To use an overworked phrase, it’s a paradigm shift: Cancer research is learning how to ‘think small’ with the potential of nanotechnology – nanoparticles specifically. It’s a shift because medical science has been accustomed to cancer-fighting techniques on the level of bringing cannons to kill a fly. Where doctors once treated cancer with a body-wide dose of chemotherapy, or maybe a targeted dose that still made a mess of the liver; nanotechnology makes it possible to think of killing individual cancer cells, or about sending in a squad of chemo-laden nanoparticles that can deliver a punch to specific kinds of cancer cells in places no other chemistry (or radiation, or scalpel) can reach. For example, here are two recently announced advancements in nanomedicine…

The first announcement sort of fits the battle metaphor. It’s characterized as ‘zapping nanobubbles.’ …Researchers at Rice University (Houston, USA) have developed a technique for treating cancer cells – one at a time if appropriate – by using gold nanoparticles. The nanoparticles are targeted for a specific type of cancer, where they attach to individual cells. Then a laser device, set to a specific frequency, causes the gold nanoparticles to heat causing either a (nano)bubble inside the cancer cell or exploding it (zapping).

“Single-cell targeting is one of the most touted advantages of nanomedicine, and our approach delivers on that promise with a localized effect inside an individual cell,” said Rice physicist Dmitri Lapotko, the lead researcher on the project. “The idea is to spot and treat unhealthy cells early, before a disease progresses to the point of making people extremely ill.”

[Source: EurekAlert]

The technique is not only good for an onco-shooting gallery. It can also be used for diagnosis because the nanobubbles are highly visible to microscopes. The researchers refer to this as a ‘theranostic’ opportunity – combining diagnostics followed immediately by therapy. The technique has been tested on human cancer cells. The next steps are trials of various methods of application.

The second announcement is less dramatic. It involves using nanoparticles to cross mucus barriers. That’s less dramatic, but it’s an important achievement. The human body has many organs with natural mucus barriers – the stomach, intestines, lungs, eyes, throat, cervix – some of which are nearly impermeable to traditional drug chemistry. The nanoparticles developed by the Johns Hopkins School of Medicine (Maryland, USA) have a special outer layer of polyethylene glycol (commercially, Carbowax), which makes it possible for the particles to penetrate mucus membranes with ease. The nanoparticles have been created with an inner layer of polysebacic acid, which can hold a variety of drug or genetic molecules, making the particles a drug delivery system that can be targeted for specific diseases. Better yet, the nanoparticles are designed to release their drug cargo as they biodegrade. In effect, the dissolving of the particles is the timer for release of the drugs, and when that’s over, the nanoparticle compounds are flushed out with normal bodily systems.

The original target for these nanoparticles is cystic fibrosis, which is notorious for creating unusually thick and sticky mucus in the lungs and gut.

The team’s work was reported recently in the Proceedings of the National Academy of Sciences. Hanes’ collaborators included cystic fibrosis expert Pamela Zeitlin, a professor of pediatrics at the Johns Hopkins School of Medicine and director of pediatric pulmonary medicine at the Johns Hopkins Children’s Center.

“Cystic fibrosis mucus is notoriously thick and sticky and represents a huge barrier to aerosolized drug delivery,” she said. “In our study, the nanoparticles were engineered to travel through cystic fibrosis mucus at a much greater velocity than ever before, thereby improving drug delivery. This work is critically important to moving forward with the next generation of small molecule and gene-based therapies.”

[Source: Nanotechnology Today]

This use of nanoparticles has many potential applications, some of which are in development.