Sunday, August 10, 2008

Nanosilver Bullet Kills HIV

The first of many technological miracles?

In a groundbreaking study, the Journal of Nanotechnology has published a study that found silver nanoparticles kills HIV-1 and is likely to kill virtually any other virus. The study, which was conducted by the University of Texas and Mexico University, is the first medical study to ever explore the benefits of silver nanoparticles, according to Physorg.

During the study, researchers used three different methods of limiting the size of the silver nanoparticles by using capping agents. The capping agents were foamy carbon, poly (PVP), and bovine serum albumin (BSA). The particles ranged in size from 1 to 10 nanometers depending on the method of capping. After incubating the HIV-1 virus at 37 C, the silver particles killed 100% of the virus within 3 hours for all three methods. The scientists believe that the silver particles bonded through glycoprotein knobs on the virus with spacing of about 22 nanometers in length.

While further research is needed, researchers are optimistic that nanological silver may be the silver bullet to kill viruses. The researchers in the study said that they had already begin experiments using silver nanoparticles to kill what is known as the super bug (Methicillin resistant staphylococcus aureus). Already used as a topical antibiotic in the medical industry, silver may now come under consideration as an alternative to drugs when it comes to fighting previously untreatable viruses such as the Tamiflu resistant avian flu.

In the first-ever study of metal nanoparticles' interaction with HIV-1, silver nanoparticles of sizes 1-10nm attached to HIV-1 and prevented the virus from bonding to host cells. The study, published in the Journal of Nanotechnology, was a joint project between the University of Texas, Austin and Mexico Univeristy, Nuevo Leon.

"Our article opens an important avenue for research," said Miguel Jose Yacaman, from University of Texas, Department of Engineering and one of the study's authors.

In this study, scientists mixed silver nanoparticles with three different capping agents: foamy carbon, poly (PVP), and bovine serum albumin (BSA)."Not using a capping agent could result in the synthesis of big crystals instead of nanocrystals," explained Yacaman.

Transmission electron microscopy (TEM) showed the silver nanoparticles in the foamy carbon matrix were joined together, but an ultrasonic bath in deionized water released a significant number of nanoparticles. These nanoparticles were of size 16.19 (+-8.69)nm and had the greatest variety of shapes, such as icosahedral, decahedral, and elongated.

"Because of the synthesis procedure, the foamy carbon-coated naoparticles are more likely to have broad shape distribution," said Yacaman. Scientists used the electron beam to release the remainder of the nanoparticles from the joined bundle.

For the PVP-coated silver nanoparticles, scientists used glycerine as a dissolving agent. These particles were of size 6.53 (+-2.41). In the third preparation, scientists used serum albumin, the most common protein in blood plasma. The sulfur, oxygen, and nitrogen chemicals in BSA stabilized the nanoparticles, which were in the range of 3.12 (+-2.00) nm.

Scientists studied the absorption spectra of the different preparations to pinpoint their shapes. "Spherical nanoparticles absorbed in the blue region of the spectrum, for example," Yacaman said.

Also, the UV-Visible spectra graphs helped the group determine nanoparticle sizes. "The surface plasmon resonance peak wavelength increased with size," explained Yacaman.

Scientists tested, in vitro, each of three silver nanoparticle-preparations in HIV-1 cells. Yacaman and his colleagues incubated the samples at 37 C. After three hours and 24 hours, respectively, 0% of the cells were living.

The results showed that a silver nanoparticle concentration greater than 25 ug/mL worked more effectively at inhibiting HIV-1 cells. Plus, the foamy carbon was a slightly-better capping agent because of its free surface area. Size also played a role since none of the attached nanoparticles were greater than 10nm.

Scientists think the nanoparticles bonded through the gp120 glycoprotein knobs on HIV-1, using the sulfur residues on the knobs. The spacing between the knobs of ~22nm matched the center-to-center nanoparticle spacing.

Although this study shows silver nanoparticles may treat HIV-1, scientists need to research this relationship further. "We lack information regarding the long-term effects of metal nanoparticles," cautioned Yacaman. Scientists are forming a preventive cream for HIV-1, which they will test on humans.

Scientists are also studying other uses for silver nanoparticles. "We're testing against other viruses and the 'super bug (Methicillin resistant staphylococcus aureus).' Our preliminary results indicate that silver nanoparticles can effectively attack other micro-organisms," Yacaman said.


ज़ाकिर अली ‘रजनीश’ said...

उम्मीद बंधाती जानकारी।

RAM said...

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