Using gold nanoparticles combined with DNA, scientists at Northwestern University now have demonstrated a new method for developing antisense drugs that outperform conventional antisense agents. The findings will be published May 19 in the journal Science.
A major challenge has been delivering antisense drugs to cells inside the body while avoiding their break down along the way. The Northwestern team shows that by attaching multiple strands of antisense DNA to the surface of a gold nanoparticle (forming an "antisense nanoparticle") the DNA becomes more stable and can bind to the target messenger RNA (mRNA) more effectively than DNA that is not attached to a nanoparticle surface (as in commercial agents).
When compared to antisense DNA complexed with commercial agents such as Lipofectamine and Cytofectin, the antisense nanoparticles were more effective in gene knockdown (decreasing gene expression and protein production), were less susceptible to degradation resulting in longer lifetimes, exhibited lower toxicity and were more readily absorbed by cells, exhibiting a greater than 99 percent uptake.
"When mutations in the body's genetic material cause too many copies of certain proteins, cancer and other diseases can result," said Chad A. Mirkin, director of Northwestern's Center for Cancer Nanotechnology Excellence, who led the study. "Whereas typical drugs target the proteins, it is possible through gene therapy to target the genetic material itself before it is ever made into copies of harmful proteins. One way to target the genetic material is to block the messenger RNA by using 'antisense DNA,' which prevents the message from ever becoming a protein."
Once inside cells, the