Quantum dots
http://nanodot.org/article.pl?sid=02/01/02/1653221
According to the article, by selectively coding peptides that coated quantum dots, University of Texas scientists precisely controlled the spacing of hundreds of quantum dots on the surface of the living neurons. The cadmium sulfide contacts act as photodetectors, allowing researchers to communicate with the cells using precise wavelengths of light. Taken to the logical extreme, biologists could remotely control any neural function by activating select neurons. One idea is to put a quantum dot right next to a protein channel — one that opens and closes — allowing ions to go in and out, and basically control the ion exchange, which in turn controls action potentials [neuron 'firing'].
http://www.eetimes.com/story/technology/OEG20011204S0068
By using the molecular-recognition capabilities of living cells, scientists have made selective electrical contacts to neurons. The cadmium sulfide contacts act as photodetectors, allowing researchers to communicate with the cells using precise wavelengths of light.
We can take peptide molecules that have very specific protein sequences and put them into the actual semiconductor material, which then very specifically binds to particular locations on cell surfaces."
Scientists had already attached a variety of objects to cells using biorecognition, such as fluorescent dyes, enzymes and radioactive labels, but Schmidt said her group is the world's first to intentionally interface with neurons electrically.
"What's unique about it is that we can do this on a very very small-length scale — that we can really pull the semiconductor material directly to the cell surface using these very short [roughly 3-nm] peptide sequences," she said. "We can distribute them to different parts of the cell depending on what we want to trigger."
In this new biological application, attaching quantum dots directly to cells eliminates the need for external electrodes. The procedure is entirely non-invasive, similar to the use of fluorescent dyes to mark cells. And since molecular recognition is used, it is a "smart" technology that can pick precisely which capability will be controlled on each neuron to which a quantum dot is attached. Taken to the logical extreme, biologists could remotely control any neural function by activating select neurons.
"Presumably, in the future we will be able to turn on an ion channel or turn off something else," said Schmidt. "We could have highly regulated activity in the neuron. . . . One idea is to put a quantum dot right next to a protein channel — one that opens and closes — allowing ions to go in and out, and basically control the ion exchange, which in turn controls action potentials [neuron 'firing']. These are the electrical signals with which the neuron interacts with the brain."
http://www.pcmag.com/article2/0,1895,1165553,00.asp?rsDis=Accelerated_Living-Page002-10163 //Nanobots
Another technology that will greatly enhance the realism of virtual reality is nanobots: miniature robots the size of blood cells that travel through the capillaries of our brains and communicate with biological neurons. These nanobots might be injected or even swallowed.
Scientists at the Max Planck Institute have already demonstrated electronic-based neuron transistors that can control the movement of a live leech from a computer. They can detect the firing of a nearby neuron, cause it to fire, or suppress a neuron from firing—all of which amounts to two-way communication between neurons and neuron transistors.
Today, our brains are relatively fixed in design. Although we do add patterns of interneuronal connections and neurotransmitter concentrations as a normal part of the learning process, the capacity of the human brain is highly constrained—and restricted to a mere hundred trillion connections. But because the nanobots will communicate with each other—over a wireless LAN—they could create any set of new neural connections, break existing connections (by suppressing neural firing), or create hybrid biological/nonbiological networks.
Using nanobots as brain extenders will be a significant improvement over today's surgically installed neural implants. And brain implants based on massively distributed intelligent nanobots will ultimately expand our memories by adding trillions of new connections, thereby vastly improving all of our sensory, pattern recognition, and cognitive abilities.
Nanobots will also incorporate all of the senses by taking up positions in close physical proximity to the interneuronal connections coming from all of our sensory inputs (eyes, ears, skin). The nanobots will be programmable through software downloaded from the Web and will be able to change their configurations. They can be directed to leave, so the process is easily reversible.
In addition, these new virtual shared environments could include emotional overlays, since the nanobots will be able to trigger the neurological correlates of emotions, sexual pleasure, and other sensory experiences and reactions.
When we want to experience "real" reality, the nanobots just stay in position (in our capillaries) and do nothing. If we want to enter virtual reality, they suppress all of the inputs coming from the real senses and replace them with signals appropriate for the virtual environment. Our brains could decide to cause our muscles and limbs to move normally, but the nanobots would intercept the inter-neuronal signals to keep our real limbs from moving and instead cause our virtual limbs to move appropriately.
