Light-on-a-chip
Human lungs have been created on a microchipMembrane
In part, a living chip that reproduces the functions of the human respiratory organ at the cellular level will open a new chapter in biomedical research and pharmaceuticals.
This is the opinion of its authors – Donald Ingber, director of the Weiss Bionics Institute, his colleagues at the institution, as well as scientists from Harvard Medical School and Boston Children's Hospital Boston.
The key element of the lungs is a three–layer membrane in the alveoli. It provides not only gas exchange, but also a number of other functions such as activation of the immune system. Such a membrane consists of cells of the pulmonary epithelium, permeable extracellular matrix and blood capillary cells. It is this "interface" that the researchers reproduced inside the microchannel chip.
Since the new chips are transparent, researchers can easily observe various reactions of living tissue to external stimuli under a microscope, which is difficult to achieve in the case of working with a real model organism, and even more so with a human (photo by Felice Frankel).The thinnest rubber membrane with many microscopic holes acted as a matrix.
On both sides of it, scientists placed living human cells, respectively capillary and pulmonary epithelial cells. From the latter side, the vacuum pump imitated the breathing cycle, and from the opposite side of the chip, scientists passed a liquid simulating blood flow.
To create a lung chip, it was necessary to combine the methods of the computer industry and micromechanics with tissue engineering (photo by the Wyss Institute for Biologically Inspired Engineering).On the part of lung cells, scientists introduced E. coli bacteria, and on the part of artificial capillaries – white blood cells.
Lung cells detected bacteria, through a porous membrane they activated vascular cells, which, in turn, triggered an immune response. So the white blood cells moved to the air chamber and destroyed the bacteria.
Among other things, experts have tested the impact on the lung-chip of various nanoparticles, which are contained in some products and are also pollutants of air and water. So it was found that the mechanical process of respiration increases the absorption of such particles by the walls of the lungs and many of the particles pass from the air duct into the blood. Some particles caused overproduction of free radicals and inflammation in the living cells in the device. Previously, researchers could observe such effects only on laboratory animals (illustration by the Wyss Institute for Biologically Inspired Engineering).
The creators of the chip assure that checking the effects of toxins on human lungs or, conversely, drugs with a new chip will be faster and less expensive than with previous methods. The plans include testing a new chip for gas exchange between blood and air, as well as the creation of similar chips – simulators of the intestine and bone marrow. Later, scientists will try to combine several such devices, taking a step towards a model "organism on a chip".
Details are set out in an article in Science (Dongeun Huh et al., Reconstructing Organ-Level Lung Functions on a Chip) and a press release from Harvard Medical School (Living, breathing human lung-on-a-chip: A potential drug-testing alternative).
Portal "Eternal youth" http://vechnayamolodost.ru28.06.2010