曼彻斯特大学(University of Manchester)的Andre Geim研究团队，在英国工程暨物理科学研究委员会(The Engineering and Physical Sciences Research Council)的资助下，首次公布量测到“细胞的心跳”。Geim教授说：「一旦我们知道了细胞正常的电力图谱，就能观察到药物是如何影响细胞。也可以在进行动物或人体试验前，先一步作好药物测试的安全预防措施。此外，细胞电力的测试也可被用来观测微生物对环境的污染等情况。」
为了测试细胞正常的活动力，Andre Geim研究团队修改了原本测试微磁场的超导体(superconductor)，但是，很不幸的，由于讯号太弱所以无法测试到酵母菌细胞的活动力，不过，这也是首次用超导体来测试活体细胞的例子。紧接着，不气馁的研究人员选择乙醇(alcohol或称ethanol)，事实上是伏特加酒(vodka)来激起细胞的反应，大家都知道乙醇会增加细胞膜的通透性，希望由此加大测试讯号的强度，后来终于成功了。当酵母菌尝到伏特加的酒味，研究人员从探针上看到电讯号，Geim教授说：「这大概是酵母菌的最后一口气吧！研究人员给酵母菌喝了太多酒，后来把它给毒死了。」
虽然不如大家先前所预期，希望能看到酵母菌的心电图 (cardiogram)，但能看到活体细胞的微小电讯号，研究人员还是十分兴奋。这个电讯号是目前所有测量统计中最小的，大约只有现今侦测到最小值的一百分之一，大约只有10个电子流过的电流量。目前研究人员持续对侦测器的敏感度进行修改，下次还要对阿米巴原虫进行量测。毕竟酵母菌是被灌醉后才量测到讯号的，而且电讯号真的很弱。研究人员希望未来真的能看到细胞的心电图，便能利用这些电力图谱进行更多细胞实验的判断。
(资料来源 : Bio.com)
英文原文：
A New Study of Living Cells Could Revolutionize The Way We Test Drugs
04/11/07 -- Researchers have made a breakthrough by detecting the electrical equivalent of a living cell?s last gasp. The work takes them a step closer to both seeing the ?heartbeat? of a living cell and a new way to test drugs.
To stay alive, individual biological cells must transfer electrically charged particles, called ions across their cell membranes. This flow produces an electrical current that could, in principle, be detected with sensitive enough equipment. The recognition of such electrical activity would provide a kind of ?cellular cardiogram?, allowing the daily functioning of the cell to be monitored in a similar way to a cardiograph showing the workings of a human heart.
With funding from the Engineering and Physical Sciences Research Council (EPSRC), Professor Andre Geim at the University of Manchester and his team have set out to make the first measurement of a cellular ?heartbeat?.
"Once we know the average or usual pattern of electrical activity in a cell, we can see how different drugs affect it," says Professor Geim. This would put an early safeguard into the system that could be applied long before the drug was tested on animals or even humans. In addition, the electrical activity test could be used to monitor the effects of pollution on naturally occurring micro-organisms in the environment.
To detect a cell?s normal activity, Andre Geim and fellow researchers modified apparatus used originally to detect weak magnetic fields in superconductors*. Unfortunately, these modifications reduced the sensitivity of the technique, and the normal activity of the yeast cell could not be detected. This is the first time such a technique has been used on a living cell.
Not to be defeated, the researchers went about livening things up. They chose to invoke what any self-respecting party-goer would: alcohol. "We added ethanol ? which is essentially vodka ? to provoke a response from the cell. Ethanol is known to increase the transparency of cellular membranes which we hoped would give a signal we could detect," says Dr Irina Barbolina, who carried out the experiments.
It worked. As soon as the yeast got a taste of the vodka, the probe registered an electrical signal. A drunken hiccup perhaps? "It was probably the last gasp of the dying cell," says Professor Geim. The researchers had added so much ethanol that it poisoned the cell.
Although not the cardiogram they had hoped for, the electrical signal was the smallest yet detected from a living cell, around 100 times smaller than anything previously detected. It added up to an electrical current of just 10 moving electrons. It has given the team confidence that equipment sensitive enough to measure a cell?s heartbeat can be developed.
"We already have some ideas about how to improve the sensitivity of the detector in water and next time we will also use a more active micro-organism such as an amoeba. Yeast is a subdued organism and doesn?t generate much activity," says Professor Geim. "Probably, the most important outcome is that we defined an important goal. Cellular cardiograms can no longer be seen as absurd or science-fictional. If not us then someone else will soon develop a technique sensitive enough for such studies."
Source: Engineering and Physical Sciences Research Council
上一篇：日本发现生殖细胞回避自然死亡的机制 下一篇：Cell：控制干细胞自我保持的重要基因Zfx
