电子组织，监测细胞
电子组织，监测细胞纳米电子支架可以支持活体组织。http://www.techreviewchina.com/upload/article/picture/1347859063294.jpg
有线支架：藻朊素（白色的）是一种从海藻中提取的材料，被用于传统的细胞支架。支架周围被镀上纳米级金属丝（伪色棕色）从而形成三维的电子支架。（图片来源：Charles Lieber and Daniel Kohane）
哈佛大学的研究人员构造出融合了生物组织和纳米电子器件的材料，直接地说，就是晶体管和细胞构成的网状物。
关于这一机械化有机体组织的研究被发表在《自然•材料学》（Nature Materials）杂志的网络版上。它可以支持细胞生长，也可同时监测着这些细胞的活动。作者写道，机械化有机体组织允许研究人员即时追踪细胞在三维环境中如何对药物的反应，从而改进体外药物筛选。对于研发直接与神经系统传递信息的假肢以及可感知创伤和疾病并作出反应的组织植入物来说，这也是第一步。
此前，为了探测生物系统的电活动，科学家已经开发了扁平灵活的装置。它能沿着一个器官外侧伸展，例如心脏，大脑或者皮肤（查看“制造能够伸展的电子设备”）。但是这些材料只能在组织表面监控电活动。
新的支架是由一个研究团队制造的。2012年《科技创业》的TR35之一田博之也是这个团队的成员。
此外，研究的团队还包括哈佛大学的化学家查尔斯• 利伯（Charles Lieber）；波士顿儿童医院生物材料和药物传递实验室的主任丹尼尔•科恩（Daniel Kohane）以及麻省理工学院的化学工程师和学院教授罗伯特•兰格（Robert Langer）。这个团队着手去设计一个使电子器件直接地与活体生物组织结合的三维支架。
纳米电子支架是薄金属纳米电线构成的网状物。它既可以伸直也可以弯曲，其间散布微小的能探测电活动的晶体管。研究者折叠或者转动这种网状物，让它们形成三维结构，分别来模拟一块组织或者一段血管。结果造出了既疏松又灵活的支架，对于电子元件来说这可不容易。利伯说：“从力学上来讲，这些支架是目前已制造的电子材料中最柔软的一种。”
随后，这一支架和可以被植入细胞，或和其他传统生物材料（例如胶原蛋白）结合，成为混合支架。利伯补充到：“从材料学的远景来看，这种功能显示，你几乎可以将这种电子网状物和任何东西结合。”
为了测试设备的感知能力，研究团队用活细胞进行了实验。他们在支架上生长了神经元，然后成功地监控到细胞对兴奋型神经递质反应的兴奋活动。他们还观察了心脏细胞组织，发现一边的心脏细胞和另一边相比，搏动方式略有不同。他们也在一段由卷曲结构和平滑肌细胞构成的的简化血管内外监测了pH值的变化。
利伯说，这种在不同组织中监测药物反应的支架，已经让许多制药公司很感兴趣。他说：“那是最近期的应用，但不是最终目标。”利伯希望，有朝一日可以开发出移植组织。它能够向医生报告自身的功能活动，还可以在必要的时侯向组织提供即时反馈，例如把药物释放到皮肤或肺部。利伯说：“我们有机会把细胞系统和电子设备融合在一起。”
（翻译 叶镜安）
Cyborg Tissue Monitors Cells
Nanoelectronic scaffolding supports living tissue.
Megan Scudellari
Researchers at Harvard University have constructed a material that merges nanoscale electronics with biological tissues—a literal mesh of transistors and cells.
The cyborg-like tissue, described online at Nature Materials, supports cell growth while simultaneously monitoring the activities of those cells. It could improve in vitro drug screening by allowing researchers to track how cells in a three-dimensional environment respond to drugs in real time, the authors say. It may also be a first step toward prosthetics that communicate directly with the nervous system, and tissue implants that sense and respond to injury or disease.
Previously, to probe electrical activity of living systems, scientists have developed flat, flexible devices that stretch along the outside of an organ, such as the heart, brain, or skin (see "Making Stretchable Electronics"). But these materials only monitor electrical activity at the surface of a tissue.
The new scaffolding was made by a team of researchersthat includes Bozhi Tian, a 2012 member of Technology Review's TR35 (see "35 Innovators Under 35: Bozhi Tian"); Harvard University chemist Charles Lieber; Daniel Kohane, director of the Laboratory for Biomaterials and Drug Delivery at Boston Children's Hospital; and Robert Langer, a chemical engineer and Institute Professor at MIT. The group set out to design a three-dimensional scaffold that integrates electronics directly into living tissues.
The nanoelectronic scaffolds were made from a thin mesh of metal nanowires, either straight or kinked, dotted with tiny transistors that detect electrical activity. The researchers folded or rolled the mesh into a three-dimensional structure to simulate a piece of tissue or a blood vessel, respectively. The result is a scaffold that is both porous and flexible—not an easy feat for electronics. "These scaffolds are mechanically the softest electronic materials that have ever been made," says Lieber.
The scaffold was then seeded with cells or merged with conventional biomaterials, such as collagen, into hybrid scaffolds. "It shows, from a materials perspective, that you can combine these electronic networks with virtually anything," adds Lieber.
To test the construct's sensing capabilities, the team performed experiments with living cells. They grew neurons in the scaffold, then successfully monitored the cells' firing activity in response to excitatory neurotransmitters; they observed heart cells on one side of the tissue beating in subtly different ways than cells on the other side; and they monitored pH changes on the inside and outside of a simplified blood vessel, made of rolled construct and smooth muscle cells.
Lieber says numerous pharmaceutical companies have already expressed interest in the scaffolds to monitor drug responses in different tissues. "That's the nearest-term application," he says—but not the ultimate goal. Someday, Lieber would like to develop tissue grafts that can report their function to doctors and provide immediate feedback to a tissue when necessary, such as releasing a drug into the skin or lungs. "We have the opportunity to merge electronics with cellular systems," he says.
页:
[1]