VOA慢速英语2020--科学家3D打印出首个全尺寸人类心脏模型

（单词翻译）

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