Researchers in Houston have developed a cost effective method for printing living cells, claiming almost a 100 percent survival rate. The method, which is akin to a modern version of ancient Chinese wood block printing, allow cells to be printed on any surface and in virtually any two dimensional shape. And while current inkjet printers adapted to print living cells can cost upwards of US$10,000 with a cell survival rate of around 50 percent, this simple new technique could see the cell stamps produced for around $1.
While Block-Cell-Printing, BloC-Printing for short, has its limitations, it is much slower and more labor intensive than inkjet and is as yet unable to print in three dimensions, the technology is still in its infancy. The researchers say that the technique can already print high definition patterns with cells as close together as 5 micrometers and it can be adapted to various cell types, all with remarkable survival rates. The average animal cell is around 10 to 20 micrometers wide.
"Cell printing is used in so many different ways now – for drug development and in studies of tissue regeneration, cell function, and cell-cell communication," says lead researcher from Houston Methodist Research Institute Dr Lidong Qin. "Such things can only be done when cells are alive and active. A survival rate of 50 to 80 percent is typical as cells exit the inkjet nozzles. By comparison, we are seeing close to 100 percent of cells in BloC-Printing survive the printing process. We feel the current technologies are inadequate. Inkjet-based cell printing leaves many of the cells damaged or dead. We wanted to see if we could invent a tool that helps researchers obtain arrays of cells that are alive and still have full activity.”
The technique uses microfluidic physics to lead living cells into a series of J shaped catches in a silicone mold. The cells flow down a column and fill these traps and once one is full they flow onto the next in the series, creating a line of cells. The lines on the face of the mold are shaped into a grid pattern predetermined during manufacturing. Once loaded the mold can then be used much like a child’s rubber stamp, where cells are applied to a surface such as a growth medium, simply with a steady hand.
Already Qin has put the BloC-Printing to the test by printing a grid of brain cells in one study and examining the growth of cancer cells in another.
"The cell junctions we created may be useful for future neuron signal transduction and axon regeneration studies," Qin says of the initial testing with brain cells. "Such work could be helpful in understanding Alzheimer's disease and other neurodegenerative diseases."
"We looked at cancer cells for their protrusion generation capability, which correlates to their malignancy level," Qin explains in regard to subsequent trails using human breast cancer cells. "Longer protrusion means more aggressive cancer cells. The measurement may help to diagnose a cancer's stage."
The research was published in Proceedings of the National Academy of Sciences.