Rapid Screening for Biological Safety

Cytotoxicity Testing is an in vitro method used to determine the biological response of mammalian cells to medical device extracts or the materials themselves. According to ISO 10993-5, this is a mandatory requirement for all medical devices, serving as a critical indicator of potential biological hazards.
 

1. Key Objectives

• Preliminary Safety Screening: Identifies the presence of toxic leachable substances before progressing to expensive and time-consuming animal studies.

• Quality Control: Acts as a sensitive tool to monitor consistency across different batches and detect potential process-related contaminants.
   

2. Standard Test Methodologies

Under ISO 10993-5, three primary contact methods are utilized:

• Indirect Contact (Agar/Filter Diffusion): Uses an agar layer or filter to protect cells from physical trauma, ideal for screening materials of varying densities.

• Direct Contact: The test material is placed directly onto the cell monolayer. This is the most sensitive method but requires careful handling to avoid physical cell damage.

• Extract Method (MEM Elution): The device is soaked in a culture medium to create an extract, which is then applied to the cells. This is the gold standard for quantitative analysis.
   

3. Evaluation Criteria: Cell Viability

Quantitative assessment is typically performed using assays like MTT or XTT to measure metabolic activity.

• Acceptance Criteria: A reduction in cell viability by more than 30% (i.e., viability below 70%) is considered a cytotoxic effect. If a device fails this test, a thorough toxicological investigation is required.
  
  
  
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