Tiny particles of silica can act as DNA carriers, providing a non-viral method of gene therapy, new research shows.

The idea of gene therapy is simple enough - replace defective or absent genes in cells with properly functioning genes. In practice, it’s tricky to get the new genes into the cells. Most methods use a modified virus to ‘infect’ the cell with its genetic payload, but this has drawbacks.

Dr. Paras N. Prasad and colleagues, from the State University of New York at Buffalo, synthesized modified silica nanoparticles, about 1/10 of a millionth of an inch in diameter, that were able to attach to sequences of DNA.

When the nanoparticles were incubated with test cells in a lab dish, they were readily absorbed into the cells, the researchers report in the Proceedings of the National Academy of Sciences admitted to the cytoplasm.

Once in the cell, the nanoparticles protected the attached DNA from being degraded by enzymes, and delivered the DNA to the cell’s nucleus. There, the gene was successfully incorporated into the cells own DNA, the team found.

Some of the nanoparticles were labeled with fluorescent dyes so that they could be tracked in the cell under a microscope.

The use of modified nanoparticles combined with optical tracking “provides a promising future direction for targeted therapy with enhanced efficacy,” the investigators state.

SOURCE: Proceedings of the National Academy of Sciences, online December 27, 2004.