Brett Smith for redOrbit.com – Your Universe Online
For years, cancer-research scientists have been using two-dimensional petri dish models to study and test potential treatments. But now, a team of scientists led by Drexel University’s Wei Sun has developed a method for 3-D printing living tumors – a development that could revolutionize cancer research.
According to a report on the development recently published the journal Biofabrication, the team was able to print out viable tumors by using a mixture of cervical cancer cells and a hydrogel substance that looks like a common ointment.
“This is the first time to report that one can build a 3D in vitro tumor model through 3D Printing technology,” said Sun, the director of Drexel’s research center at the Shanghai Advanced Research Institute, in a recent statement. “This may lead to a new paradigm for cancer research and for individual cancer therapies. We have developed a technological platform and would like to work with biologists and pathologists to encourage them to use the developed platform for 3D biology and disease studies.”
Because tumors within the body have a distinct surface area, form and cellular structure, cell culture samples grown in a lab come with inherent limitations, meaning information from tests using these specimens will vary from the response of an actual tumor to a treatment. Until now, these cell cultures were their best choice.
“Two-dimensional cell culture models are traditionally used for biology study and drug screening,” Sun said. “However, two-dimensional culture models can not represent true 3D physiological tissues so it lacks the microenvironment characteristics of natural 3D tissues in vivo. This inherent inadequacy leads to shortcomings in cancer research and anti-tumor drug development. On the other hand, 3D tumor models can represent true tumor 3D pathological organizations and will lead to a new paradigm for cancer study.”
[ Watch the Video: Researchers Create Live Cancer Tumors With A 3D Printer ]
In the study, the researchers took several main variables into account: width of nozzle, pace and pressure of extrusion, design and dimensions of deposition, as well as viscosity and temperature of substrates. The team was able to produce cancer cells with a 90 percent survival rate that grew into spheroid-shaped tumors in about eight days.
“The keys to keeping the cells alive were controlling the temperature of the nozzle and using a hearty strain of cancer cells,” Sun said. “We chose the Hela cell, which is a robust form of cervical cancer that has been used in research for many years. Because of this, we had a good idea as to how it would behave under certain conditions. This allowed us to control the variables of the extrusion process until we were able to successfully create a model.”
The researchers compared their 3-D model against a two-dimensional culture sample with a standard anti-cancer drug. The 3-D printed tumors exhibited more resistance to the chemical treatment method than the very same cancer cellular material grown inside a petri dish – an example of the difference that exists between test outcomes and success rates of cancer remedies.
The researchers said they plan to work on printing tumors made from multiple different cells – a characteristic often present in those extracted from cancer patients. They said they also want to find ways to connect the 3-D models to tissues and blood vessels that they have also printed, which would help to replicate how tumors grow in the body.
“We will try to understand the cell-cell and cell-substrate communication and immune responses for the printed tumor-like models,” Sun said. “Our goal is to take this tumor-like model and make it into a more of an in vivo simulation. And to apply it to study the development, invasion and metastasis of cancer, to test the efficacy and safety of new cancer drugs, as well as the specific therapy for individual cancer patient”
Image 2 (below): After eight days, the printed mixture of cervical cancer cells and hydrogel grows into living spheroid tumors -shown here in fluorescent dye. Credit: Wei Sun, Drexel University