Bead Beating: A Primer (continued)
ANIMAL
Elastic Animal
Tissue Homogenization: Skin/Sclera/Cartilage
Animal tissues that contain a significant amount of
collagen such as skin, sclera, and cartilage are very difficult to
homogenize by any method. The pliable and resilient nature of these tissues
is by design. In order to effectively homogenize
these elastic tissues, the mass of the sample needs to be very small
relative to the grinding media and vessel. Samples less than 20 mg are best
processed in a 4 ml polycarbonate vial with one 3/8” stainless steel ball.
Larger samples are best processed in a 15 ml polycarbonate vial with two
7/16” stainless steel grinding balls. It is often necessary to homogenize
elastic tissues cryogenically. In such cases, a GenoGrinder® or
Mini G™ models equipped with Cryoblocks are needed.
Procedures
| 1. |
The
grinding formats available for elastic tissues are limited. Sample size is also limited. Samples need to be dissected into small
pieces (3 x 3 mm) prior to homogenization. Avoid thick,
large pieces of tissue since these will not effectively homogenize. Samples are best processed cryogenically using liquid nitrogen to
chill the sample, tube, ball and Cryoblock. Caps are
usually made of polypropylene and, if too cold, will crack. |
| 2. |
Prepare samples according to the following table: |
|
4 ml Vials |
15 ml Vials |
| Sample Mass |
20 mg |
Up to 250 mg |
| Grinding Balls |
1 x 3/8" |
2 x 7/16” |
| Processing Time |
5 minutes |
5-10 minutes |
| Bead Beater Speed |
High |
High |
| 3. |
Process the samples as stated in the table. Heat is generated during processing, so it is possible that samples
may warm and thaw by the end of processing. |
| 4. |
Sample homogenization can be monitored visually.
Ideally the tissue will be converted into a fine powder.
Samples with large amounts of collagen may not homogenize well. |
| 5. |
Homogenized tissue can be stored frozen or thawed and used. |
Suggested Products
| Balls: |
3/8’’ Stainless Steel (GBSS
375-1000-02), 7/16’’ Stainless Steel (GBSS
437-1000-03) |
| Vial Sets: |
24 Well PC Vial Set (PCVS
04-240-03), 15 ml Polycarbonate Vial Sets (PCVS
15-050-22) |
| Homogenization Vessel: |
See Appendix A |
| Homogenizers: |
Cryogenic grinding requires a GenoGrinder® or Mini G™ (Appendix A) |
| Cryogenic Option: |
Cryoblocks (4 ml and
15 ml) |
