Northwestern scientists cast collapsible nanonet to trap and deliver drugs

The Northwestern team sought to replicate the ability of naturally occurring molecules like DNA and peptides to swiftly self-assemble and form diverse structures using human-made polymer systems. (Kameleon007/GettyImages).

Previous attempts at self-assembling drug delivery systems have come up short partly because of timing challenges, complexity and scalability. Now, Northwestern University scientists think they may have a solution.

The researchers identified a polymer that could be used to form a net to quickly trap and deliver a slate of drugs. The "nanonet" could prove more efficient than other nanoparticle drug delivery systems, help rapidly generate vaccine formulations, and even purify water, the scientists posit in a press release.

Under lead study author Evan Scott, Ph.D., a profressor at Northwestern’s McCormick School of Engineering, the team set out to use synthetic polymers to replicate the ability of naturally occurring molecules such as DNA and peptides to swiftly self-assemble and form diverse structures.

Scott’s team settled on polypropylene sulfone (PPSU) homopolymer, which forms a “wide net” in a dimethylsulfoxide (DMSO) solution. Adding more water to the solution causes the net to collapse, snatching up drugs loaded into the solution and trapping them in self-assembling nanogel delivery vehicles, Scott explained.

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The platform captured more than 95% of proteins, DNA or small-molecule drugs—both alone and in combination—in a study published in the journal Nature Communications. That’s quite an upgrade from the 5% to 20% loading efficiency typically seen in other nanoparticle drug delivery systems, Northwestern pointed out in its release.

Previous attempts at self-assembling drug delivery systems have hit snags over time, costs, labor and scalability, Scott said. Many of those systems are limited in their ability to load large or multiple therapeutics—especially proteins. Meanwhile, Northwestern’s nanonet “can stably load nearly any therapeutic molecule with high efficiency,” he added.

The system isn’t all that different from a fishing net, with therapeutics the catch in this case, Fanfan Du, Ph.D., a postdoctoral fellow in Scott’s lab, said. The net “first spreads out due to electrostatic repulsion and then shrinks upon hydration to trap ‘fish,’” he said.

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The team figures its nanonet could be used to deliver a wide variety of drugs. The system could also help generate vaccine formulations, which typically depend upon the simultaneous capture and delivery of a variety of molecule types, they said. It may have diagnostic applications, too.

Plus, the team thinks it could cast its nanonet beyond the healthcare field to help purify water. Just as the net collapses to trap drugs, it could also ensnare contaminants, leaving pure water behind, the team thinks.