by Robin Andrews
Each month, fresh research appears to reveal a new way of delivering chemotherapy drugs to tumors; just this week, scientists announced that they could use a sort of “ultrasonic screwdriver” to non-invasively open up the blood-brain barrier in order to get drugs inside the brain. Now, a new study in Nature Communications reveals how scientists have genetically engineered algae, transforming them into targeted drug delivery systems.
The application of nanoparticles in this field has seen an uptick over the last decade. Often made of graphene – a genuinely multipurpose wonder material – these biodegradable-yet-tough carbon particles can be designed to imprison anti-cancer drugs inside them, transporting them through the bloodstream towards their target tumor. Some are even able to heat up when triggered, causing them to disintegrate their target cancer cells.
This new study takes the nanoparticle delivery method and modifies it slightly. Instead of using carbon-based nanoparticles, the researchers switched to silicon. In this instance, they used diatoms, a common type of photosynthesizing algae. These tiny organisms have silica-based skeletons that, although resistant to erosion, are ultimately biodegradable.
Specifically, the common diatom Thalassiosira pseudonana was altered to have an enhanced shell, one that effectively binds to a certain type of antibody, giving the researchers an attachment point for cancer cell-targeting antibodies. Neuroblastoma – a rare cancer commonly found in the adrenal gland of children – and B-cell lymphomatumors were the chosen targets of this research; as such, the genetically modified algae shells were coated in antibodies that would specifically target these cells.
Image credit: A schematic showing the antibodies binding to the surface of the biosilica (green) containing drug particles (yellow), "attacking" the cancer cell (purple). Mr. Marc Cirera.
Loaded with chemotherapy drugs, the “biosilica” was tested both in vitro in the lab and on live mice. In both cases, it was shown to be incredibly effective: small doses killed up to 90% of the cancerous cells in a petri dish, and one dose given to mice significantly shrunk their tumors. As the study states, these biosilica drug-containing algae appear to be effective, “versatile backpacks” for the targeted delivery of anti-cancer medication.
Although this isn’t the first time that silica nanoparticles have been used in this regard, previous experiments have involved a costly production process that also involved the use of toxic chemicals, such as the highly potent hydrofluoric acid. Conversely, algae can be grown quickly and cheaply using just water and light, and they’re perfectly biodegradable, breaking down when they’ve performed their chemotherapy drug delivery. Importantly, this targeted method leaves healthy cells intact – something traditional chemotherapy fails to do.
“Although it is still early days, this novel drug delivery system based on a biotechnologically tailored, renewable material holds a lot of potential for the therapy of solid tumors, including currently untreatable brain tumors,” Professor Nico Voelcker, a nanomedicine expert at the University of South Australia and lead author of the paper, said in a statement.
