Filling tumors with oxygen makes them more susceptible to treatment. In seeking a path to deliver more oxygen to tumors, researchers turned to an unlikely source of inspiration: foam used in cooking, like the whipped cream that baristas use to top hot chocolates. Utilizing the same whipping siphon used in the culinary world, they created a food-based foam that can be injected directly into tumors and showed that it was effective in reducing treatment resistance in mouse tumors.
In the body, tumors keep themselves in a hypoxic, or oxygen-deprived state. This makes them notoriously resistant to common treatments including chemotherapy and radiation. In an effort to take away this defense, researchers have used oxygen-increasing techniques such as hyperbaric oxygen therapy and a type of oxygen delivery known as microbubble infusion. “However, the challenge has been how to deliver an effective dose of oxygen in a safe, controlled fashion,” said James Byrne, an associate professor of biomedical engineer from the University of Iowa.
So Byrne and fellow researchers from UI – as well as from Harvard Medical School, MIT, and the Beth Israel Deaconess Medical Center – set out to find a way to directly inject tumors with oxygen. Turning to the world of molecular gastronomy, which involves transforming various edible substances to foam, they reverse-engineered a whipping siphon to use oxygen instead of the more standard nitrous oxide. The resulting foams were named gas-entrapping materials, or GeMs.
“These GeMs are very simple, with just three ingredients: the gas, the foaming agents, and the thickening agent,” said Byrne. “We use several unique, custom-built pressurized systems to incorporate high concentrations of gas into small volumes of these biocompatible materials, which can be injected or implanted into tissues and allow for prolonged, controlled release of the gas.”
In one iteration of the foam, the researchers used a polymer consisting of natural carbohydrates similar to the candy, Pop Rocks.
Next, the researchers carried out experiments on mice bearing either prostate cancer or a type of sarcoma known as malignant peripheral nerve sheath tumor (MPNST). MPNSTs are extremely difficult to operate on because doing so can easily damage the nerves around which they wrap, so finding a way to make them more susceptible to current best-of-care treatments could go a long way toward improving patient outcomes. In both types of tumors, the new oxygen-delivery foams increased tumor responsiveness to chemotherapy and radiation treatments.
Because the foams are made out of edible materials and oxygen, the researchers feel that if human trials are successful, rolling out the treatment as another tool in the cancer-fighting toolbox (which, interestingly, also contains ideas on how to fight cancer by starving it of oxygen) is highly likely.
“One of the aspects of this project that really excited me was the combination of cancer biology principles with material science to create something that can be really impactful,” said study first author Jianling Bi, a research scientist in Byrne’s lab.
A paper on the study has been published in the journal, Advanced Science.
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