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  3. Modern offices may scorn the stuff, but paper has found a new use in the laboratory — as the basis for 3D models of tumours and

Modern offices may scorn the stuff, but paper has found a new use in the laboratory — as the basis for 3D models of tumours and

admin2012-06-20  48
问题     Modern offices may scorn the stuff, but paper has found a new use in the laboratory — as the basis for 3D models of tumours and damaged hearts.
    Chemist George Whitesides and his colleagues at Harvard University reckon that the balls of cells they have grown at the centre of stacked paper could help us better understand how tumours and damaged hearts respond to drugs, and even to select therapies most suited to individuals.
    Cells tend to be grown on flat plates in the lab, which isn’t representative of the 3D structure of cells in the body. "It’s nothing like human tissue," says Whitesides. In our bodies, cells are exposed to natural concentration gradients: the further away they are from major blood vessels, the less oxygen and nutrients they get. But in 2D cell cultures, such gradients aren’t present. "We need to move away from those boring flatlands that cell culture dishes represent," says cell biologist Emmanuel Reynaud who was not involved in the research.
    Although techniques for growing cells in 3D exist, many are time-consuming and far from perfect. For example, once the cells have grown, the cultures need to be sliced with a knife to be analysed. "Not only does this kill some cells, it’s extremely difficult to do," Whitesides says. His group has now developed a cheap alternative.
    The team start by spraying a gel containing their cells onto small sheets of sterile chromatography paper (无菌色谱纸). The cells they used included human lung cancer cells, human fibroblasts (纤维原细胞), which make up connective tissue, and mouse immune cells. "I tried everything I could get my hands on," says Whitesides.
    The cells seeped through the paper "like coffee through a napkin (餐巾)", he says. When the researchers stacked up eight sheets of cell-infused paper and suspended them in an oxygen and nutrient-rich broth (液体培养基), they found that the cells grew into a ball.
    To analyse how these cells behaved, the researchers simply peeled off the layers one at a time and analysed them individually. It seemed that the outer cells closer to the medium were nourished while the cells on the inside showed signs of being starved, which is what you would expect to happen to a tumour inside the body.
What does Whitesides think of cutting the cell cultures to do analysis?
选项 A、It is the most useful for treating tumors.
B、It needs too much time to finish.
C、It is difficult and has imperfection.
D、It is very cheap to operate.
答案C
解析 第四段倒数第二句提到，Whitesides说道，这不仅会杀死一些细胞，而且这么做很困难。由此可知选项中与文意符合的是[C]，imperfection对应文中的kill some cells。
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