Finnish researchers have designed tiny nano-particles which can deliver a specific drug to cells of the inner ear. Once brought into position, this drug helps to repair damaged ear cells. As a result people with hearing loss have experienced a significant improvement of their condition.
In the European Commission-funded project NANOEAR, scientists from several countries in Europe are studying where different nanoparticles go within the inner ear and if these nanoparticles could be harmful or useful in therapeutics. They are currently testing eight nanoparticle classes, for example, biodegradable liposomes, micelles and lipid-core nanocapsules, regarding their delivery of genes, peptides, corticosteroids, siRNA and shRNA. Since nanoparticles also have properties that separate them, the researchers need to find the best carrier for each drug.
The project’s researchers are working on nanoparticles targeted towards hair cells, neurons and supporting cells. They have identified fundamental peptides helping the nanoparticles to avoid being trapped and dysfunctionalized by the lysosomal enzymes in the cell’s endosome system, so the nanoparticles are able to deliver the therapeutic drugs to their targets.
Nanodiamonds enable progress with Retina Prothesis
In France, nanotechnology is used to help blind people with a new generation of artificial retinal prostheses. Scientists have created synthetic diamond crystals and implant them on the retina of the patient. The diamond can stimulate the retina and compensate the damaged photoreceptors. The results are impressive, as Serge Picaud from the Inserm Institut de la Vision in Paris points out: “A patient who was blind can now see letters and read small words. That’s pretty exceptional!”
Scientists at the University of Tübingen in Germany have recently developed another subretinal prosthesis and tested it on patients. They have managed to show, for the first time, that micro-electrode arrays containing 1500 photodiodes can give previously blind patients a meaningful and detailed visual perception. Through a corresponding pattern of 38 x 40 pixels produced by the chip, one patients could for example read large letters as complete words, localize and approach persons freely and describe different sorts of fruit.
While another team of researchers from Moorfields Eye Hospital, Manchester Royal Eye Hospital, Quinze-Vingts, Second Sight, Retina Foundation Southwest and Johns Hopkins University, has shown for the first time that a large group of blind patients fitted with a retinal prosthesis can identify letters successfully. The patients used the Argus II Retinal Prosthesis System, but the researchers are working on the third model, increasing the number of electrodes from 60 to 240.
Researchers connected to the European Commission-funded project DREAMS are instead working on new types of nanotransducers, electric devices converting energy from one form to another, based on artificial nanocystalline diamond. The reasons for using diamond to coat the prosthesis are that this semiconductor show stability, biocompatibility and allow for reduced stimulation currents to improve the resolution from 60 pixels, where only shapes and colors can be seen, to 1000 pixels. The scientists have tested the tiny prosthesis on retinal cells to see that it can replace the photoreceptors and U.S. colleagues have shown that a similar implant in humans can function. However, no clinical trials using the nanodiamond approach have been conducted.