TissueRuptor

Yes, the stainless steel probe can be autoclaved.

Yield and integrity of genomic DNA depend on the disruption and homogenization method used with the Allprep DNA/RNA Kits.

Homogenization with the TissueRuptor (or other rotor–stator homogenizer, such as the Polytron) or the TissueLyser results in greater DNA fragmentation (depending on homogenization time and intensity). However, shorter DNA fragments are easier to elute, so DNA yields will be higher.

In contast, homogenization using the QIAshredder (or a syringe and needle) is more gentle, resulting in less DNA fragmentation. However, longer DNA fragments are more difficult to elute, so DNA yields may be lower.

Efficient DNA isolation requires thorough sample disruption and digestion.

Although the QIAamp and DNeasy procedures requires no mechanical disruption of the tissue sample, the lysis time will be reduced if the sample is ground in liquid nitrogen or mechanically homogenized in advance. For mechanical homogenization, a rotor–stator homogenizer, such as the QIAGEN TissueRuptor, or a bead mill, such as the QIAGEN TissueLyser, can be used.

To improve digestion of tough tissue samples, Proteinase K incubation at 56°C can be performed overnight. DNA yields may be improved by increasing the amount of Proteinase K or by adding additional proteinase K after several hours of digestion.  

We recommend using either the TissueRuptor or the TissueLyser for homogenization of tissues stored in Allprotect Tissue Reagent.

Since tissues incubated in Allprotect Tissue Reagent are harder than fresh tissues, longer homogenization times might be necessary (for details, see the Allprotect Tissue Reagent Handbook).

Furthermore, we do not recommend using rotor–stator homogenizers with a metal probe (e.g., Polytron) if proteins will be purified subsequently, as the metal probe can heat the sample.