"Proteins are the building blocks for cell function and cell behavior, but their makeup in a cell is highly complex," Gao said. "You need to look at a number of indicators (biomarkers) to know what's going on."
The new process works like this: Gao and his team purchase antibodies that are known to bind with the specific biomarkers they want to test for in a cell. They pair quantum dots with the antibodies in a fluid solution, injecting it onto a tissue sample. Then, they use a microscope to look for the presence of fluorescent colors in the cell. If they see particular quantum dot colors in the tissue sample, they know the corresponding biomarker is present in the cell.
After completing one cycle, Gao and co-author Pavel Zrazhevskiy, a UW doctoral student in bioengineering, inject a low-pH fluid into the cell tissue that neutralizes the color fluorescence, essentially wiping the sample clean for the next round. Remarkably, the tissue sample doesn't degrade at all even after 10 such cycles, Gao said.
For cancer research and treatment, in particular, it's important to be able to look at a single cell at high resolution to examine its details. For example, if 99 percent of cancer cells in a person's body respond to a treatment drug, but 1 percent doesn't, it's important to analyze and understand the molecular makeup of that 1 percent that responds differently.
"When you treat with promising drugs, there are still a few cells that usually don't respond to treatment," said Gao. "They look the same, but you don't have a tool to look at their protein building blocks. This will really help us develop new drugs and treatment approaches."
The process is relatively low-cost and simple, and Gao hopes the procedure can be automated. He envisions a chamber to hold the tissue sample, and wire-thin pumps to inject and vacuum out fluid between cycles. A microsc
|Contact: Michelle Ma|
University of Washington