Getting Touchy-Feely with Cilia
A cilium is a subunit of a cell that sticks out like a hair. They are quite common in animals–a human has cilia on almost every cell, and cilium failures can result in various diseases.
Cilia can act as sensors, for instance responding to light or chemicals or temperature. Some cilia can also wave around in patterns of synchronized movement. This movement causes locomotion, either of nearby stuff (such as cells in human lungs raking mucus), or of the parent body itself (as in the case of certain microscopic organisms).
Writer Sally Pobojewski describes cilia’s usefulness:
“Thanks to cilia, you can see the words on this page, smell fresh coffee brewing in the morning and hear birds chirping outside the window. Cilia regulate the growth of kidney cells and control how an embryo develops. They sweep particles and mucus out of the respiratory tract, nudge eggs down fallopian tubes, and help neurons in the brain grow new connections.”
Of course, nature also has arrays of cilium-like structures at scales larger than single cells, for instance hair and the various slender protuberances in flowers.
A recent report describes a new type of material with cilia-like protuberances that was developed by Fang Liu, Dhanya Ramachandran, and Marek W. Urban at the University of Southern Mississippi. The artificial cilia on this copolymer film can change shape and color in response to various electromagnetic, chemical, and thermal stimuli. This material, especially if it advances, could be used for new types of sensors and actuators.
Artificial cilia are also potentially useful at a macro scale, for instance Super Cilia Skin designed by Hayes Raffle, Mitchell Joachim, and James Tichenor. Super Cilia Skin is a haptic membrane for human-computer interaction. Humans can move the cilia with their hands, which could be an interesting tactile experience in itself when combined with a computer system. Each cilium can move on its own as well for feedback to the user, either by feel or as a visual display. Although the killer app for Super Cilia Skin has not surfaced yet, it also has potential as an exotic energy harnessing material for building exteriors.
Another artificial cilia example is designer Giles Miller’s Miranda Surface Tiles. These silicon tiles have thousands of plastic hairs and could at the very least be used as interactive decorations.
There are some provocative fictional uses of cilia-like structures. For instance, in Avatar, the lifeforms of Pandora have wiggling fibers called queues (or tswin in the Na’vi language). When two queues are connected, they establish a neural bond (_tsaheylu_) between the two organisms.
Perhaps soon we will be making artificial cilia that can enable interfaces as good as in nature and as informationally complex as in Avatar.