Most cancers “vascularize,” meaning the cancer cells release chemicals into surrounding tissues, causing new blood vessels to grow toward them. The new blood vessels usually grow right out of a nearby artery or capillary, like orchid roots. Unlike orchid roots, cancer vascularization is bad. More blood means more nutrients, and more nutrients help cancers grow faster. And the nearer a cancer is to blood flow, the more likely it is the cancer can spread to other parts of the body.
There is good news, though. Vascularizing cells have unique properties at their surfaces. Most cells that misbehave — including cancer cells and the cells they recruit — overexpress some protein that ends up in the membrane, whether it’s a transporter, a receptor, or some sort of cell-surface recognition factor. As mentioned in a previous post, these overexpressed proteins dotting the cells could be used as handles…
One area of investigation in nanomedicine (nanotech + medicine) is looking at how synthetic, silicon-based particles might be built to bind to these cells, using the overexpressed surface proteins as a means to stick in place. These sticky nanoparticles would be loaded with chemotherapy drugs.
But what shape should the nanoparticles be? What size? And what surface chemicals, added to the silicon particles like a sugary frosting, will make them stick best to their targets? Scientists at my hospital call this the “3 S problem.”
A couple of papers our scientists published recently suggest the best shape is a disc. At least when it comes to vascularizing cancers.
A sphere-shaped nanoparticle presents too much area to a fast-moving bloodstream, and that makes them more likely to get pushed off their cancer targets. Rod-shaped nanoparticles aren’t sticky enough. But disc-shaped nanoparticles (the medium-hot nanoporridge) work well. Disc-shaped nanoparticles present maximum surface area to the sides of target cells, making the nanoparticles stick better, while also maintaining a minimal profile to the never-ending rush of blood.