Oct 8 2014
Image Credit: RAJ CREATIONZS
The human immunodeficiency virus (HIV) is a lentivirus causing the deadly disease acquired immunodeficiency syndrome (AIDS) that destroys the human immune system causing life-threatening infections.
Presently, nanotechnology is being employed by scientists in the detection of HIV. Nanocarriers are capable of facilitating delivery across the blood-brain barrier and effective internalization in cells by receptor mediated or non-specific endocytosis. Failed HIV drugs can even be made to work using gold and other metal nanoparticles.
Nanoparticles Carrying Bee Venom
Researchers at the Washington University School of Medicine in St Louis have shown that nanoparticles loaded with a bee venom toxin can destroy the human immunodeficiency virus (HIV) while leaving the neighboring cells unharmed.
This discovery is a key step in the development of a vaginal gel that may prevent HIV from spreading. According to a research instructor in medicine, Joshua L Hood, in places where HIV is spreading at very rapid rates, this gel can be used as a preventive measure to hinder initial infection.
Bee venom contains a toxin known as melittin that is capable of forming holes in the protective envelope surrounding HIV and other viruses. The senior author of the paper and the J. Russell Hornsby Professor of Biomedical Sciences, Samuel A. Wickline, MD, also showed that nanoparticles loaded with melittin can destroy tumor cells. Protective bumpers were added to the surface of the nanoparticles so that normal cells are not harmed.
When the nanoparticles contact normal cells that are much larger in size, they simply bounce off. HIV is smaller than the nanoparticle, hence gets attached between the bumpers and comes in contact with the nanoparticle surface.
A benefit of this technique is that the nanoparticle attacks a major part of the structure of the virus. On the other hand, most drugs presently available prevent replication of the virus but do not stop the initial infection.
Researchers also anticipate that the nanoparticles can be used for existing HIV infections especially drug-resistant ones. The nanoparticles can be intravenously injected and can clear HIV from the blood stream.
They believe that many viruses including hepatitis B and C depend on the same kind of protective envelope and will be vulnerable to nanoparticles loaded with melittin. It is also believed that this nanoparticle will be as safe for sperms as they are for vaginal cells.
Gold and Silver Nanoparticles
Nanotechnology and nanomaterial properties offer several ways to inhibit viral mechanisms. Gold and silver nanoparticles have been researched extensively for use in bioassays, imaging and therapy and are being considered for HIV therapy now.
In a research conducted in 2009, gold nanoparticles were attached to SDC-1721, a fragment of the HIV inhibitor TAK -799 that acts via allosteric inhibition of the CCR5 receptor. SDC-1721 gold nanoparticles showed activity that was comparable to TAK-779.
According to this, presenting tiny molecules on the gold nanoparticle surface can convert inactive drugs into viral inhibitors. Silver nanoparticles are capable of interacting with HIV and stopping in-vitro infection.
The interaction of the silver nanoparticles with HIV was done in a size-dependent manner since particles in the range of 1 to 10 nm alone interacted with the virus. This is an attractive drug-free approach of viral inhibition and more work is required for investigating interactions between the virus and metal nanoparticles.
University of Liverpool scientists are heading a £1.65 million project for the production and testing of the first nanomedicine for the treatment of HIV/AIDS. The Engineering and Physical Sciences Research Council (EPSRC) has funded this project, which commenced in 2012.
The project aims at producing less expensive and more effective medicines with minimal side effects and can be easily administered to children and newborns. New therapy alternatives were obtained by the modification of existing HIV treatments known as anti-retrovirals (ARV).
ARV drug particles have been recently produced at the university at the nanoscale, considerably bringing down the variability and toxicity in the way different patients respond to therapies.
Professor Steve Ranard from the Department of Chemistry of the university stated that nanoparticles are being daily used to treat several conditions globally. He stated that if it were possible to show substantial potential from their planned clinical work then IOTA NanoSolutions will advance the research further. He also added that novel formulations will be tested for children in developing nations, offering HIV patients globally the prospect of more effective and safer treatments.
Professor Andrew Owen from the Department of Molecular and Clinical Pharmacology of the University added that the data obtained thus far is quite attractive and will enable reduction of dosage to control the HIV virus. Presently, the number of HIV drugs available for kids is very limited and include many risks such as over- and under-dosing.
Nanomedicines disperse in water, hence can be easily given even to newborns. ARV nanomedicines will be manufactured as part of the project using commercially relevant methods under clinical-grade manufacturing conditions.
Researchers have observed that combination antiretroviral therapy (cART) limits HIV replication significantly. However, lifelong and daily treatment is needed to manage the illness of the patient since cART does not remove the infected cells neither does it reconstitute HIV-specific immunity that can destroy infected cells.
Several nanomedicine classes have been developed with the following characteristics to combat HIV:
- Eradicating the virus by activating latently infected CD4+ T cells and flushing reservoirs
- Preventing infection using microbicides with drug half-life and enhanced epithelial penetration
Nanomedicines can considerably improve the health of HIV infected people and they are economically feasible too. Hopefully this promising technology will help find a cure for HIV/AIDS in the forseeable future.
References and Further Reading