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
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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. |
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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. |
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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. |
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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. |