waiting for critical organs like kidneys, hearts, and livers

目前有數十萬人 在器官移植的名單上，

that could save their lives.

等待如腎、心及肝臟的重要器官

Unfortunately,

來挽救他們的生命。

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

很不幸地，

What if instead of waiting,

捐贈器官的數量遠遠供不應求。

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

如果不要用等待方式，

That's the idea behind bioprinting,

我們能從零開始， 製造全新客製化器官呢？

a branch of regenerative medicine currently under development.

那正是生物列印的理念，

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

它是再生醫學的一分支， 目前正在發展中。

but simpler tissues including blood vessels and tubes

我們尚無法列印複雜的器官，

responsible for nutrient and waste exchange

但簡單的組織，

are already in our grasp.

例如血管或負責營養 及廢物交換的管道等，

Bioprinting is a biological cousin of 3-D printing,

已有辦法列印出。

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

生物列印和 3D 立體列印是相關的，

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

是一種將材料層層疊加的技術，

Instead of starting with metal, plastic, or ceramic,

一次一層，建構出一個立體的物件。

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

不採用金屬、塑膠或陶土等原料，

a printable material that contains living cells.

器官及組織的 3D 立體列印機 是用「生物墨水」：

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

這是一種含有活體細胞的 可列印物質。

Mixed into those are millions of living cells

許多生物墨水的主要組成是 富含水的物質──即「水凝膠」。

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

墨水混合著數百萬的活體細胞

Some bioinks include a single type of cell,

和多種化學物質 以刺激細胞交流及成長。

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

有些生物墨水只含一種類型的細胞，

Let's say you want to print a meniscus,

而有些則結合多種細胞 以製造較複雜的構造。

which is a piece of cartilage in the knee

例如你想列印一個「半月板」，

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

那是膝蓋的一塊軟骨，

It's made up of cells called chondrocytes,

它可減少小腿脛骨 與大腿股骨間的摩擦。

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

半月板是由「軟骨細胞」所組成，

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

所以你的生物墨水 需要有很多軟骨細胞。

Or they might originate from a patient's own tissue

這些細胞可能來自實驗室 複製捐贈者的細胞，

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

或是取自病人的自體組織，

There are several printing techniques,

製成專屬的半月板，

and the most popular is extrusion-based bioprinting.

這樣較不會有身體排斥的狀況。

In this, bioink gets loaded into a printing chamber

目前有數種列印技術，

and pushed through a round nozzle attached to a printhead.

最常用的是「擠出式生物列印法」。

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

此法是將生物墨水裝入列印管中，

and can produce a continuous filament

然後擠壓通過一個 附在噴頭上的圓形噴嘴，

roughly the thickness of a human fingernail.

從一個直徑幾近 400 微米的噴嘴擠出，

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

且能形成連續的細線，

either onto a flat surface or into a liquid bath

其厚度與人的指甲相仿。

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

以電腦圖像或檔案 來導引細線的位置，

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

墨汁被擠到一個平面上 或液體容器中，

one thin strand at a time.

如此可協助構造成形，直到穩定。

After printing, some bioinks will stiffen immediately;

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。

others need UV light or an additional chemical or physical process

列印後，有些生物墨水會立刻變硬，

to stabilize the structure.

而有些需借助紫外線 或特別的化學、物理方法

If the printing process is successful,

來穩定結構。

the cells in the synthetic tissue

如果列印成功，

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

人造組織上的細胞

signaling to each other, exchanging nutrients, and multiplying.

會開始如同真正組織細胞般地運作：

We can already print relatively simple structures like this meniscus.

互通訊息、交換營養以及繁殖。

Bioprinted bladders have also been successfully implanted,

我們已能列印比較簡單的構造， 例如這個半月板。

and printed tissue has promoted facial nerve regeneration in rats.

生物列印的膀胱 已成功地被植入人體，

Researchers have created lung tissue, skin, and cartilage,

而列印組織已能加速 老鼠顏面神經的再生。

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

研究人員已能製造出 肺組織、皮膚、軟骨

However, replicating the complex biochemical environment

以及微型、具部分功能的 腎、肝及心臟。

of a major organ is a steep challenge.

然而，複製一個重要器官的 複雜生化環境

Extrusion-based bioprinting may destroy

是項艱難的挑戰。

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

擠出式生物列印法

or if the printing pressure is too high.

可能破壞墨水中許多細胞，

One of the most formidable challenges

如果噴嘴過小 或擠壓的壓力太高的話。

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

最難以克服的挑戰之一是

That's why the greatest successes so far

如何讓氧氣及養分供應到 實際大小器官的每個細胞。

have been with structures that are flat or hollow—

這就是為何目前最大的成就

and why researchers are busy developing ways

只在扁平或中空的構造上──

to incorporate blood vessels into bioprinted tissue.

也是為什麼研究人員忙於研發

There's tremendous potential to use bioprinting

在列印組織中加入血管的方法。

to save lives and advance our understanding

使用生物列印來拯救生命 具有極大潛能，

of how our organs function in the first place.

並可讓我們更了解器官如何運作。

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？