美国科学家制造三维模型模拟大脑功能

过圆圈中间的物质相互交换信号。当科学家让重
物掉到这个圆圈上，以模拟创伤性损伤时，这个
三维大脑模型中的神经元释放出了化学信号和电 信号，与受伤动物的大脑释放的信号类似。 It is
the first time scien
tists have been able to so closely imitate brain
reacted like a kitchen sponge, and it would compress
down and then partially spring back up. 卡普兰称，
这个培养皿中的大脑“没有四处飞溅”，其反应
更像是“厨房里的海绵，先是向下压缩，然后部
分反弹起来。” He said measurements of glutamate,
By adding nutrien
ts and growth factors, scientists kept the brainlike
tissue alive in an incubator for two months, at which
point they experimented
on it. 通过添加营养物质和生长因子，科学家把这
how disease, trauma and medical
treatments affect the brain — without the expense and
ethical challenges of clinical trials on people. 专家们
表示，这是科学家首次能在实验室里如此逼真地
neurons. It’s the best m
odel I’ve seen. “从与大脑的机械相似性来看，这是
一个相当不错的模仿，”詹姆斯· J· 希克曼(James J.
Hickman)说。他是中佛罗里达大学(University of
Central Florida)的纳米科学与技术教授，没有参与 这项研
Rosemarie Hunziker, program director of tissue
engineering and biomaterial at the Nat
ional Institute of Biomedical Imaging and
Bioengineering, which funded Dr. Kaplan’s research.
ath; both are useful but have limits. 研究人类大脑发
育的工作大多依赖于动物实验，或人死亡后获取
的大脑切片；两者都有用，但都具局限性。 Brain
models have been mostly two-dimensiona
l or made with a three-dimensional gel, said
neurons, a stand-in for gray
matter. By itself, silk did not encourage neurons to
produce axons, branches that transmit electrical pulses
to other neurons. 卡普兰
美国国家生物医学成像和生物工程研究所(National
Institut
e of Biomedical Imaging and Bioengineering)的组织
工程与生物材料项目主任罗斯玛丽· 亨齐克
(Rosemarie Hunziker)称，以前的大脑模型大多是
二维的，或是用三维凝胶制作。该研究所资助了 卡普兰的工作。 None
function in the laboratory, experts said. If researchers
can replicate it with hu
man neurons and enhance it to reflect other
neurological functions, it could be used for studying
还表示，过去的系统都没有复制大脑的灰质或白
质，也没有复制出神经元如何传导信号。“就算
你能让细胞在模型中存活，它们基本上也做不成 什么。” Dr. Kaplan
’s team found that a spongy silk material coated with
a positively charged polymer could culture rat
grew from the ring through the gel — the white matter
substitute — and sent
signals to neurons across the circle. 这些研究人员将
丝制材料做成一个圆圈，在其中心添加了胶原蛋
白凝胶。轴突从圆圈的一边长出来，通过替代白
nal brain model emitted chemical and electrical
signals similar to those in the brains of injured
animals. 生物工程师在培养皿中制成了相当于原始
灰质和白质
的材料，其中用了大鼠神经元，这些神经元能通
质的凝胶，把信号发送给圆圈另一边的神经元。 They got these neuron
s talking to each other, Dr. Hunziker said. No one’s
really shown that before. 亨齐克说，他们让“这些
神经元互相交流。以前没人真正做到了这一点。”
戴维· 卡普兰(David Kaplan)主持，于周一发表在
《美国科学院院刊》(PNAS)上。
这是用生物医学工程手段制造器官——比如心脏、
肺和肝脏——仿真模型的一个最新例子。 Most
studies of human brain development rely on animals
or on brain slices taken after de
的研究小组发现，一种涂有带正电聚合物的海绵
状丝制材料可以培养大鼠神经元，用以替代灰质。
丝制材料本身并不能让神经元产生轴突，也就是
把电脉冲传递给其他神经元的突出部分。 The researchers formed the silk material into a
doughnut and added collagen gel to the center. Axons
称这个模型的建造有点像“乐高用的方法”，是 一种“模块结构”，可以扩展成更复杂的形态。
It
is the first proof of principle that something like this
can be achieved outside of the body, she said. 她说，
dropped weights from different heights. 添加一种神
经毒素基本上会把神经元杀死，就像在真正的大
脑中那样。为了模拟
脑外伤，他们从不同高度让重物掉到模型上。 Dr.
Kaplan said the brain-in-a-dish didn’t go splat, but
the latest example of biomedical engineering being
used to make realistic mod
els of organs such as the heart, lungs and liver. 该研
究由塔夫茨大学(Tufts University)生物工程系主任
“受伤越重，激增的峰值越高。” Gordana
Vunjak-Novakovic, a biomedical engineering
professor at Columbia who has worked with
Dr. Kaplan on other studies, described the model as a
of those systems replicate the brain’s gray or white
matter, or how neurons communicate, Dr. Hunziker
said. Even if you get cells
to live in there, they don’t do much, she said. 亨齐克
实验室里制造的一个类似甜甜圈的东西，可以模
仿脑组织的一项基本功能。这个圆圈的环状部分
由丝材料制成，圈里面填的是胶原蛋白凝胶。 Bioengineers produ
ced a kind of rudimentary gray matter and white
matter in a dish, along with rat neurons that signaled
A doughnut created in a lab and made of silk on the
outside and collagen gel where the jelly ought to be
can mimic a basic functio
on of brain tissue, scientists have found. 科学家发现，
个类似脑的组织放在孵化器中，让其存活了两个
月，然后开始在它上面做试验。 Adding a
neurotoxin essentially killed the neurons, as it would in
a real brain. To simulate traumatic brain injury, they
究。“他们能够复制出最高水平的神经元功能。
这是我看到过的最好的模型。” The research, led
by David Kaplan, the chairman of the bioengineering
department at Tufts Univ
ersity, and published Monday in the journal PNAS, is
kind of Lego approach, a modular structure that can
be expanded and made mo
re complex. 哥伦比亚大学生物医学工程系教授戈
尔达娜· 乌尼亚克-诺瓦科维奇(Gordana Vunjak-
Novakovic)曾与卡普兰在其他研究上有过合作。她
one another across the doug
hnut’s center. When the scientists dropped weights on
the material to simulate traumatic injury, the neurons
in the three-dimensio
a neurotransmitter that surges in injury, showed that
the more severe the damage, the higher the spike in
glutamate. 他说，大脑受伤会导致神经
递质谷氨酸激增，而对模型中谷氨酸的测量显示，
Hickman, a professor of nanoscience technology at
the University of Central Fl
orida, who was not involved in the research. They’ve
been able to repeat the highest level of function of
模仿大
脑功能。如果研究人员能用人的神经元重建这个
模型，并提升到足以反映其他一些神经系统功能
的水平，那么这个模型或可用于研究疾病、创伤
和治疗如何影响大脑，从而避免人体临床试验的 高费用和伦理问题。 In terms of mechBiblioteka Baidunical
similarity to
the brain, it’s a pretty good mimic, said James J.