文章来源:未知 文章作者:meng 发布时间:2010-05-14 01:59 字体: [ ]  进入论坛

Tissue engineering has long held promise for building new organs to replace damaged livers, blood vessels1(血管) and other body parts. However, one major obstacle is getting cells grown in a lab dish to form 3-D shapes instead of flat layers. Researchers at the MIT-Harvard Division of Health Sciences and Technology (HST) have come up with(提出,想出) a new way to overcome that challenge, by encapsulating(封装) living cells in cubes and arranging them into 3-D structures, just as a child would construct buildings out of blocks.

The new technique, dubbed2(被称为) "micromasonry," employs a gel-like material that acts like concrete, binding3 the cell "bricks" together as it hardens. Ali Khademhosseini, assistant professor of HST, and former HST postdoctoral associate Javier Gomez Fernandez describe the work in a paper published online in the journal Advanced Materials.

The tiny cell bricks hold potential for building artificial tissue or other types of medical devices, says Jennifer Elisseeff, associate professor of biomedical engineering(生物医学工程学) at Johns Hopkins University, who was not involved in the research. "They're very elegant(高雅的,讲究的) and have a lot of flexibility4 in how you grow them," she says. "It's very creative."

To obtain single cells for tissue engineering, researchers have to first break tissue apart, using enzymes5(酶类) that digest the extracellular(细胞外的) material that normally holds cells together. However, once the cells are free, it's difficult to assemble them into structures that mimic6 natural tissue microarchitecture(微体系结构) .

Some scientists have successfully built simple tissues such as skin, cartilage(软骨) or bladder(膀胱) on biodegradable(生物可降解的) foam7 scaffolds(脚手架,支架) . "That works, but it often lacks a controlled microarchitecture," says Khademhosseini, who is also an assistant professor at Brigham and Women's Hospital. "You don't get tissues with the same complexity8 as normal tissues."

The HST researchers built their "biological Legos" by encapsulating cells within a polymer(聚合物) called polyethylene glycol (PEG9聚氧乙烯), which has many medical uses. Their version of the polymer is a liquid that becomes a gel when illuminated10, so when the PEG-coated cells are exposed to light, the polymer hardens and encases(包住) the cells in cubes with side lengths ranging from 100 to 500 millionths of a meter.

Once the cells are in cube form, they can be arranged in specific shapes using templates(模板,范本) made of PDMS, a silicon-based polymer used in many medical devices. Both template and cell cubes are coated again with the PEG polymer, which acts as a glue that holds the cubes together as they pack themselves tightly onto the scaffold surface.

After the cubes are arranged properly, they are illuminated again, and the liquid holding the cubes together solidifies11. When the template is removed, the cubes hold their new structure.

Gomez Fernandez and Khademhosseini used this method to build tubes that could function as capillaries12(毛细血管) , potentially helping13 to overcome one of the most persistent14 problems with engineered organs — lack of an immediate15 blood supply. "If you build an organ, but you can't provide nutrients16, it is going to die," says Gomez Fernandez, now a postdoctoral fellow at Harvard. They hope their work could also lead to a new way to make artificial liver or cardiac(心脏的) tissue.

Other researchers have developed a technique called organ printing to create complex 3-D tissues, but that process requires a robotic machine that is not in widespread use. The new technique does not require any special equipment. "You can reproduce this in any lab," says Gomez Fernandez. "It's very simple."

To get to the point where these engineered tissues could become clinically useful, "the short-term next step is really looking at different cell types and the viability17 of tissue growth," says Elisseeff. The researchers are now doing that, and they are also exploring the use of different polymers that could replace PEG and offer more control over cell placement.


1 vessels fc9307c2593b522954eadb3ee6c57480     
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
  • 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》
2 dubbed dubbed     
v.给…起绰号( dub的过去式和过去分词 );把…称为;配音;复制
  • Mathematics was once dubbed the handmaiden of the sciences. 数学曾一度被视为各门科学的基础。
  • Is the movie dubbed or does it have subtitles? 这部电影是配音的还是打字幕的? 来自《简明英汉词典》
3 binding 2yEzWb     
  • The contract was not signed and has no binding force. 合同没有签署因而没有约束力。
  • Both sides have agreed that the arbitration will be binding. 双方都赞同仲裁具有约束力。
4 flexibility vjPxb     
  • Her great strength lies in her flexibility.她的优势在于她灵活变通。
  • The flexibility of a man's muscles will lessen as he becomes old.人老了肌肉的柔韧性将降低。
5 enzymes 7881ad8ce9c83424f7874e70266ed2d8     
n. 酶,酵素
  • It was said that washing powders containing enzymes remove stains more efficiently. 据说加酶洗衣粉除污更有效。
  • Among the enzymes which are particularly effective are pepsin, papain. 在酶当中特别有效的是胃朊酶、木瓜酶。
6 mimic PD2xc     
  • A parrot can mimic a person's voice.鹦鹉能学人的声音。
  • He used to mimic speech peculiarities of another.他过去总是模仿别人讲话的特点。
7 foam LjOxI     
  • The glass of beer was mostly foam.这杯啤酒大部分是泡沫。
  • The surface of the water is full of foam.水面都是泡沫。
8 complexity KO9z3     
  • Only now did he understand the full complexity of the problem.直到现在他才明白这一问题的全部复杂性。
  • The complexity of the road map puzzled me.错综复杂的公路图把我搞糊涂了。
9 peg p3Fzi     
  • Hang your overcoat on the peg in the hall.把你的大衣挂在门厅的挂衣钩上。
  • He hit the peg mightily on the top with a mallet.他用木槌猛敲木栓顶。
10 illuminated 98b351e9bc282af85e83e767e5ec76b8     
  • Floodlights illuminated the stadium. 泛光灯照亮了体育场。
  • the illuminated city at night 夜幕中万家灯火的城市
11 solidifies b0f1c3548c8c3da1b2e353ad9a9b5a4c     
(使)成为固体,(使)变硬,(使)变得坚固( solidify的第三人称单数 ); 使团结一致; 充实,巩固; 具体化
  • Jelly solidifies as it gets cold. 肉冻冷却就凝固。
  • It is stirred with 10%sodium carbonate solution(50ml)and then with water (50ml), after which It'solidifies. 与10%碳酸钠溶液(50毫升)混合搅拌,然后再用50毫升水混合搅拌,从而析出固体。
12 capillaries d0d7ccc2f58ea09ec26e13a0d6ffd34a     
毛细管,毛细血管( capillary的名词复数 )
  • The blood flows from the capillaries back into the veins. 血从毛细血管流回静脉。
  • While Joe sleeps, a large percentage of his capillaries are inactive. 当乔睡觉时,他的毛细血管大部分是不工作的。
13 helping 2rGzDc     
  • The poor children regularly pony up for a second helping of my hamburger. 那些可怜的孩子们总是要求我把我的汉堡包再给他们一份。
  • By doing this, they may at times be helping to restore competition. 这样一来, 他在某些时候,有助于竞争的加强。
14 persistent BSUzg     
  • Albert had a persistent headache that lasted for three days.艾伯特连续头痛了三天。
  • She felt embarrassed by his persistent attentions.他不时地向她大献殷勤,使她很难为情。
15 immediate aapxh     
  • His immediate neighbours felt it their duty to call.他的近邻认为他们有责任去拜访。
  • We declared ourselves for the immediate convocation of the meeting.我们主张立即召开这个会议。
16 nutrients 6a1e1ed248a3ac49744c39cc962fb607     
n.(食品或化学品)营养物,营养品( nutrient的名词复数 )
  • a lack of essential nutrients 基本营养的缺乏
  • Nutrients are absorbed into the bloodstream. 营养素被吸收进血液。 来自《简明英汉词典》
17 viability FiHwY     
  • What is required to achieve or maintain such viability? 要达到或维持这种生存能力需要什么?
  • Scientists are experimenting to find ways to ensure the viability of seeds for even longer periods of time. 正如我们所说,科学家正在试验努力寻找让种子的生命力更加延长的方法。
TAG标签: body cells organ tissue