Researchers discover that biomimetic nanosystem can deliver therapeutic proteins to selectively target cancerous tumors, according to a study published on June 15, 2018.
This study was conducted by the researchers at Penn State. A protein toxin known as gelonin was used to cage the proteins in self-assembled metal-organic framework (MOF) nanoparticles to protect it from immune system of the body. The MOF was further masked in a coating that was made from cells from tumor. This was done to enhance the longevity of the drug in the bloodstream and to selectively target the tumor.
The alien molecules in our body are either attacked or flushed out of the body through the spleen or liver by the body’s immune system. However, small particles called extracellular vesicles that communicate with other cells in the body and send a ‘don’t eat me’ signal to the immune system are released by cells. Siyang Zheng, associate professor of biomedical and electrical engineering at Penn State, said, “We remove 99 percent of the contents of these extracellular vesicles and then use the membrane to wrap our metal-organic framework nanoparticles.”
A one-pot approach in aqueous environment was used to achieve self-assembly of MOF nanoparticles and encapsulation of proteins. The extracellular vesicle membrane gets buckled on the metal affinity sites on MOF surfaces. The nanoparticle system continues to circulate in the bloodstream till the tumor is identified and locked on to the cell membrane. By a process called as endocytosis, nanoparticles are ingested by the cancer cells.
When the nanoparticles are inside the cell, the metal-organic framework nanoparticles break apart due to the higher acidity of the cancer cell’s intracellular transport vesicles and the toxic protein is released into cytosol, which kills the cell. According to the researchers, the nanosystem will be an efficient tool for the targeted delivery of other proteins that require cloaking from the immune system.