Molecular memory is regarded by some as the next big evolution in memory storage, looking to supplant Dynamic random access memory (DRAM) as a cheaper option for high-speed computing. Molecular memory relies on the existence of certain bistable molecules which may be induced to switch between states based on electric input. Typically this bistability relies on oxidation and reduction reactions in which an electron is either donated or received by the molecule. These reactions are dependent on the electrical environment around each molecule, and new technology promises to ease and standardize the control of such environments.
A collaboration between labs in UCLA and the California Institute of Technology has recently published an article in Nature decribing a 160-kilobit memory device using these molecular switches in combination with nanowire meshes to create controllable electronic environments. Nanowires are similar to nanotubes, except that they may consist of materials other than carbon - in this case Silicon and Titanium - that may result in unique conductive properties. In this device, the silicon and titanium nanowires cross eachother in a checkerboard pattern (see figure) with bistable molecules at each intersection. Manipulation of each nanowire controls the state of each switch and serves as a miniscule bit of memory on the order of 100 billion bits per square centimeter.
Nanotubes consist of a lattice of carbon atoms curved into a cylinder (see figure) of about 1-2 nanometers in diameter. They may be produced via arc-discharge methods to make multi-walled nanotubes (MWNT) or via laser ablation or chemical vapor deposition to make single-walled carbon nanotubes (SWNT). See this site on nanotube production for a description of these methods.
Nanotubes are a very popular aspect of nanotechnology because of the interesting features that they possess. SWNTs have strengths determined to be 50-100 times that of steel and with an elasticity on the order of terrapascals, which is among the most elastic materials on Earth. Moreover, nanotubes have a higher thermal conductivity than any natural material and 100 times the electrical conductivity of copper, the most commonly used conductor in electronics. Nanotubes have a density half that of aluminum and, to top it off, are stable of temperatures exceeding 2700 degrees C.ApplicationsOne of the mort commonly sited applications of carbon nanotubes is for use in electronics as nano-sized transistors. Their size and manipulatability in the nano levels are promising as we attempt to keep up with Moore's law to create smaller and smaller chips. Moreover, the potential of nanotubes for superconductivity drastically reduces the heat waste in transmission that creates such a problem in today's computers. Though the technology is still in its relative infancy, nanotubes look to be the next revolution in chip-making that will allow us to keep up with the breathtaking progression that Moore's law predicts.Their amazing mechanical properties give nanotubes many other potential applications as well. For instance, nanotubes are being used in bikes in the Tour de France and being researched as materials for use in space by NASA. As production of carbon nanotubes becomes cheaper and more precise, their applications will surely multiply.
OverviewStarpharma Holdings Ltd. claims to be the world leader in using dendimer-based nanotechnology for pharmaceutical development. Starpharma was founded in 1996 out of the Biomolecular Research Institute (BRI) and is currently traded on the Australian Stock Exchange (ASX). The company specializes in using dendrimer technology to create pharmaceuticals aiding in the prevention of STDs, including herpes and HIV. Starpharma has received over $20M in government grants (NIH) and recently acquired Dendritic Nanotechnologies (DNT) in order to strengthen research into further denrimer applications. Starpharma has a market cap of around $89M.Starpharma.comProductsVivaGelTM - This gel-based STD preventative is the most advanced of Starpharma's pharmaceuticals. VivaGel has successfully tested in Phase I clinical trials and is currently testing in the US, Australia, and Kenya. Based on its potentially critical role in preventing STDs, the FDA has granted VivaGel Fast Track status through its regulatory process.News10.10.2006- Starpharma acquired DNT for approximitely $14M. The acquisition provides Starpharma with strengthened control over primary dendrimer development and gives Starpharma ownership over additional dendrimer patents, making Starpharma the leader in holding such patents. Starpharma had previously held a 33% stake in DNT.1.9.2006- VivaGel received Fast Track status from the FDA.10.3.2005- Starpharma received $20M from the NIH to further develop VivaGel.4.1.2005- Starpharma received AUD$5.7M from the Australian government to pursue dendrimer-based pharmaceutical development.
Dendrimers are carbon-based polymers consisting of several branched monomers, called dendrons, surrounding a central core (see figure). Dendrimers consist of the core, the branches, and the end groups that exist at the end of the outermost monomers.
The properties of dendrimers can be altered by several means. First, the size of the dendrimers created is highly manipulatable. Dendrimers are produced in iterative sequences of reaction steps, with each iteration creating one additional layer of monomer branches. Each reaction effectively doubles the molecular weight of the dendrimer as well as the amount of active end groups at the edge of the dendrimer, allowing for the creation of very well defined structures. The end groups themselves also play an important role in the functionality of dendrimers. By altering these "active" groups, one may control the way in which dendrimers react with their immediate environment.
There are many potential applications of dendrimers in medicine. Due to their solubility in water, dendrimers may be used as nano-sized capsules through which to transport insoluble drugs in the human body. Dendrimers may essentially be used as highly manipulative biological coats designed to allow drugs to enter target cells without risking degradation or rejection. This coat function may also be used to deliver insoluble imaging agents to cells of interest for fluorescent imaging. Dendimers may also be made into insoluble scaffolds when specific cross-linking groups are used as the end groups. These insoluble scaffolds may be used to repair damaged tissue.
Dendimers are interesting because of the vast amount of potential functions that they offer. Simple alterations in dendrimer shape or end group composition can have profound effects on the properties of that dendrimer. Morover, the simple carbon makeup of these dendimers make them easily biodegradable and safe for medical use in humans. For a comprehensive review of dendimer properties and functions, see this article published in Nature Biotechnology.
Overview
Nanospectra is a private company founded by Dr. Jennifer West in 2002 in Houston, TX and largely funded from government grants. The company specializes in using gold-coated nanoshells to absorb near-IR light and destroy cancer tumor cells in a therapy dubbed Aurolase TM therapy. This method is quicker and more specific than chemotherapy and results in a substantial reduction of side effects. Aurolase TM therapy is currently in Phase I of clinical testing and is currently seeking FDA permission to enter Phase II clinical testing in human patients with head and neck cancer. Nanospectra.com
Recent News
11.02.2006- Nanospetra sold $1.7M of series A preferred stock in order to fund pilot trials for Phase II of the Aurolase TM therapy.
Collaborations
2007- Nanospectra received $1.25M from the Texas Emerging Technologies Fund (TETF) and $500K from the National Science foundation (NSF) to continue development and testing of the Aurolase TM cancer therapy.2005- Nanospectra received $392K from the NSF for cancer research and $750K from the US Air Force to research nanoshell applications in detecting harmful biological and chemical agents.
2004- Nanospectra received $428K from the National Institute of Health (NIH) to research nanoshell detection of plaques related to Alzheimer's disease and $2M from the NIST ATP award for cancer treatment.
