OpenQCM

Description

Instruments OpenQCM and OpenQCM Q-1 (Novaetech) enable the detection of mass variation by measuring the change in frequency of a quartz crystal resonator. When an alternating current is applied to two golden electrodes, the crystal starts to resonate. When molecules bind to the surface, the thickness of the crystal changes and this translates into a drop in frequency. The device can be used for example to study molecular interactions between proteins and other molecules such as proteins or DNA and also living cells. One of the partners has to be immobilised to the golden electrode. Unpurified samples can be used for analysis.

Specifications

 

Measurements mass variation(∆m)
Defaulty frequency 10 MHz
Electrode material and diameter gold, 13.9 mm
Nominal sensitivity up to 4.42x10-9 g Hz-1cm-1
Recommended flow rate 0-100 μl/min
Test cell volume 40 μl
Temperature environmental (is logged)
Using multiple device simultaneously yes (2 available)
Immobilization is needed
Analysis of complex samples yes
Portable device yes
Computer connection microUSB
Open software and open hardware yes
Programming language

Java

Sample requirements

Purity/quality of the sample needed

Purity of the ligand (molecule attached to the sensor chip) should be as high as possible, to prevent unspecific binding. In case of Self-Assembled Monolayer (SAM) the feasibility has to be discussed in advance.

Purity and homogeneity of analytes can vary. Sample can be complex (mixtures of proteins, isolates etc.) or purified.

Amount needed for a typical measurement

Volume of the measuring cell is about 30 µl. If measuring in static state, around 100 µl is needed to exchange the liquid inside the cell. For surface functionalization with the ligand, one usually uses protein concentration around 1 mg/ml. Analyte concentration can be much lower, e.g. around 0.1 mg/ml. Molecular weight of the analyte is important since the sensor detects the changes of mass on the surface.

Buffer considerations

Viscosity can affect the measurements a lot since viscous liquids directly interfere with the QCM sensor. If possible viscous buffers should be avoided. Buffers and samples should withstand degassing by vacuum.

Other requirements

Guest researchers are kindly asked to fill in the Sample request form regarding sample quality, experimental conditions and plausible previous results.

Buffers and consumables for experiments can be provided by the National Institute of Chemistry by prior arrangement.

Additional information can be found at http://www.molekulske-interakcije.si/en/equipment/9/openqcm.

Contact

Matic Kisovec

matic.kisovec@ki.si

Kemijski institut

Hajdrihova ulica 19, 1000 Ljubljana

Documents