考研英语阅读篇章: 功能性3D类脑组织诞生

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    考研英语阅读篇章: 功能性3D类脑组织诞生
    Bioengineers have created three-dimensional brain-like tissue that
functions like and has structural features similar to tissue in the rat brain
and that can be kept alive in the lab for more than two months. As a first
demonstration of its potential, researchers used the brain-like tissue to study
chemical and electrical changes that occur immediately following traumatic brain
injury and, in a separate experiment, changes that occur in response to a drug.
The tissue could provide a superior model for studying normal brain function as
well as injury and disease, and could assist in the development of new
treatments for brain dysfunction(功能紊乱).
    The brain-like tissue was developed at the Tissue Engineering Resource
Center at Tufts University, Boston, which is funded by the National Institute of
Biomedical Imaging and Bioengineering (NIBIB) to establish innovative
biomaterials and tissue engineering models. David Kaplan, Ph.D., Stern Family
Professor of Engineering at Tufts University is director of the center and led
the research efforts to develop the tissue.
    Currently, scientists grow neurons in petri dishes(培养皿) to study their
behavior in a controllable environment. Yet neurons grown in two dimensions are
unable to replicate the complex structural organization of brain tissue, which
consists of segregated regions of grey and white matter. In the brain, grey
matter is comprised primarily of neuron cell bodies, while white matter is made
up of bundles of axons, which are the projections neurons send out to connect
with one another. Because brain injuries and diseases often affect these areas
differently, models are needed that exhibit grey and white matter
compartmentalization.
    Recently, tissue engineers have attempted to grow neurons in 3D gel
environments, where they can freely establish connections in all directions. Yet
these gel-based tissue models don't live long and fail to yield robust,
tissue-level function. This is because the extracellular environment is a
complex matrix in which local signals establish different neighborhoods that
encourage distinct cell growth and/or development and function. Simply providing
the space for neurons to grow in three dimensions is not sufficient.