Your question is very important, not just to this cell or cell line, but to all cellular physiology of all cell types. How will we measure the impairment of toxins on cell function? Any soft metal, contaminant, toxin, even radiation? What tool and scale will we use to determine these values of toxicity, if not by impairment to cell function? How will the comparisons be made? In a recent fluoride review, these questions are posed. It is time to begin to quantify the damage of these poisonous vectors. Your work is critical to this process. Best wishes to you.
Commonly, researchers will do much characterization and testing in cell lines, and then test primary cell cultures to see if results are similar. Sometimes they are not. Cell lines can be quite different cells from primary cells. Cell lines are easier and usually cheaper to work with, so you can run tests and experiments on them first. Then, depending on those results, you might choose only a subset of those tests to run in primary cell cultures. So when you get to the point of using primary cell cultures, you have a good idea of what you might want to look for based on the experiments in cell lines. You can think of it as primary cell culture results can confirm results in cell lines if the results match. If working only with cell lines, the question may arise as to whether those results are relevant in vivo.
I began my career in tissue culture and I loved growing cells. I believe that there is a way to accomplish the goals you are setting forth for this area of critical research. It involves microscopy, but using different wavelengths of light. It is possible to measure mitochondrial impairment to toxicity with this new method or tool of inquiry. I just have to build it first. In a similar manner to Dr. Raymond Rife's microscope that allowed him to see the cancer factor. As an independent researcher, I am free to share this work with all who are interested. Feel free to contact me. I am suggesting that this tool be built for exactly the purpose that you intend. Joy and peace to all.