Imagine a day when doctors could inject you with cheap synthetic antibodies if your body wasn't producing enough of the virus- and bacteria-fighting proteins. While that scenario is a ways off, scientists from the University of California at Irvine may have taken the first step by successfully injecting "plastic antibodies" into the blood of mice to halt the spread of deadly bee venom.
The researchers created nanoparticle-size plastic polymers to encase melittin, a toxic peptide in bee venom that causes cells to rupture. Large quantities of melittin can lead to organ failure and death.
The researchers injected one group of mice with a lethal dose of melittin, and then injected them with the plastic antibodies.
The nanoparticles succeeded in "capturing" the antigens before they could disperse, thus greatly reducing deaths among the rodents, which also fared well in the weeks following the antibody injection, according to UCI chemistry professor Kenneth Shea, who worked on the project along with scientists from Stanford University and Japan's University of Shizuoka.
Mice in a separate control group were injected with the toxin but not the antibodies; they did not survive.
"Never before have synthetic antibodies been shown to effectively function in the bloodstream of living animals," Shea said. "This technique could be utilized to make plastic nanoparticles designed to fight more lethal toxins and pathogens."
The scientists, who detail their findings in a recent issue of the Journal of the American Chemical Society, designed the synthetic antibodies using a technique called "molecular imprinting," which linked melittin molecules with small molecules called monomers to create a network of long polymer chains. After the plastic hardened, the researchers removed the melittin, leaving nanoparticles with minuscule melittin-shaped holes.
When injected into the mice, the imprinted nanoparticles enveloped the matching melittin molecules before the toxin could wreak havoc on the creatures.
But the plastic antibodies could have applications beyond bees and mice. The idea is that unlike natural antibodies produced by live organisms and harvested for medical use, synthetic antibodies could be created in labs faster and more cheaply--and could boast a longer shelf life.
Melittin, while it can be life threatening, notably also carries potentially beneficial properties. Because the substance is known to kill cells, researchers at Washington University School of Medicine in St. Louis have harnessed it to destroy tumor cells.
Their research involved attaching melittin to nano-sized spheres they called "nanobees," which were injected into mice with cancerous tumors. The findings, published last year, indicated that the nanobees not only lessened the growth and size of cancerous tumors but also acted early to prevent cancer from developing.