,
which indicates the structural properties of adsorbed molecular layers. By
revealing structural details and mass at the same time, QCM-D gives researchers
the information they need to assess the impact of surface modification or to
characterise molecular interactions.  
The heart of QCM-D is a sensor, a thin disc of
crystalline quartz sandwiched between two electrodes, the top one being the
sensor surface. Any layer of molecules forming on the surface of the quartz
crystal creates subtle changes to the frequency of oscillation and its
duration.
Q-Sense has a range of instrumentation and software
tools to allow sophisticated interpretation of the sensing data. Q-Sense has
created methods to measure and identify the essential nature of the layer that
has formed, giving information about its mass, thickness and viscoelastic
properties. In addition, kinetics and affinity of reactions may be calculated.
The QCM-D technique is an important tool when
investigating lipids, proteins and polymers in reactions such as adsorption,
hydration, cross-linking and phase-transitions.
Below is an example of the binding of a protein layer
and subsequent structural changes in the layer that are monitored in real time
by using QCM-D.
The differences in the oscillation characteristics of
the sensor are tracked as changes to the surface occur and measured as changes
in resonance frequency and dissipation. A change in frequency means a mass
change on the surface (ng/cm2 sensitivity), simultaneously the dissipation
gives information about the structural (viscoelastic properties) properties of
adsorbing molecular layers; a phase transition or conformational change in
adsorbed molecular layers will change the dissipation of the quartz crystal.
For all applications, Q-Sense QCM-D instruments
enable:
- Mass measurements. Nanogram sensitivity, less
than 1% of a protein monolayer is detectable. .
- Mass measurements. Nanogram sensitivity, less
than 1% of a protein monolayer is detectable.
- Real time, in situ and label free. Study
kinetics, pH dependence etc. using the native molecule.
- Flexible choice of substrate. Metals,
polymers; any material that can be applied as a thin film can be used.
Typical real time measurements include:
- How molecules bind to different surfaces when it
comes to mass and structure of adsorbed layers (adsorption, adhesion);
- How immobilised molecules interact with the next
layer of molecules. (interaction);
- How immobilised thin films change due to changes in
the buffer or when exposed to liquid or solvents (swelling, hydration)
- How immobilised thin films (polymers, metals) are
degraded, dissolved or etched
The Products -
Instruments, Options and Accessories
The E1 and E4 (shown above) are the latest
generation of QCM-D instruments from Q-Sense, designed for flexibility,
ease-of-use and, with the E4, higher throughput measurements. New software and
electronics allow measurement data from each sensor to be acquired within a
second with high sensitivity.
E1 is the single-sensor entry level QCM-D system. The E1
enables accurate and simple QCM-D measurements of real-time processes taking
place on the sensor surface..
The E4 instrument has four removable flow
modules, each holding a sensor. The flow modules can be used in any serial or
parallel configuration with simultaneous measurement of all four sensors.
Q-Sense currently offers five optional modules
for the E1 and E4: a flow module, an electrochemistry module, a humidity
module, an open module and a window module. There is also a broad range of
different substrates (sensors) to choose from.
In addition, there are a number of accessories available
for both instruments, including sensor accessories, pumps, sample heater,
consumables and replacement parts.  
Features of the QCM-D
E1 and E4 Instruments
- Analyze mass, elasticity, viscosity, thickness and
density
- Real time analysis
- 1- or 4- sensors in separate (removable) flow modules
- Controlled one-direction flow
- Flexible choice of surface
- Sensitivity, 0.5 ng/cm2
- Measurement rate, > 100 points/s
- Volume above sensor ~ 40 µL
- Sample volume ~ 300 µL
- Quick, precise temperature control
- High frequency capacity, 70 MHz
- Chemical compatibility
- HPLC fittings
- Optional modules include: electrochemistry, flow
module, humidity module, open module and window module
- Easy cleaning: all parts exposed to liquid can be
removed and immersed in cleaning baths.
For
further information and prices, please click
here.
Please also visit the Q-sense Website for further
information:
|
