Nanoporous Particles Deliver Novel Molecular Therapies to Tumors

Nanoporous Particles Deliver Novel Molecular Therapies to Tumors
(PhysOrg.com) — Using nanoporous silicon particles, two teams of investigators have created drug delivery vehicles capable of ferrying labile molecular therapies deep into the body. Both groups believe their new drug delivery vehicles create new opportunities for developing innovative anticancer therapies.

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Nanocomposite Said To Boost Lithium Batteries By 5X

Nanocomposites aim to boost the capacity of lithium ion batteries by five-times by hanging nanometer-sized silicon particles on trees of carbon black that self-assemble into porous micron-sized spheres, which increase an electrode’s surface area with interconnected internal channels.

High-performance lithium ion batteries today use anodes made from carbon (graphite). Silicon has been proposed as a substitute for graphite since it offers a theoretical improvement of 10-times in capacity over graphite, but so far prototypes have proven too unstable for creating lithium batteries with a long lifetime, according to professor Gleb Yushin at the Georgia Institute of Technology.

The problem, according to Yushin, is that silicon particles crack when they are formed at the same granularity of graphite particles—about 15 to 20 microns. The new nanocomposite material solves that problem by hanging 30 nanometer sized silicon particles on trees of carbon black which then self-assemble into porous spheres about 10-to-30 microns in diameter. The resulting electrode remains stable due to the durable carbon-superstructure that prevents cracking, but benefits from the increased surface area afforded by the smaller silicon nanoparticles.

Common chemical vapor deposition processes allow the new hybrid silicon-carbon electrodes to be mass produced economically, according to Yushin. He also claimes that because the tiny silicon nanoparticles are permanently attached to the micron-sized carbon black trees, they avoid the health hazards of processes that require handling of nanoscale particles.

So far Georgia Tech has fabricated experimental anode electrodes, which it is testing for use in standard manufacturing processes for lithium batteries. Their prototype has survived over one hundred recharge cycles without any degradation, leading the researchers to predict they will last for thousands of recharges.

Besides Yushin, other Georgia Tech researchers involved in the project include Alexandre Magasinki, Patrick Dixon, Benjamin Hertzberg and Alexander Alexeev, along with Alexander Kvit from the University of Wisconsin-Madison, Igor Luzinov from Clemson University, and Jorge Ayala from Superior Graphite (Chicago).

Funding was provided by a Small Business Innovation Research (SBIR) grant from the National Aeronautics and Space Administration (NASA) to Superior Graphite and Streamline Nanotechnologies, Inc.

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Charging Ahead With Nanotechnology

With all of the technology that is being continuously introduced and used, it would only seem logical in our quest for a green world to apply some of the renewable energy efforts to this spectrum. That is exactly what some scientists are looking into with their research on how nanotechnology can be used with lithium batteries.

According to Science News, a report that will be published in International Journal of Nanomanufacturing asserts that “carbon nanotubes can prevent such batteries from losing their charge capacity over time.” The batteries they are speaking of are the lithium-based batteries that are found in commonly used devices such as MP3 players, laptop computers, and cell phones.

As any of us who partake of these various technologies are quite aware of, with continued use, the battery power just seems to lose its life. As the news story reports, elements such as hot and cold temperatures help this reduction process along even more. Scientists have been researching this degradation process for awhile, and have looked into silicon to replace the universally used lithium-ion batteries. However, due to the fast rate that silicon also degrades, they have had to search even further.

This is where nanotechnology comes into play. As Science News states, “Shengyang’s Hui-Ming Cheng and colleagues have turned to carbon nanotubes (CNTs) to help them use silicon (Si) as the battery anode but avoid the problem of large volume change during alloying and de-alloying.” By introducing the carbon nanotubes to the silicon, they seem to be solving some of the problems that previously existed.

The whole process is quite amazing. “The researchers grew carbon nanotubes on the surface of tiny particles of silicon using a technique known as chemical vapor deposition in which a carbon-containing vapor decomposes and then condenses on the surface of the silicon particles forming the nanoscopic tubes. They then coated these particles with carbon released from sugar at a high temperature in a vacuum. A separate batch of silicon particles produced using sugar but without the CNTs was also prepared.”

The scientists used these two diverse batches and compared them. What they found was remarkable – the batch using the carbon produced a discharge capacity twice that of the one which only contained the silicon particles.

There seems to be many reasons that have prompted research into better material used to create batteries. Reports of fires found to be ignited by lithium-ion batteries, although rare, seem to have caused much attention to be placed on safer materials. The general complaint many have regarding the increased reduction of device batteries after continued use is likely another reason that prompted the research. Whatever the likely combination was, this new research could be monumental in how users of technological devices power up their gadgets.

Nanotechnology is not the only material researchers are using in their quest for a better battery, but it does seem to be one of the options that show much promise.