Cytotoxicity refers to cell death, lysis and inhibition of cell growth caused by products, materials and extract.
Application of standard
ISO 10993-5, ISO 7405, GB/T 16886.5, GB/T 14233.2, USP Chapter <87>, YY/T 0268, EN ISO 10993-5, YY/T 0127.9, ISO 7405, EN ISO 7405
Test Methods and Principles
MTT method
MTT cytotoxicity test, also known as MTT assay, is a test to detect the survival and growth of cells. The test principle is that succinate dehydrogenase in mitochondria of living cells can reduce exogenous MTT to water-insoluble blue purple crystal Formazan and deposit it in cells, while dead cells do not have this function. Dimethylsulfoxide (DMSO) can dissolve formazan in cells, and evaluated the OD Value was the measurement wavelength at 570 nm by enzyme linked immunoassay, which could indirectly reflect the number of living cells. Within a certain range of cell numbers, the amount of MTT crystallization was proportional to the number of cells.
Agar method
Agar method for leachable materials that can be diffused by agar or agarose. The cultured cells were covered with a piece of nutritionally enriched agar and the test material was placed on the agar layer. The leachable material in the material diffuses into the agar and comes into contact with cells. Reactive dyes can be added after culture to help determine the cytotoxicity of the material, which can be determined if the cell lines around or below the material are malformed, unstained, degenerate, and decompose.
The filter diffusion method
The filter diffusion method is suitable for leachable materials that can be diffused through the filter membrane. A membrane containing cells was placed on agar or agarose medium, and the test article was then placed in close contact with the membrane and cytotoxicity was determined by a suitable staining procedure.
MEM elution method
MEM elution method, which is used to determine the cytotoxicity of the test material extract. The extractions were extracted with different extracts and conditions, and the extractions were transferred to the cell layer. After culture, the cells were observed by microscope to see whether the cells were deformed, degraded or decomposed.
Direct contact method
Direct contact method is suitable for materials with moderate density. The test material is placed directly in the middle of the cell layer, and some of the soluble chemicals will spread into the culture medium and come into direct contact with the cells. A material can be determined to be cytotoxic if its surrounding cell lines deform, degenerate, and decompose.
Period
The test period is shown in Table 1.
Product
Test cycle
Short time contact medical devices
2 weeks, please contact Epin for details
permanent contact medical devices
3 weeks, please contact Epin for details
Note: Short time contact：Non-implantable devices that are in short contact with undamaged skin or mucous membrane.
permanent contact: Devices with a cumulative contact duration greater than 24 h
