A recurring theme of this blog is that automation and miniaturization of laboratory devices are speeding up the rate of advance of biological science and biotechnology. Miniaturization is being done in conjunction with parallelization to enable faster and cheaper testing and manipulation of cells and materials. This trend is analogous to the acceleration of computers by making their parts ever smaller and many technologies developed by the computing industry are helping to enable the acceleration of biological advances. Well, yet another example of this trend is an MIT report on the development of miniaturized arays for growing and testing embryonic stem cells.
CAMBRIDGE, Mass.--An MIT team has developed new technology that could jump-start scientists' ability to create specific cell types from human embryonic stem cells, a feat with implications for developing replacement organs and a variety of other tissue engineering applications.
The scientists have already identified a simple method for producing substantially pure populations of epithelial-like cells from human embryonic stem cells. Epithelial cells could be useful in making synthetic skin.
Human embryonic stem cells (hES) have the potential to differentiate into a variety of specialized cells, but coaxing them to do so is difficult. Several factors are known to influence their behavior. One of them is the material the cells grow upon outside the body, which is the focus of the current work.
"Until now there has been no quick, easy way to assess how a given material will affect cell behavior," said Robert Langer, the Germeshausen Professor of Chemical and Biomedical Engineering. Langer is the senior author of a paper on the work that will appear in the June 13 online issue of Nature Biotechnology.
The new technique is not only fast; it also allows scientists to test hundreds to thousands of different materials at the same time. The trick? "We miniaturize the process," said Daniel G. Anderson, first author of the paper and a research associate in the Department of Chemical Engineering. Anderson and Langer are coauthors with Shulamit Levenberg, also a chemical engineering research associate.
The team developed robotic technology to deposit more than 1,700 spots of biomaterial (roughly 500 different materials in triplicate) on a glass slide measuring only 25 millimeters wide by 75 long. Twenty such slides, or microarrays, can be made in a single day. Exposure to ultraviolet light polymerizes the biomaterials, making each spot rigid and thus making the microarray ready for "seeding" with hES or other cells. (In the current work, the team seeded some arrays with hES and some with embryonic muscle cells.)
Each seeded microarray can then be placed in a different solution, including such things as growth factors, to incubate. "We can simultaneously process several microarrays under a variety of conditions," Anderson said.
Another plus: the microarrays work with a minimal number of cells, growth factors and other media. "That's especially important for human embryonic stem cells because the cells are hard to grow, and the media necessary for their growth are expensive," Anderson said. Many of the media related to testing the cells, such as antibodies, are also expensive.
In the current work, the scientists used an initial screening to find especially promising biomaterials for the differentiation of hES into epithelial cells. Additional experiments identified "a host of unexpected materials effects that offer new levels of control over hES cell behavior," the team writes, demonstrating the power of quick, easy screenings.
My guess is that this technique is also usable for testing adult stem cells and more differentiated cell types.
This report brings to mind a pair of recent reports by USCD researchers where they tested tens of thousands of molecules to find a molecule called cardiogenol C that will turn embryonic stem cells into heart muscle cells and a molecule called reversine that will turn adult muscle cells into stem cells. In each case the ability to develop screening methods to test the effects of large numbers of molecules on cells in culture enabled the discovery of useful molecules.
The development of the enabling technologies that accelerate by orders of magnitude the search for compounds that change the internal regulatory state of cells is more important than any particular discovery made with the tools. There are many useful discoveries that could be made sooner if only ways can be developed to do tests more cheaply, more rapidly, more accurately, and with greater sensitivity.
|Share |||Randall Parker, 2004 June 15 03:14 AM Biotech Advance Rates|