VOA慢速英语2020--科学家3D打印出首个全尺寸人类心脏模型

American researchers say they have created the first full-size human heart model using 3D printing technology.

The model was made with a specially¹ developed 3D printer that uses biomaterials to produce a structure and tissues similar to a real human heart.

The researchers say the model heart can be a useful tool to train medical professionals in operations related to human heart function. It could also be used as a basis for new research on ways to use 3D printing technology to produce fully² operating hearts to replace in people.

The research was led by an engineering team at America's Carnegie Mellon University. Results were recently published in a paper in ACS Biomaterials Science and Engineering.

The team was led by biomedical engineering professor Adam Feinberg. The team had already developed a 3D printer that could "bioprint" collagen. Collagen is the main structural³ protein that is found in tissues throughout the human body.

The goal of the latest project was to use this same bioprinting technology to create a realistic, full-size model of a human heart.

Feinberg said in a statement his team was able to create such a model that doctors can carefully examine to prepare for heart operations. But the newly-created models also permit the doctors to "manipulate" the heart, to experience similar reactions to working with real tissue, he added.

Scientists have made 3D printed models of the human heart before. But those models were made of harder substances – such as plastic or rubber – that were not effective in copying the soft tissue material found in the human heart.

The new 3D printing process was also not easy, the Carnegie Mellon team said. This is because soft materials, such as collagen, start out as a liquid. When such substances are printed in air, they quickly collapse⁴ during the process.

So the researchers came up with their own method to 3D print soft materials. The method uses a gelatin substance to surround the structures during the printing so they do not collapse.

The team's new model heart is made from a material called alginate, a soft, natural substance made from seaweed. The researchers say alginate has very similar properties to tissues that make up the human heart.

For example, the researchers tested the 3D printed material with sutures, which doctors use to close up wounds during operations. The team said the alginate was able to stretch to support the sutures.

Once they had perfected the process, the researchers made additional changes to the 3D printer to produce larger objects. They were able to use MRI images from a patient to model and print a full-size human heart. MRI stands for magnetic resonance⁵ imaging, a system for producing electronic pictures of the organs inside the body.

Feinberg's team has also experimented with pieces of tissue designed to copy the function of individual heart elements - such as valves that open and close and realistic blood vessels⁶.

The researchers say they also successfully 3D printed a model of a heart artery⁷ that could be used to train doctors. The group says the same methods could be used to create other realistic organ models as well, such as livers or kidneys.

Former Carnegie Mellon student Eman Mirdamadi was another lead researcher on the project. He admitted that "major hurdles⁹" still prevent the bioprinting process from producing a full-sized, functional¹⁰ human heart. But the latest progress helps establish the "foundational groundwork" for such efforts, he said in a statement.

Words in This Story

3D printing – n. the process of printing a solid object from a digital model by printing many separate layers of the object

function – n. the way in which something works or operates

manipulate – v. to control something using the hands

gelatin – n. a clear substance made from animal bones that is used to make some foods and other substances

seaweed – n. a type of plant that grows in the sea

suture – n. a stitch used to sew up a cut or wound in a person's body

valve – n. a part of the heart that controls the amount of blood flow

artery – n. a thick tube that carries blood from the heart to other parts of the body

hurdle⁸ – n. a problem that has to be dealt with before further progress is made

groundwork – n. work that is done in preparation for work that will be done later

1 specially   

adv.特定地；特殊地；明确地

参考例句：

• They are specially packaged so that they stack easily.它们经过特别包装以便于堆放。
• The machine was designed specially for demolishing old buildings.这种机器是专为拆毁旧楼房而设计的。

2 fully   

adv.完全地，全部地，彻底地；充分地

参考例句：

• The doctor asked me to breathe in,then to breathe out fully.医生让我先吸气，然后全部呼出。
• They soon became fully integrated into the local community.他们很快就完全融入了当地人的圈子。

3 structural   

adj.构造的，组织的，建筑（用）的

参考例句：

• The storm caused no structural damage.风暴没有造成建筑结构方面的破坏。
• The North American continent is made up of three great structural entities.北美大陆是由三个构造单元组成的。

4 collapse   

vi.累倒；昏倒；倒塌；塌陷

参考例句：

• The country's economy is on the verge of collapse.国家的经济已到了崩溃的边缘。
• The engineer made a complete diagnosis of the bridge's collapse.工程师对桥的倒塌做了一次彻底的调查分析。

5 resonance   

n.洪亮；共鸣；共振

参考例句：

• Playing the piano sets up resonance in those glass ornaments.一弹钢琴那些玻璃饰物就会产生共振。
• The areas under the two resonance envelopes are unequal.两个共振峰下面的面积是不相等的。

6 vessels   

n.血管( vessel的名词复数 )；船；容器；（具有特殊品质或接受特殊品质的）人

参考例句：

• The river is navigable by vessels of up to 90 tons. 90 吨以下的船只可以从这条河通过。 来自《简明英汉词典》
• All modern vessels of any size are fitted with radar installations. 所有现代化船只都有雷达装置。 来自《现代汉英综合大词典》

7 artery   

n.干线，要道；动脉

参考例句：

• We couldn't feel the changes in the blood pressure within the artery.我们无法感觉到动脉血管内血压的变化。
• The aorta is the largest artery in the body.主动脉是人体中的最大动脉。

8 hurdle   

n.跳栏，栏架；障碍，困难；vi.进行跨栏赛

参考例句：

• The weather will be the biggest hurdle so I have to be ready.天气将会是最大的障碍，所以我必须要作好准备。
• She clocked 11.6 seconds for the 80 metre hurdle.八十米跳栏赛跑她跑了十一秒六。

9 hurdles   

n.障碍( hurdle的名词复数 )；跳栏；（供人或马跳跃的）栏架；跨栏赛

参考例句：

• In starting a new company, many hurdles must be crossed. 刚开办一个公司时，必须克服许多障碍。 来自《简明英汉词典》
• There are several hurdles to be got over in this project. 在这项工程中有一些困难要克服。 来自辞典例句

10 functional   

adj.为实用而设计的，具备功能的，起作用的

参考例句：

• The telephone was out of order,but is functional now.电话刚才坏了，但现在可以用了。
• The furniture is not fancy,just functional.这些家具不是摆着好看的，只是为了实用。