DNA Taxi: Photosensitive gold nanoparticles bind and release DNA

April 27, 2006

Despite few successes to date, gene therapy is a highly promising approach for medical therapy in the future. One of the biggest difficulties with this process is finding a suitable transport agent that can carry the nucleic acid being used as a “drug” into the diseased target cell. Killed viruses have been used as "taxis" for these genes, but these often have unexpected health consequences.

Recently, nanoparticles have been developed for gene therapy. A successful example of this has been described by V. M. Rotello, N. S. Forbes, and their co-workers in Massachusetts, USA.

They used tiny spheres of gold with tightly packed, positively charged hydrocarbon chains bound to their surface. These chains contain a photolabile bond that is stable to visible light but breaks when irradiated with UV light at a wavelength of 350 nm. This causes the positively charged fragment to fall off, leaving the gold sphere with a negative charge on its surface.

DNA contains negatively charged phosphate groups that allow it to bind to the positively charged gold spheres through electrostatic interactions. Cells that were brought into contact with gold spheres loaded with DNA allowed these “DNA taxis” to pass into their interior. The signal to “unload” was given by subsequent irradiation with UV light: it destroyed the photolabile bond, reversing the surface charge of the gold particles and releasing the DNA. Fortunately, the DNA was not only brought into the cytoplasm; it made its way to where it was needed: the cell nucleus. This is the location in the cell where DNA molecules are copied for translation into proteins or are multiplied for cell division.

This process offers a relatively simple possibility for the transport and controlled release of DNA into living cells. In addition, the authors believe that this method should make it possible to steer interactions with other biomolecules, such as proteins or pharmaceutical agents, making it possible to target specific cells.

Citation: Vincent M. Rotello et. al., Angewandte Chemie International Edition 2006, 45, No. 19, 3165–3169, doi: 10.1002/anie.200600214

Source: Angewandte Chemie

Explore further: Computers made of genetic material? Researchers conduct electricity using DNA-based nanowires

Related Stories

Rapid, Low-Cost DNA Testing

January 8, 2007

Professor Lewis Rothberg of the University of Rochester Chemistry Department received a NYSTAR grant in August 2006 to continue working on a recent discovery by Huixiang Li, a research associate in his group: how to rapidly ...

Recommended for you

Particles self-assemble into Archimedean tilings

December 8, 2016

(Phys.org)—For the first time, researchers have simulated particles that can spontaneously self-assemble into networks that form geometrical arrangements called Archimedean tilings. The key to realizing these structures ...

Nano-calligraphy on graphene

December 8, 2016

Scientists at The University of Manchester and Karlsruhe Institute of Technology have demonstrated a method to chemically modify small regions of graphene with high precision, leading to extreme miniaturisation of chemical ...

ANU invention to inspire new night-vision specs

December 7, 2016

Scientists at The Australian National University (ANU) have designed a nano crystal around 500 times smaller than a human hair that turns darkness into visible light and can be used to create light-weight night-vision glasses.

0 comments

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.