Pack 'Em In -- Gold Nanoparticles Improve Gene Regulation

Feb 23, 2009

Investigators at Northwestern University have found that packing small interfering RNA (siRNA) molecules onto the surface of a gold nanoparticle can protect siRNAs from degradation and increase their ability to regulate genes involved in cancer. As a result of this discovery, cancer researchers have at their disposal a relatively straightforward method of delivering these potent gene-regulating agents into targeted cells.

Chad Mirkin, Ph.D., principal investigator of the Nanomaterials for Cancer Diagnostics and Therapeutics Northwestern University Center for Cancer Nanotechnology Excellence, led the research team that developed the methods needed to create these densely packed siRNA-nanoparticle conjugates. The investigators published their results in the Journal of the American Chemical Society.

One of the difficulties in working with potentially therapeutic siRNA molecules is that they are highly unstable, particularly in the presence of even trace levels of enzymes called nucleases that break down nucleic acids. To ensure that the surface of the gold nanoparticles was devoid of any nucleases, the investigators developed a harsh stripping method. To the researchers’ surprise, this treatment had no effect on the optical or physical properties of the nanoparticles. The researchers also found that without this pretreatment, they were unable to add any RNA molecules to nanoparticles. With the pretreatment, the resulting 13-nanometer gold nanoparticles held an average of 34 siRNA molecules each.

Using confocal microscopy, the investigators were able to watch the nanoparticles enter cultured tumor cells. More importantly, the researchers also showed that once inside the cell, the siRNA was able to escape from the nanoparticle surface and inactivate its gene target. The amount of gene silencing achieved with the siRNA-nanoparticle construct was double that observed when cells were treated with siRNA alone. The investigators note that other experiments suggest that this boost in therapeutic efficacy arises because of improved siRNA stability when associated with gold nanoparticles.

This work, which was detailed in the paper “Gene regulation with polyvalent siRNA-nanoparticle conjugates,” was supported in part by the NCI Alliance for Nanotechnology in Cancer, a comprehensive initiative designed to accelerate the application of nanotechnology to the prevention, diagnosis, and treatment of cancer. An abstract is available at the journal’s Web site.

Provided by National Cancer Institute

Explore further: Self-replicating nanostructures made from DNA

Related Stories

Exposing breast cancer using nanoscale polymers

May 13, 2015

Photoacoustic imaging is a ground-breaking technique for spotting tumors inside living cells with the help of light-absorbing compounds known as contrast agents. A*STAR researchers have now discovered a way ...

An improved method for coating gold nanorods

Mar 18, 2015

Researchers have fine-tuned a technique for coating gold nanorods with silica shells, allowing engineers to create large quantities of the nanorods and giving them more control over the thickness of the shell. ...

New nanodevice to improve cancer treatment monitoring

Oct 27, 2014

In less than a minute, a miniature device developed at the University of Montreal can measure a patient's blood for methotrexate, a commonly used but potentially toxic cancer drug. Just as accurate and ten ...

Recommended for you

Self-replicating nanostructures made from DNA

May 28, 2015

(Phys.org)—Is it possible to engineer self-replicating nanomaterials? It could be if we borrow nature's building blocks. DNA is a self-replicating molecule where its component parts, nucleotides, have specific ...

Non-aqueous solvent supports DNA nanotechnology

May 27, 2015

Scientists around the world are using the programmability of DNA to assemble complex nanometer-scale structures. Until now, however, production of these artificial structures has been limited to water-based ...

Nanosilver and the future of antibiotics

May 27, 2015

Precious metals like silver and gold have biomedical properties that have been used for centuries, but how do these materials effectively combat the likes of cancer and bacteria without contaminating the ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.