The first direct comparison of in vitro and in vivo screening techniques for identifying nanoparticles that may be used to transport therapeutic molecules into cells shows that testing in lab dishes isn’t much help in predicting which nanoparticles will successfully enter the cells of living animals.

The new study demonstrated the advantages of an in vivo DNA barcoding technique, which attaches small snippets of DNA to different lipid-based nanoparticles that are then injected into living animals; more than a hundred nanoparticles can be tested in a single animal. DNA sequencing techniques are then used to identify which nanoparticles enter the cells of specific organs, making the particles candidates for transporting gene therapies to treat such killers as heart disease, cancer and Parkinson’s disease.

The traditional technique for identifying promising nanoparticles examines how the particles enter living cells kept in lab dishes. To compare the new and old screening techniques, the researchers added barcoded nanoparticles to living cells in lab dishes, and injected identical barcoded nanoparticles into living animal models. They found almost no correlation between the nanoparticles identified as promising in the lab dish tests and those that actually performed well in the mice.

“DNA barcoding has the potential to advance the science of selecting nanoparticles for delivering gene therapies,” said James Dahlman, an assistant professor in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University and the study’s principal investigator. “Using this technique, companies and academic labs could pick out promising nanoparticles much more efficiently. That could accelerate the rate at which nanoparticle-based therapies move into the clinic, while reducing the amount of animal testing required.”

Image Credit:  Daryll A. Vanover, Kalina Paunovska, and Cory Sago at Georgia Tech

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