Nanoparticles: Designing Medicine at the Molecular Level

The greatest problem with traditional cancer treatments is lack of specificity. Treatments such as radiation therapy and chemotherapy kill healthy cells along with tumor cells, causing negative side effects in patients (1).

Scientists believe that nanotechnology-based treatments can solve the issue of specificity. Nanoparticles used to treat cancer are approximately 100 nanometers – or 100 billionths of a meter – in size. While they are too large to fit through the blood vessels of healthy tissue, they can easily penetrate cancerous blood vessels, as tumors have more permeable vessels due to their rapid growth (1). The exteriors of these nanoparticles can also be decorated with molecules that specifically bind to cancer cells. Collectively, nanoparticle treatments are less harmful to patients than traditional treatments (2).

On January 26, 2014, scientists Leo Chou, Kyryl Zagorovsky, and Warren Chan published their research on constructing superstructures of nanoparticles using DNA to improve the functionality of nanoparticle treatments (3). The scientists created a “core-satellite” architecture of nanoparticles: one nanoparticle core surrounded by different layers of satellite nanoparticles. Each nanoparticle was grafted with strands of DNA and linker strands with complimentary sequences to bind the nanoparticles together. After the superstructures were built, the polymer polyethylene glycol or PEG was added to improve biological stability (3).

By systematically altering aspects of these nanoparticle superstructures such as the nanoparticle size, length and number of linker DNA strands, length and number of PEG strands and the number of satellite layers, the scientists could identify the properties of these superstructures. They found that modifications of these superstructures constituted ideal delivery mechanisms for cancer drugs.

During treatment, tumor cells – but not immune cells – absorb the nanoparticle superstructures. Because immune cells do not incorporate the nanoparticles, the superstructures have low toxicity. Moreover, once inside tumor cells, the superstructures degrade into their nanoparticle components, allowing the particles to spread within the tumor cells (3). This also allows drugs present in the superstructure to remain biologically active.

This research, while only in its preliminary stages, is promising. It provides a glimpse of cancer treatment that leaves healthy tissue alone—a progress greatly desired in current cancer treatments.

References:

1. Available at: http://www.pbs.org/wgbh/nova/next/body/nanoparticles-in-cancer-treatment/

2. Available at: http://www.nature.com/nrd/journal/v7/n9/execsumm/nrd2614.html

3. Available at: http://www.nature.com/nnano/journal/v9/n2/full/nnano.2013.309.html