How to 3D print human tissue - Taneka Jones

翻译人员: Evelyn Luan 校对人员: Harper Chang

There are currently hundreds of thousands of people on transplant lists,

目前有数十万人 在器官移植名单上，

waiting for critical organs like kidneys, hearts, and livers

等待重要器官捐赠， 像是肾、心脏和肝，

that could save their lives.

来拯救他们的生命。

Unfortunately,

很遗憾，

there aren’t nearly enough donor organs available to fill that demand.

器官捐赠供不应求。

What if instead of waiting,

如果除了等待，

we could create brand-new, customized organs from scratch?

我们还有办法从无到有， 创造出全新的、定制的器官呢？

That’s the idea behind bioprinting,

这就是生物打印的理念。

a branch of regenerative medicine currently under development.

生物打印是再生医学的分支， 目前处于发展阶段，

We’re not able to print complex organs just yet,

我们尚未能打印出复杂的器官，

but simpler tissues including blood vessels and tubes

但例如血管和负责 交换营养和废物的管道

responsible for nutrient and waste exchange

这些较简单的组织

are already in our grasp.

已经在我们掌握之中。

Bioprinting is a biological cousin of 3-D printing,

生物打印和 3D 打印原理相似，

a technique that deposits layers of material on top of each other

将层层的材料堆叠在一起，

to construct a three-dimensional object one slice at a time.

一次一层，建构出一个三维物体。

Instead of starting with metal, plastic, or ceramic,

普通的 3D 打印机 使用金属、塑料或陶瓷，

a 3-D printer for organs and tissues uses bioink:

而制作器官和组织的 3D 打印机使用“生物墨水”：

a printable material that contains living cells.

一种含有活细胞的 可打印材料。

The bulk of many bioinks are water-rich molecules called hydrogels.

许多生物墨水的主体是 一种富含水的分子，称作水凝胶，

Mixed into those are millions of living cells

水凝胶里混合了上百万个活细胞

as well as various chemicals that encourage cells to communicate and grow.

和各种用来促进细胞交流 和生长的化学物质。

Some bioinks include a single type of cell,

有些生物墨水只含单一 一种细胞，

while others combine several different kinds to produce more complex structures.

有些则结合许多不同种的细胞， 来制造出更复杂的结构。

Let’s say you want to print a meniscus,

假设你想要打印一个半月板，

which is a piece of cartilage in the knee

半月板是膝盖里的一块软骨，

that keeps the shinbone and thighbone from grinding against each other.

用来避免胫骨和股骨互相摩擦。

It’s made up of cells called chondrocytes,

它由软骨细胞组成，

and you’ll need a healthy supply of them for your bioink.

你需要有健康的软骨组织供应， 来制作你的生物墨水，

These cells can come from donors whose cell lines are replicated in a lab.

这些细胞可能来自捐赠者，他们 的细胞系在实验室里被复制，

Or they might originate from a patient’s own tissue

这些细胞也可能来自 病患自身的组织，

to create a personalized meniscus less likely to be rejected by their body.

这种定制的半月板 可以有效避免发生排斥反应。

There are several printing techniques,

现在有几种打印技术，

and the most popular is extrusion-based bioprinting.

其中最常用的是 挤压式生物打印。

In this, bioink gets loaded into a printing chamber

这项技术将生物墨水 载入打印机，

and pushed through a round nozzle attached to a printhead.

然后将它挤入 打印头上的柱状喷嘴。

It emerges from a nozzle that’s rarely wider than 400 microns in diameter,

墨水会从喷嘴挤出，喷嘴的直径 一般不会超过 400 微米，

and can produce a continuous filament

可以挤出连续不断的线丝，

roughly the thickness of a human fingernail.

厚度和人的指甲差不多。

A computerized image or file guides the placement of the strands,

计算机图像或档案

会引导线丝布局在平面，

either onto a flat surface or into a liquid bath

或是辅助固定结构的液槽里 直到其稳定。

that’ll help hold the structure in place until it stabilizes.

These printers are fast, producing the meniscus in about half an hour,

打印机的速度很快， 一次一线的制造出一个半月板，

one thin strand at a time.

只要半小时。

After printing, some bioinks will stiffen immediately;

打印完成后， 有些生物墨水会立即变硬；

others need UV light or an additional chemical or physical process

有些则需要紫外线， 或额外的化学或物理加工

to stabilize the structure.

来稳定结构。

If the printing process is successful,

如果打印过程顺利的话，

the cells in the synthetic tissue

人造组织里的细胞

will begin to behave the same way cells do in real tissue:

会开始表现得 和真实组织里的细胞一样：

signaling to each other, exchanging nutrients, and multiplying.

互相发出信号、 交换养分以及分裂繁殖。

We can already print relatively simple structures like this meniscus.

我们已经能够打印出 像半月板这样相对简单的结构，

Bioprinted bladders have also been successfully implanted,

也已经成功植入过 生物打印的膀胱，

and printed tissue has promoted facial nerve regeneration in rats.

打印出来的组织还成功 促进了老鼠脸部神经再造。

Researchers have created lung tissue, skin, and cartilage,

研究人员已经创造出 人造肺组织、皮肤及软骨，

as well as miniature, semi-functional versions of kidneys, livers, and hearts.

还有微缩版、半功能性的 肾、肝和心脏。

However, replicating the complex biochemical environment

然而，复制主要器官 复杂的生化环境

of a major organ is a steep challenge.

是一项严峻的挑战。

Extrusion-based bioprinting may destroy

挤压式生物打印可能会破坏

a significant percentage of cells in the ink if the nozzle is too small,

墨水里很大一部分的细胞， 如果喷头太小

or if the printing pressure is too high.

或打印压力太高。

One of the most formidable challenges

其中一项最艰巨的挑战，

is how to supply oxygen and nutrients to all the cells in a full-size organ.

是如何为一个原尺寸的器官里 所有的细胞供给氧气和营养。

That’s why the greatest successes so far

这就是为什么到目前为止， 最成功的案例

have been with structures that are flat or hollow—

都是平坦或空心的结构，

and why researchers are busy developing ways

这也是为什么 研究人员正积极研发

to incorporate blood vessels into bioprinted tissue.

将血管纳入生物打印中的方法。

There’s tremendous potential to use bioprinting

生物打印具有极大的潜能，

to save lives and advance our understanding

它可以用来拯救生命，

以及提高我们对器官运作的了解。

of how our organs function in the first place.

And the technology opens up a dizzying array of possibilities,

这项科技开启了 一系列的可能性，

such as printing tissues with embedded electronics.

像是用嵌入式电子产品 打印组织。

Could we one day engineer organs that exceed current human capability,

在未来，我们是否能够设计出 超越现在人类能力的器官，

or give ourselves features like unburnable skin?

或是赋予人们特殊功能， 例如不可燃的皮肤？

How long might we extend human life by printing and replacing our organs?

打印及更换器官 能延长人类寿命多久？

And exactly who—and what—

什么人，什么领域

will have access to this technology and its incredible output?

有权使用这项科技 和其惊人的成果？