By Liz Townsend

Researchers at the Massachusetts Institute of Technology (MIT) have refined the process for multiplying induced pluripotent stem cells (iPS cells) and grown millions of cells that continue to divide for at least three months. Their work, described in the August 22 issue of Nature Materials, is another step forward in the development of these versatile cells that are obtained without harming human beings.

"For therapeutics, you need millions and millions of cells," Krishanu Saha, one of the first authors of the report, said in an MIT press release. "If we can make it easier for the cells to divide and grow, that will really help to get the number of cells you need to do all of the disease studies that people are excited about."

In addition to requiring a vast number of cells, currently iPS cells are grown with the help of proteins derived from animals such as mice, which could cause an immune system reaction when the cells are introduced into humans, according to the press release.

The MIT researchers created various types of surfaces consisting of polymers, or long chains of repeating molecules, that would provide the platform where the iPS cells would grow, Asian News International reported. The polymers each had different characteristics--including water-repelling behaviour, roughness, and stiffness--that scientists could compare and determine which showed the greatest growth.

"They found that the best polymers contained a high percentage of acrylates, a common ingredient in plastics, and were coated with a protein called vitronectin, which encourages cells to attach to surfaces," according to the press release. Cells multiplied on this surface showed remarkable levels of growth and endurance. The surface did not contain any material from animals, which would make the cells safer for patients.

The researchers intend to continue on this promising avenue of study. "We want to better understand the interactions between the cell, the surface and the proteins, and define more clearly what it takes to get the cells to grow," said MIT Professor Daniel G. Anderson.