Tag: nanoparticles

Detecting single cancer cells with light: A podcast

Photo by Burak Kebapci

When cancer is spotted early, it’s much easier to thwart. So researchers, including Stanford’s Jennifer Dionne, PhD, are working to detect cancer more effectively. Dionne, an associate professor of materials science and engineering, is developing a nanomaterial-based probe that may be able to detect a single cancer cell.

She described her work in a recent episode of the Future of Everything radio show, hosted by Russ Altman, MD, PhD, a Stanford professor of bioengineering, of genetics, of medicine and of biomedical data science.

“What our lab is trying to do is create light-emitting nanoparticles that change their color when there is an applied force on the nanoparticles. So that way we can make mechanical forces visually perceptible,” she explained to Altman. These nanoparticle already change color in response to the tiny forces generated by cells and groups of cells, she said, and cancer cells are known to exert more force on their environment than healthy cells.

Dionne explained: “Generally a cancer cell wants to take up a lot of nutrients and it’s basically growing and dividing more quickly than a healthy cell. You can imagine given the speed of replication that it’s going to exert a higher force on its environment than a healthy cell. So our nanoparticles offer the ability to detect even a single cancer cell based on the forces that that cancer cell is exerting on its environment.”

That could help pathologists spot abnormal cells in a biopsy sample, she said. “This could be a really cool in vitro probe of whether or not in a biopsy [sample] you have even one cancer cell, which you can tell just by looking at the color the nanoparticles are emitting,” she told Altman.

Although their primary focus was on the development of nanomaterials with energy and biomedical applications, the conversation did take a few interesting twists. I particularly enjoyed their discussion on the design challenges behind making a Harry Potter invisibility cloak. Hint: Like water waves flowing around a rock, you need to create a cloak that allows light waves to flow smoothly around the hidden object so they emerge on the other side as if they hadn’t passed through the object — it’s difficult, but they’re working on it.

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.

Trojan Horses: Nanoparticles sneak drugs into brain to battle cancer

Photo by dierk schaefer
Photo by dierk schaefer

I just read an interesting article in the Berkeley Science Review about using nanoparticles to make chemotherapy more effective against a type of brain cancer called glioblastoma. I was then surprised and proud when I realized one my former science-writing students, Dharsi Devendran, wrote it.

Although rare, glioblastoma is an invasive and deadly brain cancer with octopus-like tentacles that are difficult to completely remove with surgery. Even the standard combined treatment of surgery, radiation and chemotherapy isn’t very effective — people typically die within months of diagnosis. So researchers are actively searching for better treatments.

Devendran explains:

Although it is difficult to fight, glioblastoma also has a weakness. In its rush to feed itself, it accelerates the blood vessel formation process and creates hole-riddled blood vessels around the tumor. Because cancer drugs are small enough to slip through these holes, they can exploit this defect—but they also need a strategy to cross the blood-brain barrier in order to reach the tumor.

Acting like a security system for the brain, the blood-brain barrier is a network of blood vessels that allow essential nutrients to enter while blocking harmful molecules. Unfortunately, it also blocks life-saving chemotherapy drugs, unless researchers can find clever ways to sneak them through the barrier.

Ting Xu, PhD, professor of materials science at UC Berkeley, and her collaborators are developing tiny nanocarriers that can envelop and protect chemotherapy drugs as they move through the blood, across the blood-brain barrier, and into the brain to the glioblastoma tumor tissue.

The researchers designed a new nanocarrier, called a 3-helix micelle (3HM), out of proteins with molecules on the surface that fit into specific proteins found only on the surface of the tumor cells — like fitting a key into a lock. Once the 3HM nanocarriers access the tumor cells, they release their chemotherapy drugs to help destroy the glioblastoma.

Xu’s team has shown that their 3HM nanocarrier is twice as effective at reaching glioblastoma cells as liposomes, a nanocarrier made of fatty acids that is a standard in nanotechnology drug delivery. This is in part because the 3HM is five times smaller than liposomes.

“We still don’t understand the mechanism completely,” said JooChuan Ang, a graduate student in Xu’s group, in the article. “Size is definitely a factor, but there could be other factors that contribute…”

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.

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