Gecko foot design—could it lead to a real ‘spiderman’?
by Jonathan Sarfati
In Creation, we reported on how a gecko can stick to almost any surface,
so it can even run upside down on a ceiling of polished glass.1 This is due to the way tiny chemical forces are exploited
by tiny hairs called setae, about 1/10 of a millimetre long
and packed 5,000 per square millimetre (three million per square inch). The end
of each seta has about 400–1,000 branches ending in a spatula-like structure
about 0.2–0.5 microns—less than 1/50,000 of an
inch—long (a micron is 1/1,000 of a millimetre). This
is an amazingly fine structure that the researchers said was ‘beyond the limits
of human technology’.2
But this is not enough—it would do the gecko no good to have this amazing
foot if it could only stick—it must also unstick quickly. The gecko manages
this with the ‘unusually complex behaviour’2/a>
of uncurling its toes when attaching, and unpeeling while detaching.
Since man was created in God’s image, we should not be too surprised that
man can also imitate God’s creativity to some degree.
Engineer Metin Sitti, of Carnegie Mellon University in Pittsburgh, USA, has managed
to duplicate the gecko foot surface structure to some extent.3 He used a very fine nanoprobe and an electron microscope
to make a tiny wax mould for a resin, which set to form artificial hairs. Dr. Sitti
points out that the shape and orientation of the hairs is important for their function.
His artificial hairs are not yet strong enough to support the weight of a human,
but the researchers are continually improving their technology. He aims to makes
robots for planetary exploration that could climb over any surface.3
Dr. André Geim, of the University of Manchester, leading a team of scientists
from the UK and Russia, prepared a self-cleaning adhesive tape modelled on the gecko’s
foot.4 Their tape,5 with a contact area of only 0.5 cm2 with glass,
could bear a load of more than 100 grams.6
However, the tape is not durable enough to attach and detach more than a few times,
unlike the real gecko. The researchers proposed using a more durable material—that
which the real ones are made of, keratin.6
If they did, then gloves and shoes made of this might enable a real spiderman (or
should that be geckoman?) to climb up walls of almost any surface. However, this
would require training, to match the gecko’s movement patterns, and one must
wonder whether humans could manage this. And a planet-exploring robot would need
this to be programmed into it. So far, the artificial gecko skin seems good only
for attaching things in place.
Once more, we see that the intelligence that went into the artificial setae (hairs)
and tape is a good lesson on the much greater intelligence of the One who designed
the original. Despite their ingenuity, the researchers cannot equal the original
design, which evolutionists believe arose by time, chance and natural selection.
References and notes
- Sarfati, J.,
Great gecko glue? Creation 23(1):54–55, 2000.
Return to text.
- Autumn, K. et al., Adhesive force of a single gecko foot
hair, Nature 405(6787):681–685, 8 June 2000; perspective
by Gee, H., Gripping feat, same issue, p. 631. Return to text.
- Graham-Rowe, D., Fancy a walk on the ceiling? New Scientist
178(2395):15, 17 May 2003. Return to text.
- Geim, A. et al. Microfabricated adhesive mimicking gecko
foot-hair, Nature Materials 2:461–463, 2003.
Return to text.
- The tape had fibres 2 microns long, with a diameter of around 0.5
microns and spaced 1.6 microns apart, on a film of polyimide 5 microns thick. Dr.
Geim and his colleagues used the advanced nanotechnology methods of electron-beam
lithography and dry etching in oxygen plasma. Return to text.
- Kalaugher, L., ‘Gecko tape’ sticks with polymer fibres,
Physics Web, <physicsweb.org/article/news/7/6/4>, 5 June 2003. Return to text.
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