A better way `to create human stem cells`
Washington: MIT scientists, including an Indian-origin researcher, claim to have developed a better way of creating human stem cells which could become any other body
cell and treat any disease that involves injuries to cells.
Most materials now used to grow human stem cells include cells or proteins that come from mice embryos, which help stimulate stem cell growth but would likely cause an
immune reaction if injected into a human patient. Moreover, largescale production of such cells often becomes difficult. Now, Krishanu Saha and colleagues at Massachusetts
Institute of Technology have devised a synthetic surface that includes no foreign animal material and allows stem cells to stay alive, and even continue reproducing themselves for at least three months, the `Nature Materials` journal reported.
It`s also the first synthetic material that allows single cells to form colonies of identical cells, which is necessary to identify cells with desired traits and has been difficult to achieve with existing materials, according to the scientists.
Human stem cells can come from two sources – embryonic cells or body cells that have been reprogrammed to an immature state. That state, known as pluripotency, allows the cells to develop into any kind of specialised body cells. It can treat ailments like multiple sclerosis and spinal cord injury.
To engineer such treatments, researchers would need to be able to grow stem cells in the lab for an extended period of time, manipulate their genes, and grow colonies of
identical cells after they have been genetically modified.
"Current growth surfaces, consisting of a plastic dish coated with a layer of gelatin and then a layer of mouse cells or proteins, are notoriously inefficient.
"For therapeutics, you need millions and millions of cells. 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," Saha said.
The MIT team created about 500 polymers (long chains of repeating molecules) that varied in those traits, grew stem cells on them and analysed each polymer`s performance.
After correlating surface characteristics with performance, they found that there was an optimal range of surface hydrophobicity but varying roughness and stiffness did not have much effect on cell growth.
They also adjusted the composition of the materials, including proteins embedded in the polymer. 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.
Using their best-performing material, the team got stem cells -- both embryonic and induced pluripotent – to continue growing and dividing for up to three months. They
were able to generate large quantities of cells in millions.
"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," team member Daniel Anderson said.