I just came across an article in http://www.medicalnewstoday.com which goes over the use of
use of gold nanoparticles carrying drug molecules to target and treat cancer cells, something that was already presented in this post last February. This confirms that scientist keep foreseeing nanotechnology as new treatment against cancer, which might also replace radiation, chemotherapy, etc... in a near future.
In the study presented, the researchers used a single-stranded DNA aptamer called AS1411 which does two jobs. The first is to bind with the "shuttle" protein nucleolin, which is over-expressed in cancer cells and present inside the cell and on the cell surface. The second job is, once it is released from the nanostar, is to act as the drug itself. The results were quite more than satisfactory, as scientist observed death and decline in cancer cell population, exactly the intended objective.
In my last post, I discussed about what we can expect from developments in cochlear implants, a technology that has been with us for more than 30 years. As it was briefly explained, cochlear implants stimulate the cochlea by means of electrodes, making possible for the brain to interpret this information as sound. In this way, I have been thinking if it wouldn't be possible to do the same for blind people. A quick search on google and... voila, I found that we already have what it is called "a retinal stimulator" or "artifical retina" implant.
Some history I found about it: In the mid-1980s, the neuroophthalmologist Joseph Rizzo III was researching retinal transplants to restore blind people's vision. One day, removing a lab animal's retina, a tissue-thin membrane that lines the back of the eyeball's interior, he made a tremendous discovery. "The moment I made the cut, I said to myself, 'What in the hell are you doing?'" Rizzo recounts. He realized he was cutting nerve connections that are actually spared in many forms of blindness. The retina's light-sensing cells (photoreceptors, or rods and cones) die off in retinitis pigmentosa and age-related macular degeneration, which affect millions worldwide; but the nearby neurons that ferry the signals from those cells to the brain remain intact.
So Rizzo conceived what he called "a retinal prosthesis", a device intended to bypass the damaged eye structure. This has evolved to what we call nowadays and artificial retine which works as follows: a miniature camera mounted in eyeglasses captures images and wirelessly sends the information to a microprocessor (worn on a belt) that converts the data to an electronic signal and transmits it to a receiver on the eye. The receiver sends the signals through a tiny, thin cable to the microelectrode array, stimulating it to emit pulses. The artificial retina device thus bypasses the damaged photoreceptor cells and transmits electrical signals directly to the retina’s remaining viable cells. The pulses travel to the optic nerve and, ultimately, to the brain, which perceives patterns of light and dark spots corresponding to the electrodes stimulated. Patients learn to interpret these visual patterns. A lot of research and effort has been put in this technology since then and finally last year the first such device was approved in Europe for commercialization: The Argus II Retinal Prosthesis System by Second Sight.
But this shouldn't be perceived as making possible for blind people to see. In the same way that cochlear implants only partially restore hearing, the artificial retinal is not intended to fully restore vision, but to artificially provide electrical signals that the brain can interpret as shapes. Research is made towards increasing the number of electrodes thus increasing the "reslution" of the images that can be perceived. The ultimate goal is to design a device with hundreds to more than a thousand microelectrodes (DOE Artificial Retina Project). This resolution will help restore limited vision that enables reading, unaided mobility, and facial recognition. Also, some research goes towards the use of human tissue to improve the communication between biological tissues and artificial sensors. Researchers in Italy have now reported the functional interfacing of an organic semiconductor with a network of cultured primary neurons. Their novel approach represents a new tool for neural active interfacing, which is a simpler alternative to the existing and widely used neuron optogenetic photostimulation techniques, and avoids gene transfer, which is potentially hazardous. In words of one of the researches, Guglielmo Lanzani, "This new approach to the optical stimulation of neurons may stimulate further work towards the development of an artificial retina based on organic materials."
