09 September 2013

Therapeutic nanoparticles themselves move to the cracks in the bone

Broken bones attract healing nanoparticles

ChemPort.Ru based on materials from Chemistry World: Cracked bones attract healing nanoparticlesAmerican scientists used drug-carrying nanoparticles to recognize and heal microcracks in human bones.

The developed system is based on the use of ions seeping from cracks in the bone, which allows you to pull the particles to the damaged areas.

The new system can provide better targeted treatment of such conditions of the body as, for example, osteoporosis, or can find application in the development of self-healing materials.

The patterns underlying the developed methodology are well known. Ayusman Sen, one of the scientists involved in this project from the University of Pennsylvania in the USA, explains that if the fresh, unventilated surface of a mineral is exposed to water, it will dissolve to some extent, which will lead to the formation of ions. If there is an anion and a cation and one of them diffuses faster than the other, then an electric field is created. Then it becomes possible to use this field to move charged particles in a certain direction.

Sen and colleagues, studying the effect of ion diffusion in various tissues, found that they are especially strong in bone tissue. A crack in the bone creates a local electric field because negatively charged hydroxide ions leave the crack faster than larger, positively charged calcium ions. Negatively charged nanoparticles move along a positive charge gradient, so that they move in the direction of the crack.

Sen's group showed that the observed phenomenon can be used to detect and heal damaged areas of bone. To recreate these bone-healing nanoparticles, they prepared negatively charged sodium alendronate (sodium alendronate), which is biologically compatible with an oral medication commonly used to treat osteoporosis. Samples of human bone with a fresh fracture were exposed to nanoparticles in vitro, and a fluorescent image showed that the particles were concentrated at the sites of bone fractures.

Sen notes that this method allows you to quickly deliver the medicine exactly where it is needed. As a rule, a drug is taken to get to where it needs to be through simple diffusion. According to Sen, the new approach is a more effective way to "point" at the designated place. Sen emphasizes that there are still many tasks to be solved before this technique can be launched for use in clinical practice. The next step of the scientists will be an attempt to test the new system in an environment more reminiscent of a living system – where there is competition with ion gradients.

Stephen Ebbens from the University of Sheffield in the UK, who is also working on autonomously moving nanodevices, says that the really remarkable thing about this work is that it demonstrates steps towards a potentially practical application.

Ebbens agrees that researchers still have a long way to go before practical application in medicine, but at the same time says that this method of controlling nanoparticles could be used to create self-healing tissues or to control components of microcapillary devices. Ebbens adds that anything that causes this kind of ion gradient can lead to this phenomenon. Therefore, Ebbens believes that applications using similar mechanisms outside the body could be a much easier launching pad for their implementation.

Article by Vinita Yadav et al. Bone-Crack Detection, Targeting, and Repair Using Ion Gradients is published in the electronic version of the journal Angewandte Chemie.

Portal "Eternal youth" http://vechnayamolodost.ru09.09.2013

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