Traditional antibiotics like doxycyclin and vancomycin—the kind that many bacteria can now resist because of their overuse—work by getting inside the bacterial cell and interfering with essential cellular processes. Charged peptides have been proposed as alternatives, since they work by electrostatically interacting with the negatively charged bacterial cell wall, poking holes in the bacterial cell membrane and thereby killing the bacteria.
Nederberg et al. made charged polymers out of cyclic carbonates, which are nontoxic and biodegradable. Their degradation produces alcohol and carbon dioxide, and they degrade slowly, so they have prolonged antimicrobial functions inside the body and long shelf-lives outside of it. Because of their amphiphilic nature—they have a positively charged region, which is hydrophilic, but also a hydrophobic region—these nanoparticles spontaneously form small spheres in water, so they can hide their hydrophobic parts inside.
The nanostructures were effective against Gram-positive bacteria, methicillin-resistant Staphylococcus aureus (MRSA), and the fungus Cryptococcus neoformans, and had an efficiency comparable to that of conventional antimicrobials at their best, all while leaving red blood cells alone.
When injected into mice, the antimicrobial nanoparticles did not exhibit any significant toxicity over the test period, which lasted for fourteen days. It's not yet exactly the nanotechnological immunomodulation described by Neal Stephenson in The Diamond Age… but it's getting close.
VIA Arstechnica
SOURCE Nature
