Life Science Technologies: Prognosis for Nanotechnology Treatments
Science Magazine - July 6, 2012
Around the world, biomedical researchers are exploring the possible ways that nanotechnology could enhance human health. At the University of Melbourne in Australia, for example, Frank Caruso, professor of chemical and biomolecular engineering, explores a variety of self-assembly strategies to create particles for potential use as therapeutics. "We develop systems with defined physical and chemical properties to nanoengineer these systems to enhance payload delivery and achieve site specificity," says Caruso. For drug delivery, the particles can be in the range of roughly 20 nm to 1 μm. "The size depends on the application," Caruso says, "but targeting specific delivery sites usually requires a small particle to get it there." He adds, though, that the actual size constraints also depend on a particle's shape, plus mechanical properties like elasticity and even the particle's surface chemistry.
The ideal drug delivery system should possess several features. Of course, it needs to get the drug to the intended target, but there's more. The particle must also be biocompatible and biodegradable, so that the cellular machinery can break down the particle to release the therapeutic. Then, the remaining particle components need to be nontoxic. It seems like a lot to ask, but Caruso says, "There's an enormous range of polymers that can be used for assembling particles."
For example, Caruso and his team developed a polymer-based carrier with a roughly 10 nm-thick wall that could transport drugs. "It provides highly elastic mechanical properties that can be tuned," Caruso says. "We're working on understanding how size, shape, and elasticity influence biological interactions, and this helps us nanoengineer the control of drug release and the particle's circulation lifetime." He makes sure to add that such work depends on a multidisciplinary team, including biologists, chemists, immunologists, materials scientists, medical researchers, and more.
Some medical applications could benefit from a nanoscale view, like the one provided by field emission scanning electron microscopy (FESEM). Compared with conventional SEM, says Craig Schwandt, senior research scientist at McCrone Associatesin Westmont, Illinois, "The biggest difference is the diameter of the beam, which is 100 to 1,000 times narrower in FESEM." As a result, FESEM can distinguish structures that lie closer together than SEM can. "The best resolution for SEM is usually about 500 nm apart," says Schwandt, "but FESEM can resolve artifacts that are only 1 nm apart."