Nanoparticle Drug-Release in Response to pH Level in Cells

[grantnano]

Researchers at Georgia Institute of Technology Use Polymeric Nanoparticles to Release a Drug in Response to a Cancer Cell’s pH Environment

One of the characteristics that distinguish a cancer cell from a normal cell is the former’s acidic interior. Researchers have had some success capitalizing on this difference by creating nanoparticles that are stable in the more basic environment of the blood stream and the extracellular environment but that unfold when they enter the acidic, or low pH, environment inside a cancer cell, releasing their drug payload then. Now, a research team from the Georgia Institute of Technology has created a new polymeric nanoparticle that not only releases its payload under acidic conditions, but also disintegrates into small, non-toxic molecules that should be easily degraded by the body.

Reporting their work in the journal Bioconjugate Chemistry, Niren Murthy, Ph.D., and his graduate student Michael Heffernan describe the methods they developed to create a new polymer that they call PPADK. This polymer contains an unusual chemical linkage that causes it to fall apart when the pH drops below 5. The pH of blood and the interior of healthy cells, in contrast, is about 7.4.

When mixed vigorously with water, the polymer forms stable nanoparticles. If drug molecules are included in the mixture, the drug becomes entrapped within the nanoparticle structures.

This work is detailed in a paper titled, “Polyketal nanoparticles: a new pH-sensitive biodegradable drug delivery vehicle.” An abstract is available through PubMed.

Source: NCI Alliance for Nanotechnology in Cancer.

URL: http://nano.cancer.gov/news_center/nanotech_news_2005-12-19c.asp

This story was posted on 20 December 2005.