Researchers have designed a programmable biomaterial that assembles itself into an infection-fighting structure once injected into the body. The findings, published in Nature Biotechnology this week, could lead to a non-surgical way to evoke natural defenses against cancers and viruses that have previously skirted immune detection.
Tumors are able to spread ravenously through the body because cancer evades attack from our immune system. Researchers have long hoped to build long-lasting resistance by compelling the immune system into attack mode—a technique known as immunotherapy.
Developed by Harvard’s David Mooney and colleagues, the new injectable, programmable material is comprised of tiny biodegradable, rod-like structures made from silica—called mesoporous silica rods (MSRs). After the rods are loaded with biological and chemical drug components, they can be delivered just under the skin using a needle.
Once in, the rods spontaneously self-assemble into a porous, 3D scaffold chock-full of nooks and crannies. These spaces are big enough to house dendritic cells. As the body’s surveillance system, dendritic cells trigger immune responses when they spy something harmful.
Pictured to the right is a microscope image of the scaffold, which is designed to recruit tens of millions of dendritic cells (pictured above). “We can create 3D structures using minimally invasive delivery to enrich and activate a host’s immune cells to target and attack harmful cells in vivo,” Mooney says in a news release.
After the 3D scaffold has recruited dendritic cells from the body, the drugs contained in the MSRs are released. This trips the dendritic cells’ surveillance trigger, and once they’re activated, the cells leave the scaffold and travel to the lymph nodes. There they sound the alarm and direct the immune system to attack cancerous cells. Back at the vaccination site, the MSRs dissolve away within a few months.
Additionally, the nanopores can be filled with antigens or any variety of drugs in numerous combinations. “By tuning the surface properties and pore size of the MSRs, and therefore controlling the introduction and release of various proteins and drugs, we can manipulate the immune system to treat multiple diseases,” study author Aileen Li of Harvard adds. The researchers hope that the technology can also be useful for fighting and preventing infectious diseases caused by killers like HIV and Ebola.
So far, the team has only tested the 3D vaccine in mice. The scaffold successfully attracted millions of dendritic cells before dispersing them to the lymph nodes to set off the immune response.
Images: Harvard School of Engineering and Applied Sciences