A scaffold material that supports the growth of cells within a three dimensional environment can be used to develop in-vitro tests that better mimic the behavior of human cells, according to the research published in Small.
2D does not represent real life tissue
The scientists, led by Professor Kotov at the University of Michigan, argued that common 2D cell cultures do not adequately represent the functions of 3D tissues.
The extensive cell – cell, and cell – intercellular matrix interactions are not reflected in the 2D models, nor are the transport and diffusion conditions, the scientists explained.
For this reason toxicity tests using 2D models may not come up with the same results as in vivo tests.
Indeed, the researchers note that previous research has found cytotoxic effects of carbon nanotubes, magnetic nanoparticles, quantum dots and fullerenes, whereas animal models found no adverse effects.
The 3D toxicity testing system developed by the Michigan scientists mimics human cells and tissues but in a test tube.
“This allows for conducting a variety of tests that were hitherto not possible or were restricted due to a lack of availability of tissue samples or regulatory challenges around animal testing,” explained Mr Mahendra Ramsinghani from the University of Michigan Technology Transfer Office.
Skin tissue model
The first model to be developed uses liver tissue cells, but Ramsinghani explained that the test is not tissue specific and the scaffold could be used to grow skin cells in 3D which could then be used to test nanoparticles.
“We believe we are poised to bring efficiencies into the cosmeceutical and drug discovery marketplace at the right time,” he added.
The scientists used the liver model to test the toxicity of cadmium telluride nanoparticles, and found that it appeared to be less toxic when tested with the 3D model than previous 2D tests had suggested.
Ramsinghani describes this as a pleasant surprise, but says such a finding must be approached with caution.
“It would be hasty to conclude that cadmium telluride is less toxic and thus, start consuming gobs of its every day with out bread and eggs.”
Instead, the team worked to the basic premise that cell and tissue behavior is much closer to reality when a three dimensional construct is used.
“What we have successfully concluded is that a 3D model is more appropriate for testing of nanoparticles and is a better replication of human cell behavior,” he said.
Source: Small DOI: 10.1002/smll.200801788In vitro toxicity testing of nanoparticles in 3D cell culture Jungwoo Lee, G. Daniel Lilly, R. Christopher Doty, Paul Podsiadlo and Nicholas A Kotov