Bioengineering researchers at Rice University have developed ultrasmall, stable gas-filled protein nanostructures that could revolutionize ultrasound imaging and drug delivery. Unlike current microbubbles or nanobubbles that are too large to cross biological barriers effectively, the novel diamond-shaped 50-nanometer gas vesicles (50-NM GVs) — approximately the size of viruses — are believed to be the smallest stable, free-floating structures for medical imaging ever created. Source: Rice University News