Stimulating nerve impulses with nanoparticles

US researchers have successfully built the first hybrid bio-nano device that allows electrical connections between nerve cells and photovoltaic nanoparticle membrane membranes. The discovery paved the way for the application of the uniform properties of nanoparticles to a range of devices that probe nerve impulse signals by stimulating light, including the ability to create artificial retinas. based on nanoparticles (New results published in Nanoletters 7 (2007) 513)

Currently, nanoparticles have begun to be used in a wide range of biomedical areas such as imaging, sensor, probe, AND analysis and cancer treatment. Recently, scientists have begun to pay attention to the ability to pair nanomaterials (eg nanotubes, nanowires) with neurons. And recently, Nicholas Kotov (University of Michigan) and colleagues at the University of Texas Medical School, Galveston (UTMB), successfully paired the photovoltaic nanoparticles with a nerve cell for the first time.

The researchers created this result by developing a process to build a super-thin sandwich system on the surface of a glass substrate . The first layer is the layer of semiconductor nanoparticles Hg-Te (Mercury - Telua) and the second layer is the positively charged polymer layer called PDDA (Poly DiallylDimethylAmmonium). The third layer is a layer of clay and coated with a layer of biocompatible (amino acid) with structure and finally a neuronal layer is implanted on top.

When light hits the Hg-Te membrane, they pop out electrons and move to the PPDA layer. When electricity flows to the neuron membrane at the top, they eliminate cell polarization to a point where it is " burned " and produces nerve impulses to nerve cells.

Researchers had previously allowed light to pass through nerve cells using Silicon, but the nanomaterials gave stronger activity and created less stability."We can completely adjust the electrical characteristics of nanoparticle films to create properties such as color sensitivity, and different stimuli, which are the properties you want if you want to create Artificial retina, one of the subject's biggest goals, " - Todd Pappas, the lead author of the paper published in Nano Letters - " You can't do that with Silicon. Also, Silicon is a block material - Si components have less size compatibility with cells ".

Photograph of a neuron growing on the material

Researchers say that although an artificial retina that does not grow reality is still something other than research results, research results can be used in many less complex applications. more trash. That is to include ways to connect artificial limbs and prostheses, and new tools for photography and diagnosis."The great thing about this achievement is that these materials can be activated remotely without using a connection cord. All you need to do is how to bring light to the material" - Massould Motamedi, director of the Biomedical Engineering Center, co-author of the work, said: "I feel that more and more nano tools will lead to more medical and biological fields. new application, which is even harder to imagine ".

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