The field of optogenetics (biological techniques which entail the use of light to control cells in living tissue, typically neurons, that have been genetically modified to express light-sensitive ion channels) is considered by many people nowadays science fiction material.
But scientists are gathering data that may allow us to do witness things such as a laser-controlled brain or a heart that beats in time to a disco light display and more importantly, create drug-free therapies.
The tools have been gathered from all over the world. There are the Channelrhodopsins – sensory receptors – from algae, which respond to blue light, exciting cells by letting positive charges into the cell. The Halorhodopsins, isolated from extremophile bacteria – bacteria living in extreme conditions – let negative charge into cells in response to yellow light, and shut the excited cell down. A similar trick is performed by Archeorhodopsins, isolated from another extremophile, which pumps positive charge out of the cell in response to yellow light.
Cell biologist Laura Swan says that “by taking parts from human neurotransmitter receptors and these bacterial light-sensitive domains [mentioned above], we can also create more complicated machines in the lab, such as Hylighter, which depresses activity in neurons on exposure to one colour until it is switched off by exposure to a second colour of light”.
What this means in theory is that by combining pulses of blue and yellow light, neurons and muscles can be switched on and off to order. This could lead to therapies whereby excitable cells can be “helped along” without the use of drugs.
Swan suggests these techniques can be used in the treatment of diseases such as Alzheimer’s, although further research into the matter is yet to be done.”For chronic diseases, this may all be worthwhile, but the investment of time and expertise for the procedure will be considerable and is unlikely to change much as the technology advances. It’s clear we have a long way to go, but we may yet have our brains tripping the light fantastic”, she concludes.