Development of a quantitative cytotoxicity assay using mouse lymphoma TK cells

Area of Science:

• Biomedical Engineering
• Toxicology
• Cell Biology

Background:

• Traditional cytotoxicity assays for medical devices, like the colony formation assay (CFA), can be inefficient and susceptible to mechanical damage.
• Assessing the safety of medical devices requires reliable and sensitive methods to detect cytotoxic effects on cells.

Purpose of the Study:

• To introduce and validate a new quantitative, automated cytotoxicity assay using mouse lymphoma L5178Y thymidine kinase+/- (TK) suspension cells.
• To compare the sensitivity and efficiency of this new TK cell assay with the conventional CFA for medical device safety assessment.

Main Methods:

• Mouse lymphoma L5178Y TK+/- suspension cells were used in a 72-hour assay in 24-well plates.
• Cells were seeded on six types of contact lenses, and cell growth rate was determined using the Vi-Cell XR automated cell counter.
• Results were compared to the traditional colony formation assay (CFA) using adherent V79-4 cells.

Main Results:

• The TK suspension cell assay demonstrated equivalent sensitivity and greater efficiency compared to the CFA.
• Five of six contact lenses yielded consistent results between both methods.
• One contact lens showed a significant difference, with the TK assay revealing a more pronounced cytotoxic effect (17% cell growth) than the CFA (79% colony formation).

Conclusions:

• The mouse lymphoma TK suspension cell assay is a valuable, quantitative, and automated tool for medical device cytotoxicity evaluation.
• This method is not susceptible to mechanical damage and does not rely on cell adherence, offering distinct advantages over CFA.
• The TK assay provides a reliable alternative for assessing medical device safety, accurately reflecting cytotoxic effects through direct cell number measurement.