Biomedical Engineering Reference
In-Depth Information
ability to isolate single cells and grow them
in vitro
developed
(Landecker, 2007). This new-found capacity to isolate single tissues,
grow them into colonies using feeder solutions and freeze them until
needed were significant achievements on the path to practices like
assisted reproduction and stem cell research (Landecker, 2007: 151).
While this brief history of tissue culture highlights some crucial
moments in the development of contemporary practice, it does not
account for the origins of ideas about stem cells. Another analysis
(Cooper, 2003) traces how ideas about embryogenesis and
regeneration arose in the history of cell culture, with an interesting
elucidation of where the original impetus for thinking of human
tissues as containing cells that may be isolated and used for
regeneration came about. In essence, questions about regeneration
and the applications of observable regeneration to human tissue
growth started long before Harrison's technical achievements at
growing tissues
in vitro
(Cooper, 2003).
Late seventeenth-century debates between preformationists and
epigeneticists are one possible starting point for thinking about the
regenerative capacities of embryonic cells (Cooper, 2003).
Preformationism was a popular theory of human development in the
seventeenth century, with preformationists believing that all of the
components of the fully grown human were contained in the sex cells - a
homunculus - ready to emerge fully formed (Cooper, 2003). Yet this
form of explanation of human development failed to explain evidence
from the natural world of spontaneous regeneration in some
organisms (Cooper, 2003). Experiments in 1744 with the
Hydra
plant - a freshwater plant that was demonstrated to infinitely regrow
every time a piece of it was cut off - drew attention to the possible
explanation that each piece of the
Hydra
must contain a fully formed
homunculus, ready to spring into action when required (Cooper,
2003). It is not difficult to see here the beginnings of a linkage
between the tissue-culturing experiments outlined above and the idea
of an in-built 'homunculus' ready to develop when required.
The epigeneticists' response to the claims of the preformationists
was to suggest that there is at work in all living material a life force
or principle of self-organization that allows unformed matter
to be shaped as desired when needed by the individual organism
