How to 3D print human tissue - Taneka Jones

譯者: Ann Chen 審譯者: Helen Chang

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

目前有數十萬人 在器官移植的名單上，

waiting for critical organs like kidneys, hearts, and livers

等待如腎、心及肝臟的重要器官

that could save their lives.

來挽救他們的生命。

Unfortunately,

很不幸地，

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

捐贈器官的數量遠遠供不應求。

What if instead of waiting,

如果不要用等待方式，

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

我們能從零開始， 製造全新客製化器官呢？

That’s the idea behind bioprinting,

那正是生物列印的理念，

a branch of regenerative medicine currently under development.

它是再生醫學的一分支， 目前正在發展中。

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

我們尚無法列印複雜的器官，

but simpler tissues including blood vessels and tubes

但簡單的組織，

例如血管或負責營養 及廢物交換的管道等，

responsible for nutrient and waste exchange

are already in our grasp.

已有辦法列印出。

Bioprinting is a biological cousin of 3-D printing,

生物列印和 3D 立體列印是相關的，

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

是一種將材料層層疊加的技術，

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

一次一層，建構出一個立體的物件。

Instead of starting with metal, plastic, or ceramic,

不採用金屬、塑膠或陶土等原料，

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

器官及組織的 3D 立體列印機 是用「生物墨水」：

a printable material that contains living cells.

這是一種含有活體細胞的 可列印物質。

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

許多生物墨水的主要組成是 富含水的物質──即「水凝膠」。

Mixed into those are millions of living cells

墨水混合著數百萬的活體細胞

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

和多種化學物質 以刺激細胞交流及成長。

Some bioinks include a single type of cell,

有些生物墨水只含一種類型的細胞，

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

而有些則結合多種細胞 以製造較複雜的構造。

Let’s say you want to print a meniscus,

例如你想列印一個「半月板」，

which is a piece of cartilage in the knee

那是膝蓋的一塊軟骨，

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

它可減少小腿脛骨 與大腿股骨間的摩擦。

It’s made up of cells called chondrocytes,

半月板是由「軟骨細胞」所組成，

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

所以你的生物墨水 需要有很多軟骨細胞。

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

這些細胞可能來自實驗室 複製捐贈者的細胞，

Or they might originate from a patient’s own tissue

或是取自病人的自體組織，

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

製成專屬的半月板，

這樣較不會有身體排斥的狀況。

There are several printing techniques,

目前有數種列印技術，

and the most popular is extrusion-based bioprinting.

最常用的是「擠出式生物列印法」。

In this, bioink gets loaded into a printing chamber

此法是將生物墨水裝入列印管中，

and pushed through a round nozzle attached to a printhead.

然後擠壓通過一個 附在噴頭上的圓形噴嘴，

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

從一個直徑幾近 400 微米的噴嘴擠出，

and can produce a continuous filament

且能形成連續的細線，

roughly the thickness of a human fingernail.

其厚度與人的指甲相仿。

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

以電腦圖像或檔案 來導引細線的位置，

either onto a flat surface or into a liquid bath

墨汁被擠到一個平面上 或液體容器中，

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

如此可協助構造成形，直到穩定。

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

列印機的速度很快，一次一縷細線， 約半小時就可製出半月板。

one thin strand at a time.

After printing, some bioinks will stiffen immediately;

列印後，有些生物墨水會立刻變硬，

others need UV light or an additional chemical or physical process

而有些需借助紫外線 或特別的化學、物理方法

to stabilize the structure.

來穩定結構。

If the printing process is successful,

如果列印成功，

the cells in the synthetic tissue

人造組織上的細胞

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

會開始如同真正組織細胞般地運作：

signaling to each other, exchanging nutrients, and multiplying.

互通訊息、交換營養以及繁殖。

We can already print relatively simple structures like this meniscus.

我們已能列印比較簡單的構造， 例如這個半月板。

Bioprinted bladders have also been successfully implanted,

生物列印的膀胱 已成功地被植入人體，

and printed tissue has promoted facial nerve regeneration in rats.

而列印組織已能加速 老鼠顏面神經的再生。

Researchers have created lung tissue, skin, and cartilage,

研究人員已能製造出 肺組織、皮膚、軟骨

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

以及微型、具部分功能的 腎、肝及心臟。

However, replicating the complex biochemical environment

然而，複製一個重要器官的 複雜生化環境

of a major organ is a steep challenge.

是項艱難的挑戰。

Extrusion-based bioprinting may destroy

擠出式生物列印法

可能破壞墨水中許多細胞，

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

如果噴嘴過小 或擠壓的壓力太高的話。

or if the printing pressure is too high.

One of the most formidable challenges

最難以克服的挑戰之一是

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

如何讓氧氣及養分供應到 實際大小器官的每個細胞。

That’s why the greatest successes so far

這就是為何目前最大的成就

have been with structures that are flat or hollow—

只在扁平或中空的構造上──

and why researchers are busy developing ways

也是為什麼研究人員忙於研發

to incorporate blood vessels into bioprinted tissue.

在列印組織中加入血管的方法。

There’s tremendous potential to use bioprinting

使用生物列印來拯救生命 具有極大潛能，

to save lives and advance our understanding

並可讓我們更了解器官如何運作。

of how our organs function in the first place.

And the technology opens up a dizzying array of possibilities,

科技開拓了極多的無限可能，

such as printing tissues with embedded electronics.

例如內置電子設備的列印組織。

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

有朝一日，我們能否製造 超越目前人體性能的器官，

or give ourselves features like unburnable skin?

或製造具特色的物件， 例如不可燃的皮膚嗎？

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

藉由列印及置換器官， 人類的生命能延長多久呢？

And exactly who—and what—

到底是誰──是什麼東西──

will have access to this technology and its incredible output?

能使用到這項科技 與它驚人的產品呢？