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ISO 19090:2018 pdf free

ISO 19090:2018 pdf free.Tissue-engineered medical products – Bioactive ceramics
Including positive and negative controls for the assay signal can be useful for each assay. For example,an appropriate negative control can be to conduct the measurement in the absence of cells. The scaffolds can be placed in dishes without cells, incubated with culture medium, washed, stained, imaged and scored. As an example of an appropriate positive control, the scaffolds can be directly seeded with cells using a pipette, incubated in medium to let the cells adhere (possibly 4 h or 24 h), washed, stained,imaged and scored.
These controls provide assurance that the assay is working effectively and help with interpreting the results. In the case where cells migrate into the test scaffolds, it is important to demonstrate that the negative controls did not score positively for cell migration. This provides evidence that the background staining of the scaffold and the scoring procedure, among other things, are reliable. In the case where there is poor migration into the test scaffolds, it is important to demonstrate that the positive controls scored positively for cells. This provides evidence that cells were viable, the stain was effective, and the scoring procedure was reliable (among other things). Including positive and negative controls in the assay makes it possible to interpret the results and improves confidence in the conclusions.
Annexes A and B show typical results and are useful to understand practical results and procedures as referred in the following procedures.
The cell-contact (bottom) side of the specimen shall be observed with a stereoscopic microscope.
Stereoscopic microphotographs of the bottom side shall be taken. The specimen shall be cut into two pieces using a thin scalpel commonly used for eye surgery. Depending on the flatness of bottom surface of the specimen, stained area might have irregular distribution and shape as shown in Figures A.5 and B.3; therefore, the cutting position shall be determined from the stained specimen interface (bottom) that had been in direct contact with the cell layer; and the incision shall be made along the longest determined length through the darkest stained area of the specimen (Figures3 to 6). ISO 19090 pdf download.

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